CHAPTER 2 : Strateqies To Improve The Qualitv Of Black

Pepper Cultivated In Kerala

2.1 Introduction

Black pepper (Piper nigrurn Linn.), the king of spices is the world's most important

spice. This spice is the prime dollar-earning crop to lndia fetching an annual export of

Rs.41651- million to the country (Rajan and Sarma, 2000), which is about 70% of the total

earnings from spices to the national economy. Black pepper is cultivated in approximately

2,00,000 ha in lndia with annual production of about 50,000 MT. This accounts for more

than 50% of world's area of pepper cultivation, but contributes only around 25% of global

production. Though lndia had a pre-eminent position during the 1950's by meeting 80% of

world's supply of black pepper, the export has now dwindled to less than 33% as a result

of stiff competition from newly emerged pepper producing countries such as Indonesia,

Malaysia, Brazil and Vietnam (Senthikumara and Vadivel, 2000; Thomas eta/., 2002).

Black pepper is obtained from the plant Piper nigium Linn. White pepper and

green pepper are also developed as high commercial value products (Sudarshan, 2000)

in addition to a number of different value added products (Appendix IV).

Black pepper contains an array of phytochemicals. Volatile oil, oleoresin and

piperine are the important products of high commercial value extracted from pepper.

Accountability for the bioactive property of these extracts is due to the action of these

chemical principles. List of various chemical compounds present in black pepper is given

in Appendix V.

Piper nigrurn Linn. is believed to have originated in the evergreen forests of

Western Ghats of Peninsular lndia (Kandiannan, 2000). Out of more than 70 different

cultivars that are cultivated in Kerala Panniyur I is considered to be the most outstanding

one (Nybe et a/., 1999). However Karimunda, Narayakodi, Kuthiravali,

Cheriyakaniyakkadan, Kumbhakodi, Karivilanchi, Perumkodi, Kalluvalli, Balankotta and

Uthirankotta are also predominant in the State (Gangadharan, 1998a). Appendix VI

represents cultivar diversity of black pepper in lndia.

Black pepper is traded under Agmark in the name of pepper grades. Standard grades

prescribed under the provisions of Agricultural Produce (Grading and Marketing) Act 1937

are as follows

I Garbled Pepper - Tellichery Garbled Special Extra Bold (TGSEB)

Tellichery Garbled Extra Bold (TGEB)

Tellichery Garbled (TG)

Malabar Garbled (MG-1 and MG-2)

II Ungarbled Pepper - Malabar Ungarbled (MUG-1 and MUG-2)

Ill Light Pepper - Garbled Light (GL-Special, GL-1 and GL-2)

Ungarbled Light (UGL Special, UGL-1 and UGL-2)

IV Pinheads - Pinheads (PH Special and PH-1)

Around 90% of the total export is of Malabar Garbled grade. Common

internationally reputed grades other than MG-1 are Lampong, Sarawak and Brazil named

after the country of origin. Agrnark grades are based on physical characters only, like size

of the berries and presence or absence of contaminants. The factors that decide these

properties are the stage of harvest and post-harvest processing other than, the cultivar

and agronomic practices.

The post-harvest processing of black pepper comprise threshing, blanching,

drying, cleaning, grading, and packaging. Each step is important: but drying is the most

crucial step for attaining quality and storage life. Open sun drying method is prevailing in

Kerala. Mechanical drying, electrical drying, and solar drying are in limited use.

Harvesting of pepper is done by manual picking of spikes containing unripe, but

mature berries. Appearance of red or yellow colour in any of the berries of a spike

indicates optimum maturity of that spike. For the production of black pepper, harvesting is

done at this stage, while fully ripe berries are apt for white pepper production.

Govindarajan (1977) reported that the practice (harvest at maturity) has been changed

and the harvesting is done at different stages of maturity to meet specific requirement of

end product. Harvested spikes are usually kept undisturbed for 24 hours or two days to

ease threshing. In threshing spikes are put together and trampled under the foot to

10

,.-. .-.- .-. .- -- separate the berries. Remarkable investigations on threshing, &'hi'e&d 'for $epper

have been made (Ismall, 1984; Madasami and Godandapani, 1 8?) The ftweshed berrie 1 / \ \

are subjected to 'blanching', i.e. they are dipped in boiling

These are then dried. In open sun drying method drying

depending upon the climatic conditions (Krishnamurthy, et a/., 1993). Dried berries are

collected and cleaned. The common method of cleaning is winnowing. Various types of

'cleaners' have been developed to do this process (Madasami and Godandapani, 1996).

The dried and cleaned product is stored in gunny bags for marketing.

Traditional methods of pepper processing and post-harvest operations have a lot

of problems. Unhygienic techniques and mishandling of the crops most often leads to

contamination and low quality produce (Mamrnootti, 1999). It has been reported that open

drying of berries results in contamination by dust, bits of reeds, stalks, bird droppings etc.

(Sreekumar, 2001). Moreover as the drying period prolongs there is chance of microbial

contamination. The delay in drying time and degree of microbial contamination can easily

affect the aroma quality though no great changes may occur in the physico-chemical

characteristics (Govindarajan. 1976). Generally farmers dry pepper only to a moisture

level of 16-18% instead of the standard 11-12%. Quite often, the produce supplied by the

farmers is not properly dried, cleaned, graded or packed according to recommended

standards.

Pepper drying can also be done using solar dryers, but prevailing solar dryers

have limitations. Considerable studies have been conducted by Shukla and Patil (1992)

on various dryers and drying technologies for food crops. They suggested that in black

pepper, lot of importance is given on the glossy finish. However pepper is grown in coastal

region, where quality deterioration due to fungus on dried product is quite evident.

Intensive research on drying principles and dryers has been carried out in India (Patil,

1989; Palaniappan, 2000).

Hot air drying of pepper developed in Sri Lanka is also recognized as outstanding

method (Abeysinghe, 1982). In this method berries are dried in a hot air dryer at 110-

117°F after blanching for 2-3 minutes, until all the moisture is removed. Various drying

methods including artificial and solar drying prevail in Indonesia, Brazil, Malaysia and Sri

Lanka (Jacob et a/., 1985). However specific studies on black pepper drying for quality

improvement are lacking.

The foremost value of pepper is its flavour, aroma and pungency. The quality is

attributed by its volatile oil, oleoresin and piperine in general. Moisture content and level of

physical contaminants are also important while analysing export quality. According to

Pruthi (1993) the alkaloid piperine is considered to be the major constituent responsible

for the biting taste of black pepper. Retention of piperine, volatile oil and oleoresin is the

prime criteria to be conceived while drying. In this investigation, the quality retention of

pepper following the conventional post-harvest processing and solar tunnel drying is

assessed. An extensive survey of pepper cultivation in Kerala and the quality of the

commercial product is also conducted.

2.2 Materials and Methods

2.2.1 Taxonomy of P i ~ e r niarum Linn.

Division : Angiospermae

Class : Dicotyledons

Sub-class : Monochlamydeae

Series : Micrembryae

Family : Piperaceae

Genus : Piper

Species : nignlm

Origin of the species : Evergreen forests of South-Western ghats of lndia

Habitat :Moist parts of Southern India (North Kanara to

Kanyakumari), Indonesia, Malaysia, Sri Lanka, Brazil,

Vietnam and some other tropical countries

Habit : Climbing perennial shrub with five different types of

branching. Branches stout, trailing and rooting at the nodes;

leaves entire, variable in breadth, sometimes glaucous

beneath, base acute, rounded or cordate, equal or unequal;

flowers minute in spikes, usually dioecious but the female

bears two anthers, and the male, a pistillode; fruiting spikes

variable in length and robustness, rachis glabrous, fruits

ovoid or globose, bright red when ripe, seeds usually

globose, testa thin, albumin hard.

Climate : Humid tropical climate (Relative humidity - above 50%)

with adequate rainfall and tempsrature (10-40°C)

Soil : Clayey loam, red loam, sandy loam and laterite soils with pH

4.5 - 6

Distribution in lndia : (1) Coastal and midland area where pepper is grown as

homestead crop

(2) Hilly regions of Western Ghats

(3) High altitudes (intercrop with coffee and cardamom)

(4) As a mixed crop with areca in plains

(5) Malanadu areas of Karnataka

Flowering season : June - August

Pollination : Geitonogamy aided by rainwater and dew drops

Harvesting season : Plains - November to January, Hills -January to March

Morphology of the useful part . Fruit berries

Major products derived from pepper plant: Black pepper, white pepper and green

pepper

2.2.2 Survev of pepper production in Kerala

An extensive survey was conducted throughout Kerala State by visiting the major

centres of cultivation. Data were collected from the farmers on agro-climatic factors and

p o s t - h a ~ e ~ t processing. The questionnaire used for the field survey is given in appendix

VII.

2.2.3 Sample collection

Ripe berries of black pepper were collected directly from the farmers of different

sampling stations. These sampling stations were located in the 14 districts of Kerala State

(Fig. 1). Sampling was done during 1998 November to 1999 March (season one) from 34

sampling stations. As the farmers prefer to cultivate different cultivars samples collected

were an assortment of different varieties.

2.2.4 Selection of samplinq stations

The number of sampling stations in each district was identified on the basis of

stratified proportional random sampling method (Cochran and Cox, 1957), where yield

was taken as the population. Percentage of sampling was taken at a level of 1%

significance. The following formula was used to identify the sampling stations for different

spices within the districts.

Tamil Nadu

trwambad P I 1

9" - P27 Pul all P I 2

P28 Sunhan BaUm P29 P70 YI

75" I I

Fig. 1 : District Mse map of Kerala showing sampling stations selected for black pepper

Number of stations in a district = 1% sum of yields (of district) X Yield of district

Sum of yields

Stations (PI,P2,P3 .. . ... ... ... P34) were identified for sampling

The ripe berries collected from each station was weighed and divided into three

subsamples. Out of this two sub-samples were packed separately in clean polythene bags

and transported to the research centre within 1-7 hours depending upon the distance. The

third subsample was kept with the farmer for commercial processing.

2.2.5 lnitial moisture content determination

The initial moisture content of black pepper is expressed in percentage by weight

on wet basis. The formula adopted for the calculation is given below.

Initial moisture content (IMC) = Wm x 1 0 0

where,

Wm = weight of moisture evaporated

Wd = weight of dry pepper

But as for every hygroscopic material dried black pepper retains some moisture. It is

called final moisture content. Now the formula is modified as (iMC) = Wm+Wfm x 100

where,

Wfm = weight of final moisture, which is calculated analytically by toluene

distillation method (Dean & Stark) after drying

2.2.6 Ex~er iments on drvin~ of DeDper

Three different drying experiments were conducted for each sample to determine

the drying efficiency through each method. Methods employed for drying were the

following.

a. Drying experiments conducted in solar tunnel dryer (tunnel dried sample)

b. Conventional method of drying conducted in the research centre (conventional

sample)

c. Conventional processing by farmers (commercial sample)

15

2.2.7 Drvina experiments conducted in solar tunnel drver (tunnel dried sample)

Pre-drying treatments

Threshing :- Harvested berries (collected in the form of spikes) were heaped in a clean

room for 24 hours to ease despiking. Threshing was done manually and the berries were

gathered.

Cleaning :- The stalks were removed and the samples sieved through a 4 mm sieve to

remove debris. The samples were then washed in running tap water and heaped up to

drain.

Blanching :- The cleaned berries were taken in a perforated bamboo basket and dipped

in water heated to near boiling temperature (85-90°C) for exactly one minute. After

blanching the berries were kept in clean perforated bamboo basket for one hour to drain

excess water.

Solar tunnel drying was done in an imported 'solar tunnel dryer' developed by

Esper and Muhlbauer (1996), installed at the Botany research centre of Sacred Heart

College. The solar tunnel dryer developed at the Institute of Agricultural Engineering in the

Tropics and Sub-tropics of Hohenheim University, Germany consists basically of a plastic

foil covered flat plate solar air heater, a drying tunnel, and small axial flow fans (Fig. 2,3,4

and plates 1,2,3). These three fundamental structures are connected in series. The floor

of the entire system consists of a few blocks connected by groove and tongue system.

Each block is made up of plastic form sandwiched with metal sheets. Floor has a

thickness of 3 cm. This system is erected on concrete blocks of 47 cm height. The plastic

foil covering of the dryer is transparent UV stabilized plastic film of 0.2 mm thickness. To

prevent the entry of water during rain, the cover foil is fixed l i ~ e a sloping roof at an angle

of 15O. The solar tunnel dryer has a length of 17 m (10 m for the tunnel and 7 m for the

solar air heater) and a breadth of 2 m. Length can be adjusted according to the

requirement. The whole system is placed horizontally on the ground since the tilting of the

collector is not essential for improved drying performance (Bala et a/., 1997). Two small

DC fans operated by one photovoltaic module provide the air at required flow rate.

The floor of the solar air heater is coated with black paint, which facilitates 90%

absorbtivity. On the other hand tunnel surface is painted with white colour to reflect the

solar radiations. A wire mesh lined with plastic net is provided in the tunnel for spreading

the crop. This system furnishes a 20 mm height to the crop-spreading surface (plastic

net), so that a maximum surface area will be exposed to hot air current. Tunnel area is

also provided with opening and closing system. Capacity of the tunnel ranges from 50 kg

to 200 kg wet products in the case of spices. But this depends upon size, weight, moisture

content of the spice, and thickness of spreading layer.

Principle of Drying in Solar Tunnel Dryer

During drying, air inside the solar tunnel dryer gets heated up by the solar radiation

coming through the plastic foil. The heater absorbs incoming radiations, whereas in tunnel

the entering radiations are all reflected since the floor is white in colour. Due to 'green

house effect' reflected solar rays cannot go out through the foil. So the temperature inside

the dryer rises up. Within a short period of time temperature of the dryer goes up by 200 -

250% of the ambient air. By the action of axial flow fans fresh air enters the heater

simultaneously. The entry of fresh air makes a pressure inside the dryer, resulting in

continuous flow of hot air inside the tunnel area in the form of circular air currents.

Intensity of incident solar radiation (insolation), temperature and relative humidity of the

ambient air are the chief factors influencing rate of drying.

Drying ofpepper

After pre-treatments the berries were spread in the tunnel in one fruit thickness. No

overlapping and clustering were allowed. Dryer was closed by steering down the pedal

carrying plastic foil, and allowed the samples to dry. Temperature and relative humidity of

the dryer and ambient air were monitored at one-hour interval, starting from 8 a.m. to 6

p.m. Mercury thermometer and an air guide instrument (USA) were used for the

measurement of temperature and relative humidity respectively. The intensity of solar

radiation was measured by placing a pyranometer at an angle of 1 5 O similar to the plane

of solar module. Readings taken from the dryer is the average of three measurements

noted from different spots viz. junction of solar air heater and drying tunnel, middle of the

tunnel and at the outlet of the dryer. To provide a more or less uniform drying condition

and to develop uniform colour the berries were turned at every one hour interval. The

completion of drying is confirmed by the characteristic metallic sound made by gentle bite.

Immediately after drying berries were gathered inside the dryer into a heap. Dry

weight of the samples was taken, and amount of spice recovery was calculated as follows.

Spice recovery = Wd x 100

where,

Wd = weight of dried black pepper

Wp = weight of wet black pepper

Post-drying treatments

Dried berries were cleaned to discard the unwanted materials. It was sifted to and

fro within the spreading net inside the dryer. This was done immediately after drying.

Cleaned berries were then collected in a plastic bag. Random subsamples were taken in

triplicate for conducting physico-chemical quality analyses. Remaining samples were kept

in gunny bags lined with black polythene sheet. The gunny bags were stored in dry place

to avoid remoistening and to facilitate uniform moisture content.

2.2.8 Conventional method of drvina conducted in the research centre (conven-

tional sample)

Second sub-samples collected from each station were dried under conventional

method. Open sun drying method in a scientific way was employed for this drying. This

was done simultaneously with tunnel drying.

Harvested pepper spikes were kept for 24 hours in a room. After that threshing

was done by trampling. Stalks and detached berries were separated. The berries were

gathered to heap. Without any further treatments the berries were spread on a bamboo

mat. Turning the spread layer was done every evening. Completion of drying was

understood by manual method. After drying, the berries were taken and kept in gunny

bag. Subsamples were taken in triplicate at random for quality evaluation.

2.2.9 Conventional processina bv farmers (commercial sample)

A third type of drying was conducted with the subsamples kept with the farmers

during sampling. This drying was done by the farmers of the plantations, from where the

samples were collected. They dried the samples in the routine drying method, This

method was adopted to understand the quality of commercially available samples. For the

quality evaluation, sub-samples were taken at random in triplicate from the dried pepper.

2.2.10 Rewetition of exweriments

The drying experiments were repeated for one more season to find out the

reproducibility of the results. These experiments were conducted during November 1999

to March 2000 (second season). Samples were collected from only 14 stations out of the

previously studied 34 sampling sites such that each station represented a particular

district. The stations selected were the locations of the highest yield. Same methodology

was adopted for the sampling, drying and quality evaluation of pepper in the repetition

experiments also.

2.2.1 I Quality evaluation of pepper

Chief export quality parameters of black pepper are categorized under two heads

viz. chemical and physical. In this investigation physical quality parameters were

conducted by adopting internationally accepted specifications formulated by ASTA

(American Spice Trade Association), USFDA (United States Food and Drugs

Administration) and Agmark (India). Analytical methods recommended by AOAC

(Association of Official Analytical Chemists) under the supervision of ASTA were used for

conducting chemical quality analyses. These quality determinations were carried out with

all the dried subsamples collected after each post-harvest experiment. Quality analyses

were done at the quality evaluation and upgradation laboratory of Spices Board, Kochi

and at the research centre, Botany Department, Sacred Heart College, Thevara. The

analytical procedures of ascertaining the quality of black pepper are given below.

No Nameof specification +- Parameters Studied

I. ASTA analytical

methods (ASTA,

1997)

a.

Chemical

Moisture (% by weight)

b.

Methodology I

Volatile oil (% v/w)

c.

d.

Toluene Distillation

(Dean and Stark)

Oleoresin (% by weight)

Piperine (% by weight)

Hydrodistillation

(Clevenger)

Solvent extraction

(Soxhlet)

UV-spectrophotometer I ,

Phvsical 1 Asta Cleanliness

Specification

(ASTA, 1998)

Whole insects d'ead (by count)

Excreta mammalian (mgllb)

Excreta others (mgllb)

Mold (% by weight)

Insect defiledlinfested

(% by weight)

Extraneous/foreign matter

(% by weight)

' Manual counting

'1 Sieving and weighing

'2 Picking &weighing

'3 Picking 8 weighing

*4 Sieving &weighing

I I fications for spices I b. I Light berries (% by weight) 1 '6 Floatation method I 3.

The sample size selected was 1 pound (4 kg). Sub-samples at random were

Agmark grade speci-

I

taken from the lot for conducting quality analyses and reduced the size into 50 gm by

(Anonymous, 1996)

coning and quartering method.

a.

Counting the total number of dead insects from the representative sample (% to 1

Phvsical -1 Pin heads (% by weight) / *5 Sieving &weighing 1

pound)

*I Sieved the sample through a sieve (US No 8) and sort out all the mammalian excreta

Calculate the quantity in terms of pound

(Excreta mammalian = weight of excreta x454)

sample weight x I lb

*2 Pick all the moldy pieces (%Ih moldy) from the sample and calculate the percentage by

weight

20

'3 Pick all the insect infested pieces (%Ih infected) from the sample and calculate the

percentage by weight

'4 Sieve the representative sample through a US No 8 sieve. Collect all the matter settle

down during sifting, remove pinheads and take weight. Calculate the percentage by

weight difference.

'5 After passing the sample through the US No 8 sieve, pick all the pinheads. Calculate

the percentage by weight.

'6 A known weight (50 gm) is immersed in 350 ml of 95 % alcohol for 2 minutes. Stir well;

light berries float on the surface. Take them, blot and dry. Calculate the percentage by

weight.

Procedures adopted for the analyses of chemical parameters studied are given below: -

Final Moisture Content (Distillation method)

Determination of moisture content of dried pepper was carried out by toluene co-

distillation process using Dean & Stark apparatus. 25 gm of ground sample was weighed

and transferred into a 500 ml round bottom flask (distillation flask). Approximately 75 ml of

the solvent (toluene) was poured into the flask so as to cover the sample completely. The

moisture distillation apparatus was assembled, and the trap was filled with toluene by

pouring through the condenser (Liebig condenser). A loose non-absorbent cotton was

inserted at the top of the condenser to prevent condensation of atmospheric moisture in

the condenser. Started boiling and refluxed at about 2 drops per second until most of the

water had been collected in the trap. The reflux rate was then increased to 4 drops per

second for about 15 minutes until two consecutive readings showed no change. The

condenser was rinsed with 5 ml of toluene. Refluxing was continued for 5 minutes more.

The trap was cooled to 20°C in a water bath. It took one hour to complete the analysis.

The percentage moisture content was calculated using the following equation.

Moisture, % = Volume of water (mu x 100

Weight of sample (g)

Volatile oil (Modified Clevenger method)

The amount of volatile oil was determined by modified Clevenger method. 10 grn

of ground sample was weighed out and transferred quantitatively into a 500 ml round

bottom flask of the volatile oil apparatus. Flask was filled with sufficient quantity of water.

Then the trap was fixed on the flask and filled with water. Cotton plugged condenser was

connected and the whole system were fixed onto a stand. Flask was heated to boiliqg and

a reflux rate of 1-2 drops per second was maintained. Continued the refluxing until two

consecutive readings taken at one-hour interval showed no change of oil volume in the

trap. It took about 2% hours to complete the process. The system was allowed to cool.

The percentage volatile oil content was calculated using the following equation

Volatile oil, % (vlw) = Volume of oil (ml) 25OC x 100

Weight of sample (g)

Oleoresin (Solvent extraction method)

Oleoresin of black pepper was determined by ethylene dichloride (EDC) extract

method using soxhlet apparatus. Two grams of ground sample was weighed and put into

a paper extraction thimble, a cup made of whatman 1 filter paper. The thimble, containing

sample was placed in the container of the extractor. Condenser was fixed onto it. The

apparatus was assembled and started the extracting with ethylene dichloride as solvent.

Extraction extended to 20 hours. After the process the extract was transferred into a

beaker quantitatively. On a steam bath the solvent was evaporated completely. When the

last traces of EDC was evaporated, the container was placed in a hot air oven at

llOoG!oC until two consecutive weighings taken at I Y ~ h o u r intervals didn't differ by more

than 1 mg. The dried residue is the non-volatile ethylene dichloride extract (oleoresin).

Percentage of oleoresin was calculated using the following formula

Oleoresin, % = Weight of residue x 100

Weight of sample

Piperine (uv-spectrophotometer method)

Piperine content of dried pepper was determined by using a uv-

spectrophotometer. Finely ground pepper sample (as per the specification of AOAC) of

0.5 grams was taken in a 125 mL flat bottom flask (Erlenmeyer flask) and allowed to reflux

with 70 mL of Standard Denatured Alcohol (SDA) N0.3A (l:20-methyl alcohol and 95%

ethyl alcohol) for one hour. The flask was covered with aluminium foil to protect piperine

from light. After refluxing, the system was allowed to cool to room temperature. Filtered

the mixture into a 200 mL volumetric flask and made up to the volume. 4 ml of the solution

was further diluted to 100 mL. Using SDA No.3A as the reference solution, absorbance

was measured at 343 nm within 15 minutes using a Hitachi spectrophotometer.

Percentage piperine was calculated using the following equatioq.

Piperine, % = [(A.xF~v)~,~Io~)]x 100

Where,

As = absorbance of the sample

F = factor derived from Piperine

V = dilution volume, milliliters

W. = sample weight, grams

2.2.12 Data Analvses

Survey results were tabulated and analyzed. Results of all the quality parameters

were computed with the help of windows excel computer programme. The different drying

methods were evaluated in terms of the product quality by ANOVA. The significance of

the difference between the treatment means was further confirmed by estimating the

critical ratio between the pairs of treatment means (Rao and Richard, 1998). The product

quality data of the samples of consecutive years (season one and season two) were also

compared using students t test.

2.3 Ob~e~ati0n.S and Results

2.3.1 Observations on oeoper production in Kerala

The survey conducted during the study revealed the following: -

Type of soil

Thiruvananthapuram : Sandy, red and loose soil with enough moisture

Kollam : Red soil mixed with sand and good drainage

Pathanamthitta : Black soil with enough drainage

Alappuzha : Sandy loam with good drainage

Kottayam : Laterite and top soil

ldukki : Top soil black and bottom red

Ernakulam : Red and fertile soil.

Thrissur : Fertile and sandy loam soil

Palakkad : Laterite soil

Malappuram : Any soil with good drainage

Kozhikkod : Laterite soil

Wayanad : All types of soil with enough drainage

Kannur : Laterite soil

Kasaragod : Red soil.

Method of planting

The planting material is rootless cuttings of pepper vine or rooted nursery cuttings.

The stem cuttings are collected from 2-5 year old mother plants. Stem cuttings of 10

nodes are employed for planting, of which at least 3-5 nodes are kept below the soil.

Planting is done on the northern side of the standards in order to avoid direct hot wind

from the southern side during summer. The planting standards in common use are jack

fNit, Coconut, mango, cashew, areca nut, ailanthus, shorea, teak, macaranga, thespasia,

moringa etc. Trees like bombax; erythrina and other smooth skinned trees are planted one

year before pepper planting to be used as planting standards. In some localities of

Palakkad district, Karimpanas (Borassus flabellifer) are also used for this purpose.

According to farmers 30-40% improvement of pepper yield IS noticed when these plants

are used as planting standards. Concrete pillars and wood logs are also used as non-

living planting standards.

Cultivars

Survey results revealed that 41 cultivars are used regularly in various parts of the

State. These are listed below.

Thiruvananthapuram : Karimunda (most popular), Vellamundi, Panniyur I,

Narayakkodi, Pala, Kottanadan, Padappan, Attamurian.

Kollam : Karimunda, Pala, Aimpirian, Panniyur I, Padappan,

Chemparathi, Vellaramundi, Kariyilanji, Vallamunda.

Pathanamthitta : Narayakkodi. Kotta, Panniyur I, Karimunda (not so popular),

Chumalakkodi

Alappuzha : Karimunda, Panniyur I, Kuthiravalan, Nadan, Kariyilaanji.

Kottayam : Karimunda, Panniyur I, Elamunda, Narayakkodi

ldukki : Chengannurkodi, Vellanamban, Karimunda, Vellaramunda,

Geerakamunda, Panniyur I, Kathiravalli, Neelamundi,

Vattamundi, Yohannankodi, Varkakodi, Ambaramunda,

Kaniyakkadan, Thevamundi, Marampadathi, Attamurian,

Narayakkodi

Emakulam : Karimunda, Panniyur I, Vellanamban

Thrissur : Karimunda, Kuthiravalan, Panniyur I, Valiyakodi, Kaniyakkadan,

Cheriyakodi, Kariyamunda, Narayakkodi

Palakkad : Panniyur I, Panniyur II, Karimunda, Chettan, Nadan,

Arakkulam, Geerakamundi. Kuthiravally. Kuppakkodi,

Narayakkodi

Malappuram : Panniyur I, Karimunda, Nadan valli, Chettan

Kozhikkod : Karimunda, Panniyur I, Arakkalamunda, Pewmkodi.

Narayakkodi, Kaniyakkadan

Wayanad

Kannur

: Karimunda, Arakkalamundi, Panniyur I, Wayanadan,

Balankotta, Karimkotta, Aimpirian, Geerakamundi,

Valiyamaniyan, Nadesen, Vellanamban, Valamkotta, Kalluvalli,

Valiyarkulam, Cheriarkulam, Perumkodi, Neelarnundi

: Sreekara, Shubhakara, Panchami, Pournami (Aralam Farm);

Panniyur I, Karimunda, Arakkalamunda, Karimkotta,

Kuthiravally, Kottanadan, Cheriyakaniyakkadan,

Valiyakaniyakkadan, Arivally, Balankotta, Narayakkodi

Kasaragod : Nadan, Chettan. Karimunda, Panniyur I, Kotta, Kalluvalli.

Cropping methods and spacing

In Kerala black pepper is commonly cultivated as an intercrop. However pure

plantations of pepper are also seen in some areas of Wayanad, Kannur and ldukki

districts. lntercropping partners are coconut, areca nut, coffee, cashew etc. Mixed

cropping system is also reported from Wayanad and ldukki, where pepper is grown along

with vegetables and other annual crops.

No unified spacing for pepper plants are available in Kerala since the pattern of

cultivation is not pure in most places. Different spacing measurements availabie for

pepper plantations are 2mX2mX2m, 3mX3mX3m, 5 feet X 5 feet X 8 feet or 9 feet X 9

feet X 9 feet. A minimum distance of l m is provided between the rows and lines in any

pepper garden.

Time of planting

Farmers prefer the onset of southwest monsoon as the time of plant~ng i.e. during

June and July months. Rarely farmers belonging to coastal zones of Alappuzha choose

October and November months i.e. during the northeast monsoon as the time of planting.

Manuring

Chemical fertilizers used for pepper are MOP (muriate of potash), factamfose,

17:17, complex fertilizers, urea, massurifos, potash etc. Generally farmers apply manure

twice in a year, which are usually during the onset of monsoons. Dried cowdung and bone

meal are also applied to plant base at the annual rate of 5 kg, and 500 gm respectively

every year. Farmers of ldukki and Wayanad districts apply only dried cowdung (@I0 -15

kglplant.year). Almost same method is adopted in the areas of Thrissur by replacing cow

dung with bone meal. Large number of other combinations is also prevailing in Kerala.

Recently farmers have adopted a practice of growing pepper through organic farming.

Organic farms of pepper occur in Kumili, Peewmed, Cherthala, Thodupuzha, Kalady,

Thimvambady, and some parts of Wayanad district. Organic manures commonly

employed are cow dung, farmyard manure, bacterial compost, vermicompost, neem cake,

groundnut cake, bone meal, and ash.

Farming operations

During the initial stages of growth, pepper plant is protected from sunlight by

covering the cutting with palm leaves or any other shade giving leaves. Base of the plants

are covered with mulch of dried leaves. Up to third year of planting some farmers tie the

plant along with coconut fronts during summer to protect from heat. A method prevailing in

ldukki district has got enough attention among the farmers. Runner shoots and other

hanging branches of the plant are pushed to the base and covered with soil. Each branch

would become a new plant and results in the formation of 10-15 plants in a support. In

Wayanad farmers cover the base with soil like a stalk less funnel. Some farmers tie the

cutting with leafy plants on to the support until the roots are established.

Time o fflowering

Flowering season varies according to the altitude and climate. Flowering starts by

the middle of May and extend up to August or even up to September. In plains the

flowering season is early and ends accordingly, whereas it is late in hilly areas.

Pesticide application

Prophylactic measures are absent in general, but farmers of Wayanad, ldukki and

certain prospective farmers of other districts do apply pesticides. Appl~cation of bordeaux

mixture is the only uniform method in the State. This is done before the commencement of

southwest and northeast monsoons every year. Copper oxychloride (COC) for basal

application, ekalux, emisan, monocrotophose, and roger are the other common pesticides

used in Kerala. However bordeaux mixture accounts for more than SO%, and farmers still

trust in its healing power than any other chemical medicines. Majority of the farmers

neither adopt any plant protection measures nor are aware of scientific treatments.

Tobacco decoction, neem oil, ash and cow dung paste are the common organic pesticides

used in some places. Application of Trichoderma and Pseudomonas (100 gm dust in 10

litre of water, aerial spraying) are also employed in some farms of Erattupetta and ldukki.

Dkeases

Quick wilt caused by Phyfophthora capsici remains the chief disease until now

even though the development of agriculture attains new dimensions. Large number of

plants are destroyed every year due to the uncontrollable attack of this fungi. Slow wilt

caused by a group of pathogens (Fusanum sp., Rhizoctonia sp., Diplodia sp., Pithium sp.,

Radopholus similes and Meloidogyne incognita) is also responsible for severe losses.

Yellowing, wilt and pollu diseases are common in eastern parts of Thiruvananthapurarn.

Except for root borer, 'Munja' (White fly) no other observable illness are reported in some

regions of Kollam district since last 10 years. In Pathanamthitta farmers are in trouble with

foot rot and falling of berries. Large number of plantations were destroyed due to quick wilt

during 1998-1999. Incidence of quick wilt, stem rot, root rot, and berry falling are not so

uncommon in ldukki district. In Wayanad more than 50% of the pepper plants were

devastated due to quick wilt. However gardens without the incident of any disease also

occur in some areas of Alappuzha, Palakkad, Emakulam, Malappuram, Kozhikkode and

Kannur districts.

Harvesting season

There is only one season for pepper harvesting. This starts from November and

ends in April. The plants are ready to hawest by December in plains, and January in hilly

areas. Harvesting season of high ranges is always late.

Method of tzarvesting

Farmers detect the maturity of the spike by observing the colour of berries.

Harvesting is done when one or a few berries turn red or yellow in colour. Only manual

harvesting is prevailing in Kerala. With the help of ladders and bamboo twigs farmers

pluck the spikes by hand. Selective, and complete harvesting is practiced. In the former

case only fully mature spikes are plucked so that 3 or 4 harvests at an interval of 15' days

is needed for completion. In the latter case the entire spikes are harvested without any

selectivity. Harvesting is also done based on certain requirements, such as for the

production of pickles, extracts and other value added products.

Yield of blackpepper

Yield of pepper varies from place to place. 2-3 kg of dried pepper is obtained from

a single plant in Pathanamthitta. An yield of 30-50 kg green pepperlfive year old plant is

reported from Chithara, Kollam, 5-10 kg greenlplant in Poovachal, 0.5-1 kg dried

pepperlplant in Thiruvambady, 3 kg dried pepper in Malappuram, 1000 kglhectare in pure

plantations of Pulpally, 10 kglplant in Sulthan Bathery, 2 kglpiant in Kasaragod. 3-4

kglplant in Kottayam, 10 kg/plant in Aralam farm, 0.35-0.5 kglplant in Angamaly, and 20

kglplant in Mavelikkara.

Post-harvest operations

Pre-drying treatments: - Threshing is done by trampling with human foot, after storing

the harvest for one or two days in open room. Some farmers of ldukki district use Paddy

thresher. In some areas, farmers of small gardens do not despike; but dry directly by

spreading the spikes on the ground. Blanching is done by at least some progressive

farmers. They soak berries in boiling water for 1-10 minutes (15 minutes in Chithara).

Some farmers believe that blanching reduces recovery. There are some farmers, who

separate the yield into mature, and ripe berries, then dry the mature berries and put the

rest into white pepper production. The processors belonging to Pathanamthitta and

Alappuzha districts also do cleaning and sieving. In general such pre-treatments are

carried out without threshing.

Drying operations: - Open sun drying method is prevai!ing in Kerala. Spreading the

berries on cement floors, terraces, bamboo mats, cow dung coated bamboo mats, plastic

sheets, tarpaulins, paddy drying fields, rock surfaces, raised platforms or even soil

surfaces are the methods followed. Thickness of the spreading layer is uneven with

clusters and overlapping. Respreading the crop is done some times but not regularly. In

southern districts drying is conducted on roadsides. Smoke drying is also done in some

areas when it rains. In some parts of the State after the second day of drying berries are

kept in plastic bags and a rock is put on the bag to apply pressure. It is spread again the

next day for drying. It takes 3-7 days for complete drying depending on the weather. The

completion of drying is confirmed by the characteristic metallic sound made by a gentle

bite.

Spice recovery varies according to the variety, maturity and drying practices. In

general one third is obtained from fully mature crop. One fourth, and 112.5 are recovered

from under-matured, and ripe berries respectively. Some old varieties with 40% recovery

were not rare in Kerala; but now they are under the threat of extinction.

Post-drying operations: - In Kerala post-drying treatments are always done by the

processors and merchants. After drying, pepper is usually marketed as ungarbled black

pepper. Very few subject the dried berries to winnowing or remove the stalks and other

unwanted materials. Sieving and sorting into light berries, half pepper, pinheads and

pepper are also done by a few.

Storage

Storage of pepper is done only when the price is low compared to the price of the

previous year. Fungal patches always appear upon storage due to improper drying

especially during the rainy season. Plastic or jute bags or polythene lined gunny bags are

used for storage. Sometimes wooden platforms are raised for arranging pepper bags.

According to a farmer of Karimba, Palakkad, biscuit tins may be employed; but plastic

bags are not ideal. According to experts black pepper can be stored up to a period of six

to ten years without any considerable damage in airtight bags. In general storage is

influenced by the method and extend of drying carried out by the farmer. , .

2.3.2 Results of the drvina ex~er iments (season 1)

Daily average of solar radiation, temperature, and relative humidity of ambient air

and within the tunnel dryer measured during the drying of black pepper in solar tunnel

dryer are represented graphically (Fig. 5 to 7).

Time (Hours)

Fig. 5: Daily average solar radiation during the drying of pepper in Solar Tunnel Dryer

The intensity of the solar radiation increased from the morning to noon, reached a

maximum at 12 noon, remained almost stable till 2 p.m. and then gradually decreased by

5 p.m. The maximum solar intensity recorded was 910 W/m2 and the minimum 183 W/m2.

IP

-+Ambient Ai -A- Dryer I0

T i m (Hours)

Fig. 6: Mean daily temperature of ambient air and solar tunnel dryer during the drying of - - .

black pepper , . .- . . . . . .

.\. ., "

Tim ( H m )

Fig. 7: Mean daily relative humidity of ambient air and solar tunnel dryer during the drying

of black pepper

The temperature inside the dryer varied from 30°C to 70°C during day hours.

Range of temperature noticed in ambient air was 28% to 37OC. Relative humidity inside

the dryer was always less than that of the ambient air. It ranged from 68% to 30% in the

ambient air, and 62% to 21% in the dryer.

Initial Moisture Content (IMC)

The mean initial moisture content of black pepper samples collected from 34

stations is represented in table 1. The average IMC of all stations was 70.4%. Mannuthi

station recorded a maximum of 73% among the 34 stations while Kalady represented the

lowest (68.61%).

Table 1: Initial moisture content of black pepper samples collected from 34 stations

Drying Time

The optimum drying time of pepper as done by the farmers in the 34 sampling

stations varied from 24 hours to 56 hours with a mean value of 39 hours. Conventional

drying of these samples after transporting to the laboratory took 24 hours to 48 hours with

a mean value of 31 hours. In solar tunnel dryer, the drying period varied from 8 hours to

13 hours with a mean value of 10 hours. Statistical analyses of the data (Table 2)'showed

significant difference in the drying period.

Table 2: Time taken for drying of pepper berries collected from 34 stations (PI-P34),

results of ANOVA, and critical ratio estimates of drying of pepper following

three different methods

Spice Recovery

The mean spice recovery of the commercial samples was 37.65%, conventional

37.08% and tunnel dried 33.89%. Out of the three sample groups the lowest spice

recovery was observed in tunnel dried samples. The analysis of the data is given in Table

3.

Table 3: Spice recovery of pepper collected from 34 stations (PI-P34), results of

ANOVA, and critical ratio estimates of drying of pepper following three

different methods

2.3.3 Qualitv evaluation of black pepDer

Final Moisture Content (FMC)

The mean moisture content of dried pepper was 13.58% for commercial samples,

12.64% for conventional and 10.75% for tunnel-dried samples. The moisture content of

commercial and conventional samples varied more than the tunnel-dried samples. The

statistical analysis of the data is given in table 4.

Table 4 :Moisture content of black pepper samples dried under three methods, results of

ANOVA and critical ratio estimates of various treatments

Volatile Oil

The mean volatile oil content of the commercial pc.pper sample was 1.28%v/w;

conventional sample 2.09%vlw and tunnel dried sample 2.19%vlw (Table 5). The sample

from Chithara station recorded the highest percentage of volatile oil content (3.3%) when

dried in solar tunnel dryer. Statistical analysis revealed that the volatile oil content of solar

tunnel dried and conventional sample are similar while that of the commercial sample is

significantly lower.

Table 5: Volatile oil content of black pepper dried according to three different

methods, results of ANOVA and critical ratio estimate of various treatments

Oleoresin

The mean content of oleoresin of 34 commercial samples was 6.59% that of

conventional 6.65% and tunnel dried 7.67% (Table 6). Nedunkandom and Koothattukulam

samples showed highest percentage of oleoresin content (9.1%). Out of the three sample

groups the highest oleoresin content was observed in tunnel dried samples. However

there is no statistical difference between conventional and solar tunnel dried or

commercial and conventional. But the oleoresin content of commercial sample is

significantly lower than solar tunnel dried samples.

Table 6: Oleoresin content of black pepper dried according to the three methods,

results of ANOVA, and critical ratio estimates of different tests

Piperine

The mean piperine content of 34 commercial samples was 4.77% conventional

4.68% and tunnel dried 5.55% (Table 7). A maximum quantity of 6.4% was recovered

from the solar tunnel dried sample collected from Pathanapuram. Statistical analysis

showed that solar tunnel dried sample has significantly higher piperine content.

Table 7: Piperine content of black pepper samples dried under three methods, results

of ANOVA and critical ratio estimates of various treatments

I Piperine (Oh by weight)

Anova: Single Factor - SUMMARY 1 Groups Column 1 Column 2 column 3

Count 34

34

34

Sum 162.1 159

188.6

Average 4.77 4.68 5.55

Vanance 0.62

S. D.

t0.79

0.48 0.22

f0.69

t0.47

Whole Insech Dead

The incidence of contamination was 82% in commercial samples, 68% in

conventional samples, and 47% in tunnel-dried samples. The mean number of dead

insects counted in commercial samples was 4.38, in conventional samples 1.79 and in

tunnel dried 0.71(Table 8). The insect count in commercial sample ranged from zero to

16, and in conventional samples from zero to 6. In tunnel dryer the insect count waS from

zero to 3. Critical ratio estimate showed solar tunnel dried samples to have significantly

low insect count compared to the other two.

Table 8: Whole insects dead count of black pepper samples dried under three

methods, results of ANOVA and critical ratio estimates of various treatments

Excreta Mammalian

Mammalian excreta were present only in commercial and conventional samples;

the incidence was 65% and 41% respectively. The mean of 34 samples was 79.21

mglpound and 18.35 mglpound respectively (Table 9). Out of the three sample groups the

tunnel-dried samples showed no trace of mammalian excreta. The contamination by

excreta was significantly lower in conventional samples compared to commercial.

Table 9: Excreta (mammalian) content of pepper samples dried under different

methods, results of ANOVA and critical ratio estimates of various treatments

Excreta Otliers

Excreta from any other source contaminated none of the samples

Mold was completely absent in solar tunnel dried samples, whereas 100% of the

commercial, and 24% of the conventional samples had mold growth. The mean value of

mold contamination was 2.72% in commercial, 0.17% in conventional, and nil in tunnel-

dried samples (Table 10). The mold infestation was significantly low in the conventional

sample compared to commercial samples as given by critical ratio estimates.

Table 10: Mold content of pepper samples dried as per three different methods, results

of ANOVA, and critical ratio estimates of different tests

Insect defled/in fested

The incidence of insect infestation was 94% in commercial group, 100% in

conventional set, and 41% in tunnel-dried samples. The mean value of dried pepper

infested with insects was 2.69% in commercial, 1.60% in conventional, and 0.14% in

tunnel-dried sample (Table 11).

Extraneoudforeign matter

The contamination incidence was 100% in commercial and conventional samples,

and 94% in tunnel-dried set. The mean value of extraneous matter in commercial sample

was 1.24%, conventional 0.54% and tunnel dried 0.17% (Table 12). Out of the three

sample groups the lowest extraneous matter content was observed in tunnel dried

samples. There was significant difference among treatment pairs as shown by the critical

ratio estimate.

Table 12: Extraneouslforeign matter of black pepper samples dried under three

methods, results of ANOVA and critical ratio estimates of various treatments

Pin heads

Pinhead occurrence in commercial and conventional sample groups was 82% and

56% respectively. In solar tunnel dried samples pinheads were only 29%. The amount of

pinheads in commercial sample was 1.17%, conventional 0.48%, and tunnel dried 0.04%

(Table 13). The quantity of pinheads of commercial sample was highly variable; but

conventional and tunnel dried sample had more uniformity. Out of the three sample

groups the lowest pinheads quantity was observed in tunnel dried samples. Critical ratio

estimate between treatment pairs showed high variation betw?en all the pairs.

Table 13: Pinheads of black pepper samples dried under three different methods,

results of ANOVA, and critical ratio estimates ot various tests

Light berries

Light berries were present in all the samples. The amount of light berries in

commercial sample was 3.20%, conventional 1.33%, and tunnel dried 0.54% (Table 14).

The light berry content of commercial sample was highly variable (variance 3.36), tunnel

dried and conventional samples had more uniformity in light berry content (variance 0.29

and 0.08 respectively). Critical ratio estimate between treatmnnt pairs showed significant

variation.

Table 14: Light berries content of black pepper samples dried under three methods,

results of ANOVA and critical ratio estimate of various tests.

2.3.4 Repetition of drvina experiments and aualitv analvses (season two)

Data on temperature, relative humidity and solar intensity measured during the

drying of black pepper during the second season showed no significant difference. t-test

results of various quality parameters also showed no significant difference between the

results obtained in season one and two (Appendix VIII). The initial moisture content

ranged from 71.9% (berries from Thiruvambady) to 68.7% (at Payyannur). The mean

value was 70.1Y0i0.84

Spice recovery and drying time are represented in tables 15 and 16. The spice

recovery was in the range 33.64% to 37.16%. The least recovery was in the solar tunnel

dried samples. Commercial and conventional samples gave similar yield. The optimum

- ~ - ~ ~ - -~ 45

drying period was 37 hours, 30 hours and 10 hours respectively for commercial,

conventional and tunnel dried samples.

Table 15: Spice recovery from pepper berries collected from 14 stations (Pl-P14),

results of ANOVA, and critical ratio estimates of drying of pepper following

three different methods

Table 16: Drying time taken for pepper berries collected from 14 stations (PI-P14),

results of ANOVA, and critical ratio estimates of drying of pepper following

three different methods

The final moisture content of 14 commercial samples was 13.75%i0.70;

conventional 12.69%*0.47 and tunnel dried 10.85%*0.32 (Table 17).

Table 17: Final moisture content of black pepper samples dried under three methods,

results of ANOVA and critical ratio estimates of various treatments

The volatile oil content of the commercial sample was 1.33%*0.17 vlw,

conventional 2.06Y0k0.14 vlw and tunnel dried 2.28%*0.32 vlw. Out of the three sample

groups the highest volatile oil content was observed in tunnel dried samples (Table 18).

The mean content of oleoresin of 14 commercial samples was 6.94%*0.41 by weight;

conventional 7.19%*0.37 by weight, and tunnel dried 7.65%*0.58 by weight (Table 19).

Table 18: Volatile oil content of black pepper dried according to three different

methods, results of ANOVA and critical ratio estimate

Table 19: Oleoresin content results of ANOVA, critical ratio test conducted after drying

of pepper in three different methods

The mean piperine content of 14 commercial samples was 4.4%+0.32;

conventional 4.68%+0.42 and tunnel dried 5.66%+0.36 (Table 20).

Table 20: Piperine content of black pepper samples dried under three methods, results

of ANOVA and critical ratio estimates of various treatments

All the samples dried under commercial method contained dead insects. There

was 64% in conventional samples and 36% in tunnel-dried samples. The mean number of

Table 21: Whole insects dead count of black pepper samples dried under three

dead insects counted in commercial sample was 6.86, in conventional samples 1.71 and

in tunnel dried 0.36 (Table 21). Out of the three sample groups the lowest whole insects

dead count was observed in tunnel-dried samples.

Mammalian excreta were present only in commercial and conventional samples;

the incidence was 79% and 57% respectively (Table 22). The mean of 14 samples was

12.66 mgllb and 26.86 mgllb respectively

Table 22: Excreta (mammalian) content of pepper samples dried under different

methods, results of ANOVA and critical ratio estimates of various treatments

'Other excreta' was absent in all the samples dried under different methods.

Cent percent of commercial set and 50% of conventional group had mold growth.

The contamination by mold was nil in solar tunnel dried samples. The mean of 14 samples

drawn from the commercial outlets was 3.51% and conventional 0.11% (Table 23).

Table 23: Mold content of pepper samples dried as per three different methods, results

of ANOVA, and critical ratio estimates of different tests

Almost all the samples processed under commercial and conventional method had

insect infestation (93% in commercial and 100% in conventional); but in the case of

tunnel-dried samples the incidence was only 7% (Table 24). The dried pepper infested

with insects was 1.26% in commercial, 1.59% in conventional, and 0.01% in tunnel dried.

Table 24: Insect defiled/infested berries of black peppel samples dried under three

methods, results of ANOVA and critical ratio estimates of various tests

Extraneous matter was frequent in all the pepper samples; but tunnel dried

samples showed the least. The mean value of extraneous matter in commercial sample

was 1.37%, conventional 0.58%, and tunnel dried 0.16% (Table 25).

Table 25: Extraneousfioreign matter of black pepper samples dried under three

methods, results of ANOVA and critical ratio estimates of various treatments

Pinheads were present in all commercial and conventional samples. The

occurrence was only 43% in tunnel-dried set. The mean amount of pinheads in

commercial samples was 1.17%, conventional 0.51% and tunnel dried 0.08% (Table 26)

Table 26: Pinheads of black pepper samples dried under three different methods,

results of ANOVA, and critical ratio estimates of various tests

Light berries were present in all pepper samples. However, the level was reduced

in solar dried sample group. The amount of light berries in commercial samples was 2.9%,

in conventional 1.36%, and in tunnel dried 0.44% (Table 27)

Table 27: Light berries content of black pepper samples dried under three methods,

results of ANOVA and critical ratio estimate of various tests.

2.4 Discussion

In Kerala pepper is cultivated in a variety of soil types ranging from sandy soils of

coastal areas, black muddy soils of barren lands to rocky terrain high-elevated regions of

the State. According to the farmers pepper can be cultivated in any soil, provided there is

enough drainage. The Kerala Agricultural University recommends soils rich in organic

matter with proper drainage for pepper cultivation (Rajamohanan, 1996). Pillai (2000) says

that pepper can be grown in coastal areas effectively than in other fertile regions,

especially in the context of low productive conventional system. Though the plant grows in

every soil, it is better to select an ideal soil of enough sand and earth rich in organic

matter (Anonymous. 1998a). According to Paulose (1973) pepper is grown in lndia on a

variety of soils such as red loams, sandy loams, clay loams and red laterite soils; but the

best plantations are on the humus rich virgin soils of the hill slopes of the Western Ghats.

Observations of the present study have shown that soil of pepper cultivated areas in

Kerala posses good drainage

Planting standards used are more or less same in every part of the State. Method

of planting and planting materials used are also similar. According to some farmers trees

with huge trunk and rough skin used as standards not only enhances yield, but also

increase the disease resistance capacity of the vines. Healthy growth of the vines and

subsequent sustained production of pepper using concrete piles and teak logs as

standards are also reported (Sudha and Meerabhai, 2001; Prasad, 2001). Senile rubber

plants are also considered to be good for better growth (Nelliany, 1999). Survey revealed

that Karimpanas (Bomssus flabellifer) of Palakkad district give good yield when used as

planting standards. These standards are predominant in this area and are ecologically

suitable also. The present investigation revealed that about 41 cultivars of pepper are

cultivated in Kerala. Panniyur 1 and Karimunda are the most s~ught-after varieties among

the farmers. The chances are also for these cultivars to dominate in the coming years.

These observations agree with the findings of Farm Information Bureau of Kerala as well

(Gangadharan, 1998aj. Pradeepkumar et a/. (2001) opined that there are about 100

varieties of pepper under cultivation in India. Comparing the different districts, ldukki,

53

Kannur and Wayanad have the highest diversity of cultivars. In the same plantation a

variety of cultivars are grown together. This is one of the reasons why the samples

collected in this investigation consisted of an assortment of berries.

In Kerala pepper is grown as monocrop as well as mixed crop. Large-scale

cultivation Of pepper as monocrop is done only on hill slopes by clearing the forest areas.

Piuthi (1993) reported 3 systems of cultivation viz. monocropping, mixed cropping, and

companion cropping. High variation in spacing method was noticed during survey. It is

revealed that a minimum of 2 meter distance is necessary between standards and rows.

However except for pure gardens farmers do not follow such kind of measurements.

Usually farmers start planting of pepper during the onset of southwest monsoon.

Planting materials used are similar in most places, either rooted nursery cuttings or

cuttings from healthy mother plants. Recently a process called rapid multiplication

technique (Jabbar and John, 1999) has been established widely among the farmers. By

this method the Central State farm (Government of India). Aralam, Kannur produce

thousands of nursery poly bags every year.

Field observations showed a variety of practices in plant protection and manuring

methods throughout Kerala. Instead of adopting practices suggested by nodal agencies

such as Agricultural University and Spices Board, farmers tend to develop their own

methodologies for manuring and protection processes. Some farmers are also engaged in

organic farming. The trend of organic cultivation is a promising method for sustainable

pepper production. The survey indicates that, farm preparation of composts,

vermicomposts and organic pesticides like neem, tobacco decoction and other traditional

manures and medicines are not uncommon in various parts of Kerala. Application of

Trichodema spp. Pseudornonas spp. larvae of Chtysoperia camea, Bacillus thuringenisis,

Nuclear Polyhedrosis Virus (NPV), VAM fungi etc. linked biological control measures have

started recently (Sujatha and Pillai, 1998; Sarma and Peter, 1999). A few farmers have

started to produce 'pandecompost', a new organic fertilizer developed by Tamil Nadu

Agricultural University, Coimbatore. However majority of the farmers are still depending

54 --

upon dried wwdung as the chief fertilizer and bordeaux mixture as the most effective

fungicide.

Regional variations are noticed in the plant protection methods especially during

the initial stages of development. The young plants are often shaded with palm fronds.

Some farmers do mulching at the base, cover the basal open portion of the standard with

hanging branches, and tied with the standard. According to Sujatha and Pillai (1998) it is

very common in Kannur and Kasaragod regions that the soil temperature raises up to

60°C during summer. They suggested that proper mulching of the base and covering of

the pepper plants should be done during these hot seasons. The farmers believe that

these type of field operations will enhance the production and, maintain a tuft of healthy

plants at the base. Protection of collar area (region where stem and root joins) prevents

the attack of soil borne fungus.

Present survey revealed the occurrence of quick wilt disease all over the State,

irrespective of regions, cultivars and cultural practices. Some of the farmers have

succeeded to wipe out quick wilt disease by adopting some unique methods, which are

formulated based on their experiences. It was observed that a farmer in Peerumed Taluk

of ldukki district has selected a disease resistant variety of pepper. Certain others have

reduced disease infestation by providing hygienic premises to the plant. However quick

wilt disease still remains the chief bottleneck in pepper cultivation. The intensity of quick

wilt is more in ldukki and Wayanad districts. In addition to the extensive area of cultivation,

the high humidity and precipitation in these high ranges may be contributory factor to this.

It is observed that some of the pepper plants grown in sandy soils of Alappuzha

district donot show any incidence of diseases for a significant period. Degree of success

of pepper cultivation depends upon friable soil structure, adequate water holding capacity,

good drainage, and good organic nutrient reserves (John eta/., 1999).

Rainfall is the chief factor that influence flowering of pepper. June - August is the

flowering period. John et a/. (1999) have the opinion that rains from May - June in a

season influence the pattern of flowering ideally. Flowering pattern may differ according to

the geographical distribution of pepper plantations (Thajudheen, 1981). Present study

underlines this observation regarding the pepper flowering.

Except for a few wild varieties, the harvesting season of black pepper in Kerala

falls during November to April. Krishnamurthy (1969) has said that there are usually two

crops in lndia, one in August-September and the other in March-April. Survey

observations revealed that flowering and climatic patterns may alter the harvesting season

to some extent.

It has been reported that the major constraint for pepper production in lndia is the

low productivity. Pruthi (1993) said that the present average yield of pepper is about 250

kglha in lndia. Survey observations showed that production of pepper from a single plant

is comparatively high. Pradeepkumar et a/. (1999) have conducted experiments on the

yielding behavior of Panniyur I and witnessed high yield per plant. An yield of 10 kg per

plant is not rare in Kerala. Since majority of the plantations are mixed andlor companion

type, the number of plants in a hectare might be very low in comparison with similar data

of other countries, where pepper is cultivated as a monocrop. Madan et a/. (2000) studied

the economics of pepper cultivation in lndia and have agreed that the reason for low

productivity is mainly the cropping differences. Adoption of improved agro-techniques has

a major role in high production in Malaysia and Indonesia (Mathen, 1999). Another study

suggests that the reason for low productivity in lndia is due to various diseases

(Muthukulam, 2000).

Survey findings underline the mishandling and unhygienic post-harvest practices

prevailing in Kerala. Very few farmers carry out scientific mode of post-harvest treatments.

Majority of the farmers have adopted the practice of detaching the berries before drying.

In Indonesia, the berries are usually left attached to the spikes for the first few days of sun

drying (Purseglove eta/., 1988). Though many of the farmers are well aware of the quality

improvement after blanching, they are still hesitant to do it. According to them, all these

processes of course improve quality; but will not enhance the price of the commodity.

Blanching is a common practice in competing countries. However in Kerala some farmers

soak the berries in boiling water for, more than five minutes. Lewis et a/. (1976) advised

56

that prolonged blanching should be avoided since this can deactivate the enzymes

responsible for the browning reaction. Cleaning of pepper before and after drying is not a

regular process since it adds labour input. Studies conducted by Sreekumar (2001)

showed that conventional method of pre-treatments in Kerala are unhygienic and

unscientific.

Black pepper is traditionally dried on floors smeared with cowdung or on bamboo

mats, due to which the dried product gets contaminated with mammalian excreta like

cowdung besides rodent excreta (George, 1996a). Present survey revealed that sun

drying takes 7 to 10 days for the drying of pepper. Since no scientific methods are

available to detect the completion of drying, the final moisture content will be always in a

range between 8 and 22 percent (Sivadasan, 1996a).

In general spice recovery of pepper ranged between 33-37 percent. However field

observations revealed that some varieties may give 40% or more. This could be due to

incomplete drying as well. Krishnamurthy (1969) reported that the spice recovery of black

pepper is about 33% only. Panniyur 2 has a recovery percentage of 35.7 (Kumar eta/.,

1997).

Cleaning of dried pepper is rarely done in the plantations of Kerala, as it reduces

weight. Dried product is directly brought to the market as ungarbled pepper. According to

Purseglove et a/. (1988), in India, Indonesia and Sarawak, pepper production is

predominantly a small holders' crop and the final cleaning, grading and bagging of the

dried spice is carried out by exporting firms. However the survey identified that a

considerable percentage of farmers always do a partial cleaning process called

winnowing.

Very often small holding pepper producers are forced to dispose their produce

immediately after the harvest, sometimes even before harvest (Pruthi, 1993). Findings of

this survey also agree to this. Large-scale producers with storage facilities alone keep

their produce under storage. Due to the lack of these facilities, and the immediate need of

money the small-scale farmer is forced to sell the produce at the existing price. A number

of different materials are used for packaging in Kerala. Present study revealed that

-- 57

farmers are still not aware of the scientific storage methods. Storage is one of the

important functions in orderly marketing of black pepper. Some farmers strongly hesitate

to use polythene materials for packaging. However it is clear that the factor that influences

storage life is the final moisture content of dried pepper. Survey results underline the

importance of post-harvest methodologies to be adopted for the quality improvement of

pepper.

The mean initial moisture content of pepper barriers collected from 34 stations

was 70.4%. Samples from Pulpally had the highest moisture content (72.4%), and that of

Kalady had the lowest (68.6%). Kama~ddin et a/. (1994) worked out the initial moisture

content of pepper and reported a maximum of 72.3% (wet basis). According to Kachru

and Gupta (1993), harvested pepper contains about 70% moisture content. Spices Board

(Government of India) (Anonymous, 2000c) reported that green pepper contains 7585%

moisture. Reasons for this variation may be the maturity at harvest, cultivar variety,

analytical errors etc.

Various pepper samples dried in solar tunnel dryer took about 10 hours for

optimum drying, however drying by commercial and conventional methods took 39 and 31

hours respectively. This reduction in drying time would have been due to the higher

temperature attained inside the dryer, the low relative humidity, and the one fruit thickness

of the spread layer. Esper and Muhlbauer (1996) have established a decrease in drying

time for most of the agricultural products using solar tunnel dryer. Zacharia (2000)

suggests solar tunnel dryer as the best equipment for the effective drying and quality

retention for black pepper. Studies have shown that compared to the temperature the

influence of the relative humidity and velocity of the drying air are of minor importance for

the drying time reduction (Bala and Mondol, 2001). Sigge et a/. (1998) have explained that

the drying rate generally increased with increasing temperature and decreased with

increasing relative humidity. The present study agrees with this explanation. The results

also show that the time taken for open sun drying could be reduced slightly by proper

care.

In the present investigation spice recovery after drying in solar tunnel dryer was

low when compared to commercial and conventional drying. However final moisture

content was high in commercial (15.7%) and conventional (14.2%) samples. Solar tunnel

dried samples showed only 10.75% final moisture content, which is very near to the

required quality standards. The spice recovery in solar tunnel dryer was low due to this

low moisture content. The standard level of moisture content (maximum) specified by

USFDA (United States Food and Drugs Administration) and ESA (European Spice

Association) for dried pepper is 11%. According to George (1996a) farmers dry pepper

only to a moisture level of 16-18%. Pruthi (1993) has the opinion that conventional method

of drying will create a product of more than 15% moisture. Rain, low sunlight,

remoistening during night and humid days may affect drying property. Bala and Mandol

(2001) has experimentally proved that the fast and safe reduction of moisture content

level improves the quality under solar tunnel drying. In the present investigation the final

moisture content could only be reduced by 14% by open sun drying. So only solar tunnel

drying can reduce the moisture content to the prescribed standard. Kandiannan (2000)

reported that the percentage recovery of dried pepper from green berries varies from 27%

to 34% depending upon the maturity of berries at harvest. The percentage recovery

attained in this investigation is from 34-38%. Purseglove etal. (1988) opined that the yield

of black pepper is around 36kg from 100kg of the fresh berriei. Ravindran and Nair (1984)

have suggested that depending upon the cultivar variation changes in the percentage

recovery occur. The pepper samples collected for this study were from different sampling

stations and assorted in nature. According to Sumathikkutty et a/. (1989) pepper of

commerce is a mixture of many cultivars.

Observations of the present study showed that commercial and conventional

samples were not dried properly since they contain high amount of moisture. Farmers

believe that weight reduction occurs when pepper is dried using advanced methods

(James and Regina, 1992). Increase in moisture content might be enhancing the weight of

the commodity, and fetch more money. However pepper with high moisture content

increases the chances for attack by microorganisms.

P ~ t h i (1980) illustrated some mechanical methods for the drying of pepper, which

can be used in adverse conditions. Annamalai et a/. (1984) have developed a kiln dryer

for pepper drying. Both these methods are high-energy consuming processes, and are

expensive. Freeze-drying is also a costly dehydration process, but currently well

established (Raghavan and Shankaranarayana, 1992).

The minimum standard value of volatile oil is 2% as suggested by USFDA (United

States Food and Drugs Administration) and IS0 (International Organization for

standardization). In the experiments conducted, the solar tunnel dried and conventional

samples attained this level of volatile oil. The commercial samples had significantly low

volatile oil content. The results clearly show that open sun drying as well as solar tunnel

dryer can give similar results with respect to volatile oil retention. But why, the farmers are

not able to attain it is a matter of concern.

It is known that delayed and extended drying will reduce the volatile oil in terms of

quality and quantity (Govindarajan, 1976). Another important reason for the loss of volatile

oil during conventional drying is over-blanching. According to Jacob et al. (1985) many

farmers dry pepper after blanching for more than 5 minutes, a possible reason for the

reduction in the oil content. It is suggested that blanching also helps to keep maximum

volatile oil quality (Mammootti, 1999). But this must be restricted to one minute only.

According to Jacob eta/. (1985) prior to drying a baptism of green berries in 80-82°C hot

water helps to avoid loss of oil, beyond that temperature quality deterioration may result.

According to Larcher (1967) the technique of keeping freshly harvested peppercorns for

24 hours in the shade is the best treatment for the highest yield of essential oil. Also,

many enzymatic and microbial reactions may have considerable influence on the volatile

oil quality especially in conventional processing (Purseglove et a/., 1988). According to

Natarajan and Shankaracharya (1974) the drying temperature is critical with spices and

temperature beyond 50-60°C in mechanical dryers is detrimental to the product because

there would be loss of volatile oil. But in the present investigation neither the prolonged

drying period (31 hour in conventional drying) nor the higher temperature (30-70°C inside

the tunnel dryer) seemed to affect the oil content. So probably, the blanching technique

would have helped to retain the volatile oil at >2% in the conventional and solar tunnel

dried samples. Traditionally, the farmers either do not do blanching or if they do, it is done

by soaking in boiling water for a few minutes. In this experiment the blanching method

used was to dip in near boiling water for exactly one minute. May be this blanching

method is the critical factor that retains the volatile oil content.

In the international market oleoresin of black pepper is the most desired value

added extract from pepper. Minimum oleoresin percentage as per the USFDA standard is

7.5% by weight. In the present investigation only the solar tunnel dried samples could

qualify this standard value; open sun dried samples had slightly lower oleoresin content.

Like volatile oil, open prolonged sun drying method might be the reason for the decrease

in oleoresin content among commercial and conventional samples as suggested by

Purseglove et a/. (1988) and Govindarajan (1976). Improper drying, microbial spoilage,

and extended blanching also have profound influence on oleoresin retention. Without

proper pre-treatments it is very difficult to produce pepper of maximum oleoresin content.

Since oleoresin is a non-volatile compound high temperature does not affect

oleoresin generally. The blanching improves retention of oleoresin (Jose et a/.. 2001).

According to Lewis eta/. (1 976) the oleoresin yields depend on the solvent employed and

the type and quality of the spice material used.

The standard value of piperine content (minimum) is 3.5 as recommended by

USFDA (United States Food and Drugs Administration). In the present investigation all

pepper samples had higher piperine content than the minimum specified. The highest

piperine content was for solar tunnel dried samples. Unscientific processing and

mishandling of pepper can result in loss of piperine (Govindarajan, 1976). Piperine is very

much sensitive to light; extended exposure to sunlight may change its chemical structure,

and lead to subsequent quality deterioration (Pruthi, 1999). Larcher (1967) suggests a

pre-treatment of heaping spikes for about 24 hours for maximum retention of piperine.

The overall picture that emerges from the physical quality analyses of black

pepper dried under commercial, conventional and solar tunnel drying methods unveils that

the first two methods create unhygienic dried products. But solar tunnel dried pepper is

completely devoid of any of the physical contaminants. Studies conducted by Spices

Board (Anonymous, 2000c), regarding the factors influencing reduction in pepper quality

ascertained that contaminants like pests, fungi, microorganisms, foreign matter,

poisonous substances or impurities get into the commodity from the materials used for

processing. Microbes and dirt are also introduced into the product through unhygienic

habits of the people who handle the produce during post-harvest operations.

Number of dead insects was rather high in commercial samples. Out of the 34

samples studied 82% of commercial and 68% of conventional samples contained dead

insects. The maximum number of dead insects (16 by count) was observed from a

commercial sample. Solar tunnel dried samples secured high quality over conventional

and commercial samples with respect to the number of dead insects. Since ASTA

standard is 2 (by count, maximum) commercial samples are considered as highly

contaminated.

Black pepper is highly prone to the attack of insects especially during storage. A

survey conducted by Spices Board revealed that many of the samples screened by them

contained insects at a peak rate than the standard (Sivadasan, 1996a). The increase in

the number of dead insects in commercial and conventional samples may be due to the

uncontrolled as well as unprotected drying. Insects cannot attack the dried berries if

properly dried up to a moisture level below 11% (Kumar and Anandaswamy, 1974). One

reason for the attraction of insects to pepper during the drying process is aroma (Muthu

and Majumdar, 1974). Open spreading of the berries and drying without any timely

monitoring may also result in the attack of insects.

Since solar tunnel dryer is completely protected until the completion of drying, and

the desired final moisture content is achieved, dryer is safe from insects (Muhlbauer,

1986). Solar tunnel dried pepper has a glossy and hard nature. This leads to the spread of

an odour of volatile oil to the surrounding air. Being a high antimicrobial agent black

pepper oil can resist the attack of insects also (Sherman and Billing, 1999). Bala e l a/.

(1999) have experimentally tested to produce commodities free of insects using solar

tunnel dryer. Deviation from proper drying and maintenance of desired final moisture

content are the chief factors influencing insect attack.

The present data on mammalian excreta showed that only solar tunnel drying

achieved the desired quality. Samples dried under this method do not contain mammalian

excreta; whereas 65% commercial samples and 41% conventional samples were

contaminated with excreta. In comparison with ASTA standards i.e. 1 mgllb (maximum

permitted) solar tunnel dryer samples maintains good quality over the other two.

According to Sivadasan (1996a) the excreta contamination is because of our age-

old practice of using cowdung for smearing over bamboo mats and other surfaces for

pepper drying. Even now in Kerala many of the farmers are adopting such methods for

drying. Besides this, the most important cause for this contamination is open sun drying.

There has been instances in 1987-88 period when Indian exports of pepper to USA was

subjected to Automatic Detention because of the presence of excreta of mammals and

mold in majority of consignments (Anonymous, 2000~).

In the present investigation threshing and drying were conducted hygienically, so

that the chances of excreta incidence was low. The berries were spread in plastic net kept

inside the tunnel. If any traces of excreta are present by mere chance it will filter out

through the holes of the net (Joy and Jose, 1998b). Because of protected drying

probability of entry of rats and other animals was nil. Obviously, solar tunnel drying

method keeps away mammalian and other excreta during any of the post-harvest

operations of black pepper.

The presence of other excreta such as excreta of birds and insects are also

objectionable. However no significant incidence was observed in any of the three samples

groups. Sivadasan (1996a) have the opinion that the contamination with rodent and other

excreta do not take place at the growers level.

Moldy berries are very much prevalent in commercial samples; incidence was

100%. However conventional samples showed only 24% of incidence. Mold growth was

completely absent in solar tunnel dried samples. Mean data of commercial and

conventional samples observed were 7.1% by weight and 0.9 by weight respectively.

Maximum of 1% by weight of mold is the tolerance limit of ASTA and in solar

tunnel dried samples the mold content was nil. The appearance of mold has a linear

relationship with its final moisture content. Commercial samples that contained highest

mold percentage was not dried properly, its final moisture content was 13.1%. The solar

tunnel dried samples were dried up to a moisture level of 10.75% mold formation was

absent.

Patil (1989) says that mold formation is very common in conventional processing.

The first stage of drying is most important. If the commodity is not properly dried during

this stage the permeability of the outer covering will be lost and it checks further

evaporation. Joy etal. (1999) supported this view. Even though the product appears to be

dried the internal moisture may not be released (Davis, 1996). A possible chance for the

establishment of aflatoxins is also unavoidable if one cannot control mold growth during

processing (Sivadasan, 1996a). However solar dryers are promising. Studies conducted

by Ratti and Mujumdar (1997) have estimated that formation of mold during conventional

processing can be overcome by the use of efficient solar dryers. In the opinion of

Raghavan and Shankaranarayana (1992) improper drying of pepper results in a

graylwhite patch (mold growth) on the surface. The incidence of aflatoxin in pepper can be

reduced up to a limit if proper drying measures are being adopted. The aflatoxin forming

fungus (Aspergillus flavus) will be destroyed at a temperature above 50°C. From the

present study it is revealed that solar drying enhances hygienic nature of pepper.

As per the ASTAJUSFDA standards the maximum limit of insect defiledlinfested

berries is 1% by weight. Solar tunnel dried samples alone achieved this level in this

investigation. Almost 100% occurrence was seen in the commercial and conventional

samples. The presence of insect defiledlinfected berries is of common occurrence in the

traditional farms of Kerala (Govindarajan, 1976). According to Sivadasan (1996a) the

incidence of insect defiledlinfected is mainly due to the attack of pollu beetle (Longitarsus

nigripensis) during the early stages of the crop growth. If the attack of the above pest has

happened before drying then all the samples dried under three methods should have had

a similar rate of attack. But the results of this investigation lead to the assumption that

insect attacks have happened during drying as well. It could be also that some of the

berries, which were infested before drying, might have been removed during cleaning or

sieving, in the case of solar tunnel drying method.

Jayaraman et a/. (1992) studied the solar drying of different agricultural crops and

suggested that in addition to solar drying proper pre and post handlings should be

adopted for achieving this quality. Studies conducted by Jose et a/. (2001) disclosed, that it

is possible to produce pepper without the incidence of insect defiledlinfested berries by

adopting solar tunnel drying method.

The incidence of extraneous matter was 100% in commercial as well as in

conventional sample groups. Commercial samples had the highest quantity i.e. 2.9% by

weight; where as that of solar tunnel dried set was 0.5% by weight. ASTA tolerance limit is

1% by weight (maximum). Agmark range is 0.5% (for MGI-Malabar Garbled) to 7% (for

UGL-Ungarbled Light Black pepper). In the present study solar tunnel dried as well as

conventional dried group succeeded the quality standard in terms of extraneouslforeign

matter. Present investigation illustrates that traditional methods of drying by the farmer

facilitate the chances for the contamination of pepper with extraneous matter. Major

extraneous matter found in the samples are stones, pinheads, plant parts, pulses, dusts,

soil etc. According to Sivadasan (1996a) the presence of stone is mainly due to the

conventional method of drying black pepper on the ground. However Govindarajan (1976)

reports, that the contamination due to extraneous/foreign matter is because of many

factors viz. threshing in unhygienic floor by trampling, spreading on ugly surfaces, open

drying, and heaping in unscientific manner after drying. Farmers are not conducting any

washing or cleaning operations before drying. Many of the unwanted foreign particles

would enter during the harvesting time especially during humid morning hours. Dust and

dirt from the atmosphere and ground would adhere on the berries aided by moisture and

humidity. Velappan et a/. (1993) have suggested that unless hygienic handling practices

are adopted during the post-harvest processing pepper would be contaminated with

extraneous matter. This generally happens at the growers' level and also at the exporters'

level.

Drying in solar tunnel dryer minimizes contamination by foreign matter. Tunnel

area of the dryer is built with a provision for sieving (Esper and Muhlbauer, 1996).

Therefore no particles less than 2 mm is retained with pepper after drying. Blanching too

facilitate cleaning (John, 2000).

Pneumatic separators equipped with magnetic separators are used to remove

debris, based on the relative specific gravity of particles such as dirt, grit, stones, stalks,

leaves etc. (Pruthi, 1993). Dried berries are generally cleaned manually by winnowing or

by using blowers. But these processes are done in large farms and trading centres only.

Marivala (1974) describes many of the garbling and cleaning units and their functions,

used in exporting industries. Wahab (1995) fabricated a rotary type black pepper cleaner

for this purpose. Present investigation concludes that the production of black pepper of

high quality in terms of extraneouslforeign matter can be done through solar tunnel drying.

It is also confirmed that pre-drying treatments have definitely a major role to get a product

devoid of extraneouslforeign matter. Proper drying will not detach skin of the berries

during drying, to form the extraneouslforeign matter.

Pinheads are immature berries of pepper seen along with black pepper. Even

though pinheads are exported in some grade names, presence of pinheads in whole

pepper category is considered as unwanted matter or adulterants. Present study

estimated an incidence of 82% in commercial and 56% in conventional sample groups.

However only 29% of incidence has occurred in solar tunnel dried samples. A maximum

pinhead quantity of 4.9% by weight was obtained from a sample dried under commercial

method. However among the solar dried samples maximum amount obtained was only

0.2% by weight. No standard value is specified for pinheads in general. However a

maximum of zero (for GL-Grade Special) to 15% by weight (GL-Grade 3) is the Agmark

standard. ASTA quality specification considers pinheads as extraneous matter. The mean

data of the three sample groups indicated that solar tunnel dried pepper performed

outstanding quality in this respect.

The presence of pinheads can be reduced to a certain extend by conventional

practice of winnowing. However standard quality is not usually achieved (Wahab, 1995).

According to Sivadasan (1996a) the presence of pinheads in large amount will definitely

lead the exporters come to the conclusion that the pinheads are purposefully added as an

adulterant. Farmers do not follow any cleaning practices before and after drying. Others

consider it as a part of the pepper produce. Pruthi (1993) says that processing of pepper

is generally done either by the traders or exporters. Primary processing that has been

done by the farmers does not achieve good quality in terms of pinheads and light berries.

Chances of pinhead occurrence are low in solar turlnel dryer, since processing

involves cleaning and sieving before drying (Joy et a/., 2002). Joy and Jose (1998b) have

reported that most of the pinheads are lost during blanching and washing.

Recommendation of Spices Board (Government of India) too insists on these pre-

treatments for the production of pinhead free pepper.

The presence of light berries was rather complete in every sample group. The

highest measure of 8.2% by weight was obtained from a commercial sample. In

conventional samples the highest was 2.8% by weight. An average amount of 0.5% by

weight was found in solar tunnel dried samples. Agmark specification for light berries is in

a range of 2% by weight (for MGI-Malabar Garbled) to 20% by weight ((MUG Grade 4,

Ungarbled Malabar) depending upon the grade. This study revealed that the most

superior quality is achieved by solar tunnel drying. Wahab (1995) studied the disinterest in

removing light berries by traditional farmers since it is time consuming and labour

intensive. Perhaps light berries having similar size as that of whole pepper; will not be

removed completely in traditional sieving. However in solar tunnel drying due to high

temperature light berries shrink to small size, or will disintegrate to form foreign matter.

Blanching and washing too have the power of accelerating the removal of light berries.

Results of the solar tunnel drying of black pepper conducted by Jose et a/. (2001) also

delivers such a high quality product without any light berries.

Data on the drying experiments and various quality ;arameters conducted during

the second season also confirm the above observations. Statistical analyses clearly

revealed that the investigations of both the seasons have no significant difference in the

results and underlines the reproducibility of results.

The results of the drying experiments clearly illustrate that for pepper solar tunnel

drying is superior to open sun drying as it reduces the optimum drying period,

considerably improves the physical quality of the product, and retains the chemical

ingredients of interest within the acceptable limits of export quality. The study has also

shown that sound pre-drying treatments and clean practices can improve the quality of

traditional open sun dried pepper to a certain extent.