Upload
trinhdien
View
217
Download
0
Embed Size (px)
Citation preview
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.