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The main objective of this research was to characterize High Quality Cassava Flour (HQCF) produced from local and improved cassava varieties. Fresh raw cassava tubers of local and improved varieties were collected from Lusaka (Chongwe) and Luapula (Mansa). Cyanide content and moisture content was determined on the raw cassava tubers. HQCF was produced from all the raw cassava tubers by peeling, washing, chipping, drying and milling. The proximate composition, amylose content, and cyanide content were determined on the HQCF that was produced. The collected improved cassava varieties from Luapula were identified as: Bangweulu, Chila, Kariba, Kampolombo, Nalumino, Mweru, Kapumba, and Tanganyika; and the two local cassava varieties were Katobamputa and Namunyongo. The local varieties collected from Chongwe included: Kamuliboko, Linangwa, Lipalumusi, Nakamoya and an improved variety (Nalumino). It was found that the cyanide content for the raw cassava ranged from 82.39-8.75mg/kg with a mean of 29.26±30.15 mg/kg. Namunyongo had the highest while Nalumino had the lowest cyanide content. The mean moisture content for the raw cassava varieties was found to be 61.09±1.17% which was closer to the literature value of 62% reported by Onwueme (1983). The proximate composition of HQCF was found to be: mean ash content for the local varieties was 1.95±0.32% while improved was 2.03±0.69% but no significant differences (P>0.05) were observed; mean protein content for the local varieties was 1.07±0.42% while improved was 1.41±1.01% with no significant difference (P > 0.05); mean fat content for the local varieties was 0.38±0.41% while improved was 0.61±0.4% and did not differ significantly (P > 0.05); mean moisture content for all the varieties was 6.48±1.61%. The mean ash content for the local varieties from the two locations differed significantly (P 0.05). The mean amylose content for the local varieties was 17.89±1.56% while improved was 16.49±1.1% and a significant difference was observed (P
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THE UNIVERSITY OF ZAMBIA
SCHOOL OF AGRICULTURAL SCIENCES
FOOD SCIENCE AND TECHNOLOGY DEPARTMENT
CHARACTERISATION OF CASSAVA VARIETIES FOR APPROPRIATE
UTILISATION
FINAL YEAR RESEARCH PROJECT
LIYALI LIBONDA
18TH JUNE, 2012
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ABSTRACT
The main objective of this research was to characterize High Quality Cassava Flour (HQCF)
produced from local and improved cassava varieties. Fresh raw cassava tubers of local and
improved varieties were collected from Lusaka (Chongwe) and Luapula (Mansa). Cyanide
content and moisture content was determined on the raw cassava tubers. HQCF was
produced from all the raw cassava tubers by peeling, washing, chipping, drying and milling.
The proximate composition, amylose content, and cyanide content were determined on the
HQCF that was produced. The collected improved cassava varieties from Luapula were
identified as: Bangweulu, Chila, Kariba, Kampolombo, Nalumino, Mweru, Kapumba, and
Tanganyika; and the two local cassava varieties were Katobamputa and Namunyongo. The
local varieties collected from Chongwe included: Kamuliboko, Linangwa, Lipalumusi,
Nakamoya and an improved variety (Nalumino). It was found that the cyanide content for the
raw cassava ranged from 82.39-8.75mg/kg with a mean of 29.2630.15 mg/kg.
Namunyongo had the highest while Nalumino had the lowest cyanide content. The mean
moisture content for the raw cassava varieties was found to be 61.091.17% which was
closer to the literature value of 62% reported by Onwueme (1983). The proximate
composition of HQCF was found to be: mean ash content for the local varieties was
1.950.32% while improved was 2.030.69% but no significant differences (P>0.05) were
observed; mean protein content for the local varieties was 1.070.42% while improved was
1.411.01% with no significant difference (P > 0.05); mean fat content for the local varieties
was 0.380.41% while improved was 0.610.4% and did not differ significantly (P > 0.05);
mean moisture content for all the varieties was 6.481.61%. The mean ash content for the
local varieties from the two locations differed significantly (P < 0.05) while fat and protein
content did not show any significant difference (P > 0.05). The mean amylose content for the
local varieties was 17.891.56% while improved was 16.491.1% and a significant
difference was observed (P
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LIST OF ABBREVIATIONS
ACU Acceleration of Cassava Utilization
ANOVA Analysis of Variance
AOAC Association of Official Analytical Chemists
CSO Central Statistical Office
FAO Food and Agriculture Organization
FoDiS Food Crop Diversification Support Project
HQCF High Quality Cassava Flour
PAM Programme Against Malnutrition
UNZA University of Zambia
WHO World Health Organization
ZARI Zambia Agriculture Research Institute
ZRTIP Zambia Root and Tuber Improvement Programme
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CHAPTER 1
1.0. INTRODUCTION
Cassava is a plant whose centre of origin is in South America. It is classified scientifically as
belonging to the family Euphorbiaceae. Manihot esculenta Crantz comprises the two
varieties of cassava, the bitter variety classified as Manihot esculenta and the sweet variety
as Manihot dulcis (Encarta, 2009). It is known under various names depending on where it is
cultivated; in Brazil, it is known as Mandioc, Yucca in other parts of South America while in
Zambia it is known as Kalundwe in one of the local languages. It is a perennial with
conspicuous, almost palmate fan shaped leaves which are more deeply parted into five to
nine lobes. Both its leaves and starchy roots are consumed in Zambia. The starchy roots are
clustered around the base of the plant and extend about 60cm on all sides. A single starchy
root, under favourable conditions, and depending on the cultivar, may weigh as much as four
kilograms (Kamoteng, 2005).
The principle classification of cassava as being bitter or sweet is based on taste which is
determined by the amount of cyanogens present in cassava. There are two types of
cyanogens present in cassava: the cyanogenic glycoside which comprises linamarin and
lotaustralin and the non-glycoside which comprises cyanohydride and hydrogen cyanide.
The glycosides are considered bound and found in the vacuoles of the cassava cell while the
non-glycosides are considered free; hence they easily diffuse in water. For linamarin, the
endogenous enzyme linamarase is needed to set the cyanide free.
In Zambia, cassava is grown predominantly in four provinces. These are Luapula, Northern,
North-western and Western province. The leading producers have been Luapula and
Northern provinces which contribute about 70 % to national production as of 2009. Western
province is second with 16 % (CSO, Household Survey, 2008/09).
Cassava can be classified into two main varieties: local and improved varieties. The latter
variety has higher yields, early maturing, and is disease resistant. The Zambia and Tuber
Improvement Programme (ZRTIP) in 2000 introduced seven improved cassava varieties
namely: Bangweulu, Kapumba, Nalumino, Mweru, Chila, Tanganyika, and Kampolombo.
Apart from the improved varieties, there are a number of local varieties grown in these four
provinces (Haggblade et al, 2007).
Traditionally, cassava has been regarded as a subsistence crop for low-income families
providing high levels of carbohydrates during shortages of other crops because of its
tolerance to drought and ability to grow in poor soils. Recently, the perception of cassava as
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simply a subsistence crop has begun to change and there is growing interest in developing
its commercial potential through improved varieties, increased productivity, harvesting and
processing technologies (Haggblade et al, 2007). In order to diversify its usage, new
processing technologies have been developed. Cassava is now being processed into a
highly versatile product called High Quality Cassava Flour (HQCF) that has found usage in
many industries such as the Food industry, the Paper Manufacturing industry, Wood
industry, Textile industry, Feed companies, etc.
High Quality Cassava Flour (HQCF) is non-fermented Cassava flour that is produced by
using a chipper and/or a grater. This technology solves the problem of discolouration that is
quite prominent in fermented flour, reduces the level of cyanide and also reduces the
number of days required to produce cassava flour.
1.1. PROBLEM STATEMENT
Cassava production in Zambia has increased over the years. According to a statistical report
published by Food and Agriculture Organization (FAO) in 2005, cassava production
competes favourably with maize. However, its value chain has not yet fully developed when
compared to maize (Chitundu et al, 2007). There is insufficient information on the potential
uses of each cassava variety in Zambia; this has actually restricted cassava usage to the
production of fermented flour that is being used for the preparation of a thick porridge called
nshima. In some cases, it is either consumed by boiling fresh tubers or roasting dried chips.
This under usage of cassava has been attributed to a lack in knowledge of the suitability of
each variety for use, as the cyanide content, the functional characteristics, and the proximate
composition differs among the varieties (Tran et al, 2007).
Cassava is bulky and highly perishable. Hence, to overcome these limitations requires
appropriate strategies and technology for post-harvest processing and utilization (Dufour et
al., 2002).
Understanding the characteristics of HQCF from each cassava variety will provide empirical
data which can be used to stratify and pinpoint appropriate usage for each cassava variety,
come up with better processing methods to ensure low levels of cyanide and hence, diversify
its usage.
There have been deficiencies in the traditional preparation of fermented cassava flour in
that; the process is quite unhygienic; spreading the product on the ground makes it
vulnerable to contamination, for example, extraneous material or dust particles and also the
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process of drying in flour production can be difficult particularly during the rainy season when
the product can become mouldy and lose quality. Hence, the production of HQCF which
eliminates these deficiencies needs to be promoted.
1.2. MAIN OBJECTIVE
To characterize High Quality Cassava Flour produced from local and improved Cassava
varieties.
1.2.1. SPECIFIC OBJECTIVE
To carry out a survey on the types of local and improved cassava varieties
available in Zambia.
To determine the proximate composition, amylose and cyanide content of HQCF
produced from some local and improved cassava varieties.
To compare the physico-chemical composition of HQCF produced from local and
improved cassava varieties.
1.3. HYPOTHESIS
1.3.1. Null hypothesis; there is no considerable difference in the quality, quantity and
characteristics of the flour derived from different cassava varieties.
1.3.2. Alternative hypothesis; there are considerable differences in the quality, quantity and
characteristics of the flour derived from different cassava varieties.
1.4. RATIONALE
Cassava is a major staple food in most rural households in northern Zambia (Luhila, 2000).
Subsistence farmers have for a long time appreciated cassava advantages; it is able to
produce more carbohydrates per unit area compared to maize and other carbohydrate
sources (Luhila, 2000). However, once cassava is harvested, it deteriorates quickly, so it
must be processed or consumed soon after harvest. Cassava contains toxins called
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glycosides that need to be removed during processing as they can cause an increased
iodine deficiency, malnutrition and cause paralysis in the lower limbs (Luhila, 2000).
Efforts have been made in the past to develop new cassava varieties with high yields,
disease resistant and early maturing. These varieties include: Bangweulu, Mweru,
Kampolombo, Kariba, Tanganyika, Kapumba, Chila and Nalumino, however, the same
cannot be said in the area of utilization. In actual fact, there has not been any information
regarding the quality of cassava flour produced from each variety (Chitundu, 2009).
Traditionally processed cassava is not very stable; it can only keep for three months as it is
easily attacked by weevils hence; it suffers from high post-harvest losses. In actual fact,
about 30% cassava losses have been reported (Luhila, 2000). Processing cassava into
HQCF extends the storage up to one year (Chitundu, 2009).
HQCF is bland and whiter in colour than traditionally produced cassava flour. These two
aspects are particularly important and have led to an increase in the demand for cassava
flour as an important source of starch which is widely used in many industries (Food Crop
Diversification Support Project, 2010). The industries that use HQCF include: Food industry,
Paper board industry, Wood industry and the Textile industry. Examples of products
produced from HQCF in the food industry are bakery products such as cakes, Scones,
Bread etc. Glue manufactured from HQCF has found usage in the Paper board, Wood and
Textile industry.
This study will provide information on the proximate composition, amylose content and the
impeccable qualities of cassava flour that can be exploited to diversify its use.
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CHAPTER 2
2.0. LITERATURE REVIEW
A number of studies aimed at determining the versatility of cassava as well as its utilization
have been done. For example, processing methods have been designed to process
cassava into a high grade product called High Quality Cassava Flour (HQCF) which has a
number of advantages over the traditional cassava flour. The HQCF has found use in many
industries owing to its high quality (Food Crop Diversification Support Project, 2010). Some
studies that have been done on cassava which are particularly pertinent to this study
include: the general composition of cassava, the functional characteristics of cassava flour,
quality of wheat-cassava composite products, influence of molecular properties of cassava
starch on crystallinity and pasting properties and effects of cassava variety on the physico-
chemical properties of cassava flour.
2.1. COMPOSITION OF CASSAVA
Generally cassava comprises 62 % moisture on a wet basis and on a dry basis it is
composed of 1-2% protein, 3% fat, 31% starch, 0.83% sugar, 1-2 % dietary fibre, 0.84% ash,
2 % minerals (Onwueme, 1983). These were determined by using the methods prescribed
by the Association of Official Analytical Chemists (AOAC) and the Starch was determined by
using the Dubois et al (1956).
Cassava contains cyanogens that occur as (i) cyanogenic glucosides, and (ii) cyanohydrins
and hydrogen cyanide. The cyanogens have been found to be potentially harmful to humans
at higher concentrations. These, however, are most predominant in the bitter variety while
the sweet variety has only a relatively small amount. The sweet variety contains about 20
mg of HCN per kg of fresh root while the bitter variety can contain two times higher than the
sweet variety (FAO, 2009). Processing of cassava has been known to cause a reduction in
cyanide levels. The cyanide content can be determined by the Prussic acid analysis method.
This method basically involves distilling 10-20g of crushed cassava roots that were initially
placed in a flask containing 200ml of distilled water. The distillate is titrated with 0.02 N Silver
nitrate solution. To calculate cyanide content, 1ml of silver nitrate corresponded to 1.08mg of
hydrogen cyanide (JAOAC Ch 4, pp 151). Another method that can be used is the Brimer
and Molgaard (1986) or the quant scan method.
2.2. CASSAVA PROCESSING METHODS
Cassava has been processed to provide quality products for human consumption and
industrial use and to prevent exposing consumers to unnecessary negative effects due to
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consumption of poorly processed cassava. The two methods of processing cassava to
obtain HQCF are illustrated below;
Fig 2.1: Production of HQCF (Source: Boateng, 2007)
The following are the main reasons for processing cassava;
Harvested cassava roots contain 60-70% water. Processing reduces the moisture
content and converts cassava into a more durable and stable product.
Fresh Cassava
Peeling & Washing
Grating Slicing/chipping
Pressing
Disintegration
Sifting
Drying
Milling & screening
HQCF
Peel fragments and waste water
Fibre residual
Cassava waste
liquor
Waste fibre
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Processing cassava roots reduces the level of undesirable toxins called cyanogenic
glucosides.
Processing cassava reduces post-harvest losses because cassava is perishable and
losses can be as high as 30%.
Processing improves the quality and taste of cassava products
Bulkiness of the fresh cassava is reduced making it easy to package and transport
cassava products over long distances (Chitundu, 2009).
HQCF can be used as an alternative for starch and other imported materials like wheat flour
in a number of industrial processes. HQCF can be used in the production of adhesives for
paperboard manufacture, as an extender for plywood glues, as a source of starch in textile
sizing and as raw material for the production of glucose syrups, industrial alcohol and bakery
products (Chitundu, 2009).
2.3. CASSAVA QUALITY CHARACTERISTICS
Cassava is a crop that requires processing before consumption. The root size, flavour,
texture, colour and taste are characteristics that are important to the consumer in addition to
the critical aspect of reducing the level of hydrogen cyanide in the final product.
The quality of secondary cassava products such as bread, buns, cakes, nshima or animal
feed is dependent on the quality of the primary cassava products i.e. cassava chips, grits or
flour (Food Crop Diversification Support Project, 2010).
2.4. PRODUCT SPECIFICATIONS
The Food, Feed and Textile/Paper industries have different requirements depending on
whether for example cassava is required for feed or bread production (Chitundu, 2009).
However, cassava going to industry especially the Food and Feed industries must be safe
for consumption to avoid the risk of hydrogen cyanide exposure. The safe Hydrogen
Cyanide levels according to international standards are given in table 2.1.
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Table 2.1: International Safe Hydrogen Cyanide Levels
Fresh root Dried chips
Less than 50mg/kg Harmless CODEX. 10mg/kg is
recommended.
50-100mg/kg Moderately poisonous
Plants that accumulate more than 100mg/kg are considered
lethal
Source: Linley, (2001)
Cassava varieties in Zambia have low, medium and high hydrogen cyanide levels (Sakala,
2004). While varieties with low levels can be consumed without processing, those with high
cyanide levels usually associated with bitterness must be processed before consumption.
For example Manyokola is a sweet variety while Chila is bitter and needs elaborate
processing (Sakala, 2004). An example of the hydrogen cyanide level of popular varieties is
given in Table 2.2.
Table 2.2: Hydrogen Cyanide levels of selected Raw Cassava Varieties in Zambia
Variety Kapumba Manyokola Chila Bangweulu
mg/kg 85.71 42.39 117.21 91.25
Source: Sakala, 2004
2.5. PRODUCT STANDARDS AND MARKET REQUIREMENTS
Zambia under the auspices of the Acceleration of Cassava Utilization (ACU) task force
developed quality standards for cassava chips and flour as shown in Table 2.3. These were
approved and published by the Zambia Bureau of Standards in 2008.
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Table 2.3: Quality Standards for Cassava Chips and Flour
Cassava Chips Cassava Flour
Moisture: 10- 13% maximum Moisture content: 13% maximum
Crude fibre: 2.5% maximum Crude fibre: 2% maximum
Hydrogen Cyanide: 10mg/kg Hydrogen Cyanide: 10mg/kg
pH: 5.0- 7.0 pH: 5.0- 7.0
Starch content : 60% minimum Starch content : 60% minimum
Total ash: 3% Total ash: 3%
Source: ZABS, 2008.
The uses and specifications of HQCF in different industries are shown in table 2.4.
Table 2.4: Uses of HQCF in different Industries
Industry Derived product Product Requirements
Plywood Glue High quality -finely milled
(0.25mm),white flour, low fibre, not
fermented, with high paste, viscosity
and stability
Paperboard Glue High quality similar to plywood
Textiles Glue High quality-finely milled(0.25mm)
white flour, low fibre, no odour or
taints and not fermented, with high
paste, viscosity and stability
Confectionery Sugar alcohols, sugar syrup High quality- similar to textiles, but
paste viscosity and stability not
important
Industrial alcohol Ethyl alcohol High quality- similar to confectionary
Bakery Bread etc. High quality-similar to textiles
Source : Food Research Institute, Ghana
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2.6. UTILIZATION OF CASSAVA
2.6.1. Food Uses
The food industry is one of the largest consumers of starch and starch products (FAO,
2007). Native starch, modified starch and glucose are used in the food industry for one or
more of the following purposes:
Directly as cooked starch food, custard and other forms;
Thickener using the pasting properties of starch (soups, baby foods, sauces and
gravies, etc.;
Filler contributing to the solid content of soups, pills and tablets and other
pharmaceutical products.
Binder, used to consolidate the mass and prevent it from drying out during cooking
(sausages and processed meats);
Stabilizer, owing to the high water-holding capacity of starch.
Cassava is mainly composed of starch (carbohydrates) - the source of energy, fibre,
minerals and vitamins. The roots have very low protein in comparison with cereals and this
forms the common criticism of cassava roots. Some varieties of cassava that have yellow
fleshed roots have been reported to contain beta-carotene in their composition, a precursor
of vitamin A (Chitundu, 2009).
Table 2.5: Nutrient Composition of Fresh Cassava Roots (per 100g of edible portion)
Nutrient Quantity
Energy-(kcal) 146
Water (g) 62.5
Carbohydrate-(g) 34.7
Protein-(g) 1.2
Fat-(g) 0.3
Vitamin A- (I.U) Trace
Thiamine, Vit. B1- (mg) 0.06
Riboflavin, Vit. B2- (mg) 0.03
Niacin- (mg) 0.06
Vitamin C (mg) 36
Source: FAO Food Composition Table
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2.6.2. Non-food Uses
Starch makes a good natural adhesive (FAO, 2007). There are two types of adhesives
made from starch, (i) roll-dried adhesives and (ii) liquid adhesives. The following are some of
the major uses of starch derived adhesives in non-food industries.
Corrugated cardboard manufacture.
Remoistening gums.
Wallpaper and other home uses.
Well drilling.
Paper industry.
Textile industry.
Wood furniture.
The table 2.6 shows the specifications for HQCF for paperboard adhesives and plywood
glue extenders.
Table 2.6: Specification for flour (starch) used for paperboard adhesives and plywood
glue extenders
Parameter Requirements
Appearance and uniformity Colour should be uniform white and free from any specs
Milled Finely milled
Odour Odourless
Moisture content 10-12%
Ash content
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CHAPTER 3
3.0. MATERIALS AND METHODS
3.1. MATERIALS
Fresh raw cassava varieties were collected from two provinces, Luapula and Lusaka. Ten
(10) cassava varieties were collected from Luapula, Mansa district in particular, at the
Zambia Agriculture Research Institute (ZARI). These comprised two (2) local and eight (8)
improved varieties.
3.1.1. Apparatus and Equipment
Spectrophotometer
Kjeldhal digestion unit, Kjeldhal flasks and distillation unit
Mechanical hot air drier or dehydrator
One analytical block with 24 bores and a lid (cyanide determination)
Detection plates (cyanide determination)
Electric water bath
Furnace
Crucibles for ashing
Oven for moisture determination
Soxhlet extraction unit
Volumetric flasks (1000ml, 500ml, and 100ml)
Pipettes (0-200l, 1ml, 5ml, and 25ml)
Steel dishes for moisture content
3.1.2. Reagents
Boric acid indicator
Concentrated Sulphuric acid (95-97%, H2SO4 )
0.1N Hydrochloric acid (HCl)
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10M, 1.0N, Sodium hydroxide (NaOH)
Petroleum ether
Concentrated ethanol (95-97%)
Stock Iodine solution and Iodine reagent
0.1M Phosphoric acid (H3PO4), 0.132M ortho-Potassium dihydrogen Phosphate
(KH2PO4), 0.132M ortho-di-Sodium Hydrogen Phosphate (Na2HPO4)
Pectinase enzyme (from Rhizopus spp.)
3.2. METHODS
3.2.1. Experimental Design and Sampling
Raw cassava tubers were collected from two locations, Lusaka and Luapula. These tubers
consisted of both local and improved varieties. The HQCF was produced from these
varieties and physico-chemical analysis was conducted. A comparison was made to
determine whether differences existed between local and improved varieties. The
quantitative variables that were measured to facilitate this comparison were; ash content,
moisture content, protein content, amylose content, crude oil content and cyanide content.
3.2.2. Statistical Analysis
A t-test was used to determine whether there were true differences between the local and
improved cassava varieties and a one-way analysis of variance (ANOVA) was used to
determine whether there were any differences among the individual varieties. In all cases,
= 0.05 was used.
A statistical tool, QI MACROS 2012, was used for both the t-test and the one-way ANOVA.
The graphs appearing were generated using Microsoft excel.
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3.2.3. Production of High Quality Cassava Flour (HQCF)
Fresh mature tubers which were collected from the named areas were processed as follows.
Firstly, the raw whole tubers were rinsed using tap water to remove surface soil before the
actual processing was carried out. The processing steps are outlined below:
3.2.3.1. Peeling
The tubers were peeled using stainless steel knives. Adequate peeling was ensured to avoid
peel fragments in the final product which would otherwise affect the subsequent analysis.
3.2.3.2. Washing
Washing was carried out in a clean pail using clean tap water to remove dirt and other
particles that adhered to the peeled tuber.
3.2.3.3. Slicing and chipping
A manually designed cassava chipper was used to reduce the sizes of the tuber in order to
hasten the drying process as well as release some of the cyanide in the tuber. The cassava
chips were then placed on trays and weighed so as to determine the amount of water that
was being removed during the drying process. After weighing, the trays were then placed in
the drier.
3.2.3.4. Drying
The drying process was conducted at a temperature of 60 for 5-7 hours by use of a
mechanical air drier. After the time had elapsed, the dry cassava chips were then weighed
and the amount of water that was removed was calculated by subtracting the weight of the
dry chips from the weight of the wet ones.
Moisture removed (%) =
100
3.2.3.5. Milling and Sieving
The dried chips were milled using a blender to a fine powder. The flour was then sieved
using a 0.5mm sieve. The resultant flour was High Quality Cassava Flour (HQCF).
3.2.3.6. Packaging
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The flour was then packaged in small black polyethylene bags as prescribed in literature
(Chitundu, 2009).
3.2.3.7. Process overview
The process flow diagram from the raw cassava to the High Quality Cassava Flour is shown
in figure 3.1;
Fig 3.1: Process flow diagram for production of High Quality Cassava Flour (HQCF)
3.2.4. Physico-Chemical analysis
The ash content, fat content, and moisture content was determined based on the method
prescribed by AOAC (1990).
3.2.4.1. Protein determination
The protein content for all the cassava varieties was analysed using the Kjeldhal method.1 g
of the sample (HQCF) was weighed into the Kjeldhal flask. Then, 6g of the catalyst was
weighed and also added to the flask. 12ml of sulphuric acid was then added to the mixture.
The flasks were then put into the digestion unit and the samples were digested for 1 hour.
After digestion and cooling, to the acid digest, 75 ml of distilled water was added. 50ml of
sodium hydroxide was added to the cooled, diluted digest. The Kjeldhal flask was connected
Fresh cassava
Peeling and washing
Cutting and Chipping
Drying (60c for 5-7
hours)
Milling and Sieving
(0.5mm)
HQCF
Peel fragments and waste water
Waste
fibre
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to the distillation unit and the distillate was collected in a receiving flask containing 25ml
boric acid indicator solution for 5 minutes. The content of the receiving flask was then titrated
with 0.1N HCl to the first pink colour. A blank test was carried out following the same
procedure as the sample but 5ml of distilled water was used.
The protein content was calculated as follows:
Crude protein (%) = .(.)().
Where;
Vs. = volume of 0.1N HCl used for the sample.
Vb. = volume of 0.1N HCl used for the blank.
wt. = weight of the sample used for protein digest.
5.70 = conversion factor for flour.
3.2.4.2. Crude fat determination
The fat content was determined by weighing 5g of the sample (HQCF) on a dry filter paper,
folded and transferred to an extraction thimble, and then plugged lightly with cotton wool. A
dry extraction flask was weighed, and to it, 200ml of extraction solvent (petroleum ether) was
added. The Soxhlet extractor was then assembled and the fat was extracted for 6-7 hours.
After the time had elapsed, the solvent was then evaporated with the rotary evaporator and
the fat residue was dried until constant weight at 105, the flask was then cooled down in a
desiccator and then weighed.
The percent crude fat was calculated as follows:
Fat (%) = ()
100
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Where;
G1= is the mass, in grams, of the test portion (sample)
G2 = is the mass, in grams, of the dry extraction flask
G3 = is the mass, in grams, of the extracted fat + extraction flask.
3.2.4.3. Ash determination
The ash content was determined by weighing 2g of the sample (HQCF) into crucibles. The
crucibles were then transferred to a muffle furnace, which was heated to about 550. The
sample was ashed for 4 hours. After the 4 hours had elapsed, the furnace was then cooled
to 100; the crucibles were removed and placed in a desiccator. After 30 minutes in the
desiccator, the crucibles were weighed and the ash percent was calculated as follows:
Ash (%) =
100
Where;
A = weight of ignited crucible (g)
B = weight of ignited crucible + sample (g)
B-A = weight of sample
C = weight of crucible + ash
3.2.4.4. Moisture determination
Two dishes with their covers were weighed and 2g of the air dry sample (HQCF) was placed
into the dishes and again weighed. The covers were then loosened and placed in the oven
for 1 hour at 120. The dishes were then removed from the oven, the covers tightened and
cooled in a desiccator for 20 minutes. After the 20 minutes, the dry samples were removed
from the desiccator and weighed. The moisture content was calculated as follows:
Moisture (%) =
100
Hence, dry matter content = 100 - moisture
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Where;
A = weight of dish + cover (g)
B = weight of dish + cover + sample (g)
B A = weight of sample
C = weight of dry sample + dish + cover
3.2.4.5. Amylose determination
This was determined using the method of Williams et al, (1958) involving the preparation of
stock iodine solution and iodine reagent. First 0.1g of the HQCF was weighed into a 100ml
volumetric flask, and then 1ml of 99.7 100% (v/v) ethanol and 9ml 1N sodium hydroxide
(NaOH) were added. The mouth of the flask was covered with aluminium foil and the
contents mixed. The samples were then boiled for 10 minutes in a boiling water bath to
gelatinize the starch. The time was recorded from the onset of boiling. The samples were
then removed from the water bath and allowed to cool. They were made up to the mark with
distilled water and thoroughly shaken. 5ml of the aliquot was pipetted into another 100ml
volumetric flask, 1 ml of 1N acetic acid and 2 ml of iodine solution was added. The flask was
then filled up to the mark with distilled water. Absorbance was read using a
Spectrophotometer at 620nm. The blank containing 1ml of ethanol and 9ml of 1N sodium
hydroxide was boiled, cooled and filled up to the mark with distilled water. A portion (5ml) of
the mixture was then pipetted into a 100ml volumetric flask. 1ml of 1N acetic acid and 2ml of
iodine solution was added and then filled up to the mark with distilled water. This was used
to standardize the spectrophotometer at 620nm. The amylose content was calculated as
follows:
Amylose (%) = 3.06 A d.f
Where;
A= absorbance,
d.f= dilution factor (20), and
3.06= constant.
3.2.4.6. Cyanide determination
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Cyanide determination was done using the method of Brimer and Molgaard (1986) or the
quant scan method. 50g of the sample (HQCF) was mixed in a blender with 200ml of 0.1M
Phosphoric acid (H3PO4) for about 1 minute. The mixture was placed in a 250ml beaker and
left to stand until a clear separation of the mixture was observed. The supernatant was then
put in an analytical block in proportions of 10, 50,100 and 150 l by use of a micro pipette.
1ml of potassium sodium buffer was then added to each of the proportions. 100 l of the
pectinase enzyme was then added to each. The picrate sheet was immediately placed over
the block and incubated overnight. The picrate sheet was then analysed by use of quant
scan software and the cyanide content was reported in mg/kg.
The same procedure was used for the raw cassava but160ml of the extraction medium
(0.1M Phosphoric acid) was used instead of the 200ml.
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CHAPTER 4
4.0. RESULTS AND DISCUSSION
The objective of the research project was to characterize HQCF produced from local and
improved cassava varieties. This was achieved by determining the proximate composition,
the cyanide content and the amylose content of the HQCF produced from each cassava va-
riety.
4.1. CASSAVA VARIETIES
A survey was conducted on the types of local and improved cassava varieties available in
Zambia. Some of the local varieties and improved varieties that are available in Lusaka
(Chongwe) and Luapula (Mansa) are shown in table 4.1.
Table 4.1: Varieties collected from different parts of Zambia
VARIETY
LOCATION
Lusaka Luapula
Improved Nalumino Bangweulu, Chila, Kariba, Kapumba,
Kampolombo, Tanganyika, Mweru, and
Nalumino
Local Lipalumusi, Linangwa, Kamuliboko, and
Nakamoya
Namunyongo and Katobamputa
4.1.1. Photos of selected Cassava Varieties
Figure 4.1: Photo of improved and local cassava variety
4.2. Determination of Moisture Content for both Raw Cassava and HQCF
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4.2.1. Moisture Content of Raw Cassava
Samples of raw cassava from Mansa were analysed for moisture content in triplicate. These
were found to be; Kampolombo (68.171.5%), Chila (66.031.6%), Tanganyika
(66.761.2%), Katobamputa (60.311.5%), Namunyongo (61.251.2%), Kariba
(60.831.6%), Nalumino (50.681.1%), Bangweulu (61.741.0%), Kapumba (57.081.0%)
and Mweru (58.20.8%), as shown in figure 4.2.
Figure 4.2: Graph of moisture content for raw cassava (Mansa)
The moisture content for Kampolombo, Chila and Tanganyika were above the literature val-
ue of 62% that was reported by Onwueme (1983). Namunyongo, Kariba, Katobamputa and
Bangweulu were closer to this value while Kapumba, Nalumino and Mweru were below as
shown in figure 4.2.
0.0010.0020.0030.0040.0050.0060.0070.0080.00
Mo
istu
re C
on
ten
t (%
)
Variety
Moisture Content of Raw Cassava (Mansa)
Email: [email protected]; [email protected]
The mean moisture content for the improved varieties was compared with that for the local
varieties as shown in figure 4.3. The mean moisture content of the local varieties was lower
than the improved varieties.
Figure 4.3: Graph of moisture content of raw cassava varieties (local and improved)
A t-test was used to determine whether there were differences between the two varieties (lo-
cal and improved). A value of P = 0.927 was obtained which showed that P> 0.05, and thus,
there was no significant difference in the mean moisture content between the two varieties.
The means for the improved and local varieties were compared to the literature value as
shown in figure 4.4. The mean for the improved varieties was higher than that for the local
varieties and closer to the literature value.
Figure 4.4: Graph of moisture content of raw cassava varieties and literature value
60
60.2
60.4
60.6
60.8
61
61.2
61.4
61.6
Local Improved
Mo
istu
re C
on
ten
t (%
)
Variety
Mean Moisture Content of Raw Local and Improved
Cassava Varieties
Local
Improved
5959.5
6060.5
6161.5
6262.5
63
Local Improved Liter.value.
(Onwueme, 1983)
Mois
ture
Con
ten
t (
%)
Variety
Mean Moisture Content of Raw Cassava Varieties against
Literature Value
Local
Improved
Liter.value. (Onwueme, 1983)
Email: [email protected]; [email protected]
4.2.2. Moisture Content of HQCF
Samples of HQCF produced from both Mansa and Chongwe cassava varieties were ana-
lysed for moisture content in triplicate. Those from Mansa were found to be; Kampolombo
(7.430.85%), Chila (8.430.23%), Tanganyika (7.380.83%), Katobamputa (7.550.24%),
Namunyongo (8.251.16%), Kariba (5.271.4%), Nalumino (6.090.74%), Bangweulu
(4.660.7%), Kapumba (6.300.75%) and Mweru (3.930.45%), as shown in figure 4.5.
Figure 4.5: Graph of moisture content for HQCF from local and improved varieties
The moisture content for all the varieties were all below the moisture content level of 13%
maximum which is recommended by ZABS (2008) as shown in Figure 4.5.
Hence, this showed that the temperature-time combination of 60 for 6 hours used in the
drying stage as recommended by Boateng (2007) was effective in reducing the moisture
content to acceptable levels.
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Mo
istu
re C
on
ten
t (%
)
Variety
Moisture Content of HQCF (Mansa)
Email: [email protected]; [email protected]
The moisture content for the varieties from Chongwe were found to be; Linangwa (6.7
0.18%), Nakamoya (6.8 0.5%), Kamuliboko (5.73 0.11%), Lipalumusi (9.340.08%) and
Nalumino (6.8 0.24%), as shown in figure 4.6.
Figure 4.6: Graph of moisture content for HQCF from local and improved varieties
From figure 4.6, the moisture content for all the varieties was below the moisture content
level of 13% maximum stipulated by ZABS (2008).
Hence, this showed that the temperature-time combination of 60 for 6 hours used in the
drying stage as recommended by Boateng (2007) was effective in reducing the moisture
con-tent to acceptable levels.
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Linangwa Nakamoya Nalumino Kamuliboko Lipalumusi CODEX standard
Mo
istu
re C
on
ten
t (
%)
Variety
Moisture Content for HQCF (Chongwe)
Email: [email protected]; [email protected]
4.3. Ash Content of HQCF
Samples of HQCF were analysed for ash content in triplicate. The ash content for the varie-
ties from Mansa were found to be; Kampolombo (2.630.05%), Chila (1.180.25%), Tan-
ganyika (3.590.04%), Katobamputa (1.760.1%), Namunyongo (1.800.04%), Kariba
(1.830.04%), Nalumino (2.620.1%), Bangweulu (1.850.01%), Kapumba (1.660.1%) and
Mweru (1.540.36%), as shown in figure 4.7.
Figure 4.7: Graph of ash content for HQCF from local and improved varieties (Mansa)
The ash content for all the varieties except Tanganyika, were below the maximum ash con-
tent of 3% stipulated by ZABS (2008). However, the ash content of greater than 3% is not
unusual for cassava. Maziya (2003) reported an ash content of 4.30.28% when determining
the effect of drying methods on the physico-chemical properties of HQCF from yellow cassa-
va roots.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Ash
C
on
ten
t (%
)
Variety
Ash Content for HQCF (Mansa)
Email: [email protected]; [email protected]
The ash content for the individual improved varieties were compared to determine whether
there were any differences among the varieties as shown in figure 4.8. Tanganyika had the
highest ash content (3.590.04%) while Chila had the lowest (1.180.25%).
Figure 4.8: Graph of ash content for improved cassava varieties (Mansa)
A one-way analysis of variance (ANOVA) was used and a P value = 0.0 was obtained which
showed that P < 0.05, and hence, there were significant differences in the ash content
among the individual improved varieties.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
Ash
Co
nte
nt
(%)
Variety
Ash Content of HQCF from Improved Cassava Varieties
Email: [email protected]; [email protected]
The mean ash content for both improved and local cassava varieties were compared as
shown in figure 4.9. The mean ash content for the local varieties was lower than the im-
proved varieties.
Figure 4.9: Graph of ash content of HQCF from local and improved cassava varieties
A t-test was used to determine whether they were differences between the two means. A P
value = 0.392 was obtained which showed that P > 0.05, and hence, there were no signifi-
cant differences in the means of the two varieties.
The mean ash content for both local and improved cassava varieties were compared with
the literature value as shown in figure 4.10. The two varieties were comparatively similar and
were below 3% maximum ash content stipulated by ZABS (2008).
Figure 4.10: Graph of ash content of cassava varieties against literature value (Mansa)
1.7
1.8
1.9
2
2.1
2.2
2.3
Local Improved
Ash
Co
nte
nt
(%)
Variety
Mean Ash Content for Local and Improved Cassava
Varieties (Mansa)
Local
Improved
0
0.5
1
1.5
2
2.5
3
3.5
Local Improved CODEX standard
(Max)
Ash
Con
ten
t (%
)
Variety
Ash Content of Cassava Varieties against Literature Value
Local
Improved
CODEX standard (Max)
Email: [email protected]; [email protected]
The ash content of HQCF for the varieties from Chongwe were found to be; Linangwa (2.67
0.25%), Nakamoya (2.74 0.27%), Kamuliboko (2.82 0.32%), Lipalumusi (2.53 0.05%)
and Nalumino (2.85 0.27%), as shown in figure 4.11. All the varieties were close to the
maximum ash content of 3% stipulated by ZABS (2008).
Figure 4.11: Graph of ash content of HQCF (Chongwe)
The mean ash content for the local varieties and the improved variety was compared to the
literature value as shown in figure 4.12.
Figure 4.12: Graph of ash content of cassava varieties against literature value
Both varieties were just below the recommended maximum value of 3% ash content stipu-
lated by ZABS (2008).
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Linangwa Nakamoya Nalumino Kamuliboko Lipalumusi CODEX standard
Ash
C
on
ten
t (%
)
Variety
Ash Content for HQCF
0
0.5
1
1.5
2
2.5
3
3.5
Local Improved CODEX standard
(Max)
Ash
Con
ten
t (%
)
Variety
Mean Ash Content of Chongwe Cassava Varieties
against Literature Value
Local
Improved
CODEX standard (Max)
Email: [email protected]; [email protected]
The ash content for the local varieties from both Chongwe and Mansa were compared as
shown in figure 4.13.
Figure 4.13: Graph of ash content HQCF from Local Varieties (Chongwe and Mansa)
From figure 4.13, the ash content for all the Chongwe local varieties were higher than those
from Mansa.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Kat
ob
ampu
ta
Nam
uny
ong
o
Lin
ang
wa
Nak
amoy
a
Kam
uli
bok
o
Lip
alu
mu
si
Mansa Chongwe
Ash
C
on
ten
t (%
)
Variety
Comparison of Ash Content of Chongwe and Mansa
Local Varieties
Mansa Katobamputa
Mansa Namunyongo
Chongwe Linangwa
Chongwe Nakamoya
Chongwe Kamuliboko
Chongwe Lipalumusi
Email: [email protected]; [email protected]
The mean ash content for the local varieties from Mansa and Chongwe were compared as
shown in figure 4.14. The mean ash content for the Chongwe local varieties was higher than
the Mansa local varieties.
Figure 4.14: Graph of ash content of HQCF from local varieties (Chongwe and Mansa)
A t-test was conducted to determine whether differences existed between the means for the
local varieties from the two locations. A P value = 0 was obtained which showed that P <
0.05, and hence, there was a significant difference between the means for the local varieties
from the two locations.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Chongwe Mansa
Ash
Co
nte
nt
(%)
Location
Mean Ash Content of Chongwe and Mansa Local
Varieties
Chongwe
Mansa
Email: [email protected]; [email protected]
4.4. Amylose Content of HQCF
Samples of HQCF were analysed for amylose content in triplicate. The amylose content for
the varieties from Mansa were found to be; Kampolombo (16.70.01%), Chila (16.90.01%),
Tanganyika (15.50.02%), Katobamputa (16.80.05%), Namunyongo (19.00.1%), Kariba
(16.30.01%), Nalumino (15.70.01%), Bangweulu (15.60.03%), Kapumba (15.30.02%)
and Mweru (170.04%), as shown in figure 4.15.
Figure 4.15: Graph of amylose content for HQCF (Mansa)
The amylose content for Kampolombo, Chila, Katobamputa, Namunyongo, Kariba and Mwe-
ru were within the range of the literature value of 16-21% reported by Nuwamanya et al,
2010, while Tanganyika, Nalumino, and Kapumba were below this range.
The amylose content for each individual improved cassava variety was compared to deter-
mine whether there were any differences among individual improved cassava varieties as
0.00
5.00
10.00
15.00
20.00
25.00
Am
ylo
se C
on
ten
t (%
)
Variety
Amylose Content for HQCF (Mansa)
Email: [email protected]; [email protected]
shown in figure 4.16. Mweru had the highest amylose content of 170.04% while Kapumba
had the lowest with 15.30.02%.
Figure 4.16: Graph of Amylose content for improved cassava varieties (Mansa)
A one-way ANOVA was used and a value of P = 0.032 was obtained which showed that P <
0.05, and hence, there were significant differences in the amylose content among the means
of the individual improved cassava varieties from Mansa.
13.50
14.00
14.50
15.00
15.50
16.00
16.50
17.00
17.50
Am
ylo
se C
on
ten
t (%
)
Variety
Amylose Content of Improved Cassava Varieties
Email: [email protected]; [email protected]
The mean amylose content of HQCF for both improved and local varieties were compared
as shown in figure 4.17. The mean amylose content for the local varieties was higher than
the improved varieties.
Figure 4.17: Graph of amylose content of local and improved cassava varieties
(Mansa)
A t-test was used to determine whether there were differences in the amylose content be-
tween the two varieties (improved and local) and a value of P = 0.015 was obtained which
showed that P < 0.05, and hence, there were significant differences between the two varie-
ties.
0
2
4
6
8
10
12
14
16
18
20
Local Improved
Am
ylo
se C
on
ten
t (%
)
Variety
Mean Amylose Content for Local and Improved Cassava
Varieties
Local
Improved
Email: [email protected]; [email protected]
The mean amylose content for the local and improved varieties were compared to the litera-
ture value as shown in figure 4.18.
Figure 4.18: Graph of amylose content of Mansa cassava varieties and literature value
From figure 4.18, the mean for the local varieties was higher than that for the improved va-
rieties and close to the literature value of 18.5% that was reported by Nuwamanya (2010).
0
5
10
15
20
25
Local Improved liter. value
(Nuwamanya et al,
2010)
Am
ylo
se C
on
ten
t (%
)
Variety
Amylose Content of Cassava Varieties against Literature
Value
Local
Improved
liter. value (Nuwamanya et al,
2010)
Email: [email protected]; [email protected]
The amylose content for the varieties from Chongwe were found to be; Linangwa
(15.21.4%), Nakamoya (14.553.32%), Kamuliboko (13.773.29%), Lipalumusi
(16.50.98%) and Nalumino (18.752.5%), as shown in figure 4.19.
Figure 4.19: Graph of amylose content for HQCF (Chongwe)
From figure 4.19, only Lipalumusi and Nalumino had amylose content within the range of the
literature value, the rest were below the range of the literature value of 16- 21% amylose
content reported by Nuwamanya et al, 2010. Nalumino was the highest with 18.752.5%
while Kamuliboko was the lowest with 13.773.29%.
0
5
10
15
20
25
Linangwa Nalumino Nakamoya Kamuliboko Lipalumusi Liter.Value
Am
ylo
se
Co
nte
nt
(%)
Variety
Amylose Content of HQCF (Chongwe)
Linangwa
Nalumino
Nakamoya
Kamuliboko
Lipalumusi
Liter.Value
Email: [email protected]; [email protected]
The amylose content for the local varieties from Chongwe and Mansa was compared to
determine whether differences existed as shown in figure 4.20.
Figure 4.20: Graph of amylose content for local varieties (Chongwe and Mansa)
From figure 4.20, it was observed that Lipalumusi and Katobamputa had similar amylose
content. Namunyongo had a higher content of 19.00.1% than the other varieties.
Amylose together with amylopectin constitutes starch. These polymers are very different
structurally, amylose being linear and amylopectin highly branched - each structure has
been known to play a critical role in the ultimate functionality of the native starch and its de-
rivatives (Morton, 2007). There ratio has been known to influence the functional characteris-
tics of starch such as gel strength, viscosity, solubility, pasting properties etc. According to a
study that was conducted by Gonzalez et al (2003) on the amylographic performance of
cassava starch subjected to extrusion cooking, it was observed that cassava varieties with
different amylose content had different gelatinization temperatures. Those with high amylose
content had low gelatinization temperatures than those with low amylose content.
0.00
5.00
10.00
15.00
20.00
25.00
Kat
obam
puta
Nam
unyongo
Lin
angw
a
Nak
amoya
Kam
uli
boko
Lip
alum
usi
Mansa Chongwe
Am
ylo
se C
on
ten
t (%
)
Variety
Amylose Content of HQCF from Chongwe and Mansa
Local Varieties
Mansa Katobamputa
Mansa Namunyongo
Chongwe Linangwa
Chongwe Nakamoya
Chongwe Kamuliboko
Chongwe Lipalumusi
Email: [email protected]; [email protected]
The mean amylose content for the local varieties from Chongwe and Mansa was compared
as shown in figure 4.21. The mean amylose content for the local varieties from Mansa was
higher than the local varieties from Chongwe.
Figure 4.21: Graph of amylose content of HQCF from local varieties (Chongwe and
Mansa)
A t-test was conducted to determine whether there was a significant difference between the
two varieties and a P value = 0.029 was obtained which showed that P < 0.05, and hence,
there was a significant difference between the varieties from the two locations.
0.00
5.00
10.00
15.00
20.00
25.00
Chongwe Mansa
Am
ylo
se C
on
ten
t (%
)
Location
Mean Amylose Content of HQCF from Chongwe
and Mansa Local Varieties
Chongwe
Mansa
Email: [email protected]; [email protected]
4.5. Protein Content of HQCF
Samples of HQCF were analysed for protein content in duplicate. The protein content for the
varieties from Mansa were found to be; Kampolombo (1.040.11%), Chila (0.760.05%),
Tanganyika (4.20.58%), Katobamputa (0.790.44%), Namunyongo (1.350.1%), Kariba
(1.170.19%), Nalumino (1.020.12%), Bangweulu (1.60.12%), Kapumba (1.230.16%)
and Mweru (0.970.04%), as shown in figure 4.22.
Figure 4.22: Graph of protein content of HQCF (Mansa)
From figure 4.22, the protein content for all the varieties except Tanganyika were lower than
the literature value of 2% reported by Onwueme (1983).
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
Pro
tein
Co
nte
nt
(%)
Variety
Protein Content of HQCF (Mansa)
Email: [email protected]; [email protected]
The protein content for the individual improved cassava varieties were compared to deter-
mine whether there were any differences among the varieties as shown in figure 4.23. The
protein content ranged from 4.2-0.7% with Tanganyika having the highest and Chila the low-
est. The mean protein content for the improved cassava varieties was found to be
1.52.36%.
Figure 4.23: Graph of protein content of improved cassava varieties (Mansa)
A one-way ANOVA was conducted to determine whether there were differences in the pro-
tein content among the individual improved varieties, and a value of P = 0.00 was obtained
which showed that P < 0.05, and hence, there were significant differences in the protein con-
tent among the individual improved varieties.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
Pro
tein
Co
nte
nt
(%)
Variety
Protein Content of HQCF from Improved Cassava
Varieties
Email: [email protected]; [email protected]
The mean protein content for the improved varieties was compared with that for the local
varieties as shown in figure 4.24. The mean protein content of the improved varieties was
higher than the local varieties.
Figure 4.24: Graph of protein content of HQCF from local and improved varieties
A t-test was used and a value of P = 0.313 was obtained which showed that P > 0.05, and
hence, there were no significant differences between the two varieties (local and improved)
from Mansa.
The mean protein content for the local varieties and the improved varieties were compared
to the literature value as shown in figure 4.25.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Local Improved
Pro
tein
Co
nte
nt
(%)
Variety
Mean Protein Content of HQCF for Local and
Improved Cassava Varieties
Local
Improved
Email: [email protected]; [email protected]
Figure 4.25: Graph of protein content of cassava varieties and literature value (Mansa)
The mean protein content for the improved varieties was higher than the local varieties and
close to the literature value. However, both varieties were below the reported literature value
of 2 % by Onwueme (1983).
The protein content of HQCF for the varieties from Chongwe were; Linangwa (1.520.36%),
Nakamoya (0.980.29%), Kamuliboko (1.060.07%), Lipalumusi (1.130.06%) and Nalumi-
no (1.980.37%), as shown in figure 4.26.
0
0.5
1
1.5
2
2.5
Pro
tein
C
on
ten
t (%
)
Variety
Protein Content of Cassava Varieties against Literature
Value
Local
Improved
Liter. Value(Onwueme, 1983)
Max
Email: [email protected]; [email protected]
Figure 4.26: Graph of protein content of HQCF (Chongwe)
The protein content for the varieties from Chongwe varied greatly. Nakamoya, Kamuliboko,
and Lipalumusi were lower than the literature value while Nalumino was higher than the lit-
erature value of 2% reported by Onwueme (1983).
0.00
0.50
1.00
1.50
2.00
2.50
Linangwa Nalumino Nakamoya Kamuliboko Lipalumusi liter.Valuemax
pro
tein
Co
nte
nt
(%)
Variety
Protein Content of HQCF (Chongwe)
Email: [email protected]; [email protected]
The protein content for the local varieties from both locations was compared as shown in
figure 4.27.
Figure 4.27: Graph of protein content for local varieties (Chongwe and Mansa)
From figure 4.27, it was observed that Linangwa had higher protein content of 1.520.36%,
than the other local varieties and Katobamputa had the lowest protein content of
0.790.44%.
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80K
ato
bam
pu
ta
Nam
uny
ong
o
Lin
ang
wa
Nak
amoy
a
Kam
uli
bok
o
Lip
alu
mu
si
Mansa Chongwe
Pro
tein
Co
nte
nt
(%)
Variety
Protein Content of Chongwe and Mansa Local varieties
Mansa Katobamputa
Mansa Namunyongo
Chongwe Linangwa
Chongwe Nakamoya
Chongwe Kamuliboko
Chongwe Lipalumusi
Email: [email protected]; [email protected]
The mean protein content for the local varieties from Chongwe and Mansa were compared
as shown in figure 4.28. The mean protein content for the Mansa local varieties was lower
than that for the Chongwe varieties.
Figure 4.28: Graph of mean protein content for local varieties (Chongwe and Mansa)
A t-test was conducted to determine whether differences existed between the local varieties
from the two locations and a P value = 0.36 was obtained which showed that P > 0.05, and
hence, there was no significant difference between the local varieties from the two locations.
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
Chongwe Mansa
Pro
tein
C
on
ten
t (%
)
Location
Mean Protein Content for Chongwe and Mansa Local
Varieties
Chongwe
Mansa
Email: [email protected]; [email protected]
4.6. Fat Content of HQCF
Samples of HQCF were analysed for fat content in a single run. The fat content for the varie-
ties from Mansa were found to be; Kampolombo (1.60%), Chila (0.34%), Tanganyika
(0.78%), Katobamputa (0.28%), Namunyongo (0.48%), Kariba (0.40%), Nalumino (0.74%),
Bangweulu (0.30%), Kapumba (0.80%) and Mweru (0.50%) as shown in figure 4.29.
Figure 4.29: Graph of fat content of HQCF (Mansa)
From figure 4.29, the fat content of all the varieties was in consonant with the reported max-
imum fat content of 3% by Onwueme (1983). All the varieties had a fat content of less than
1%, with an exception of Kampolombo which had a higher fat content of 1.6%.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Fa
t C
on
ten
t (
%)
Variety
Fat Content of HQCF (Mansa)
Email: [email protected]; [email protected]
The mean fat content for the improved varieties was compared with the local varieties as
shown in figure 4.30. The mean fat content for the improved varieties was higher than the
local varieties.
Figure 4.30: Graph of fat content of HQCF from local and improved varieties (Mansa)
To determine whether there were differences in the fat content between the two varieties
(local and improved), a t-test was used. A value of P = 0.199 was obtained which showed
that P > 0.05, and hence, there was no significant difference in the fat content between the
means for the two varieties from Mansa.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Local Improved
Fa
t C
on
ten
t (%
)
Variety
Mean Fat Content of HQCF from Local and Improved
Cassava Varieties
Local
Improved
Email: [email protected]; [email protected]
The mean fat content of local and improved cassava varieties was compared with the litera-
ture value as shown in figure 4.31.
Figure 4.31: Graph of fat content of cassava varieties against literature value (Mansa)
The fat content for both the varieties were below the reported fat content of cassava by
Onwueme (1983), as shown in figure 4.31.
0
0.5
1
1.5
2
2.5
3
3.5
Local Improved literature value
(Onwueme, 1983)
max
Fa
t C
on
ten
t (
%)
Variety
Mean Fat Content of Cassava Varieties against
Literature Value
Local
Improved
literature value (Onwueme,
1983) max
Email: [email protected]; [email protected]
The fat content of HQCF for the varieties from Chongwe were found to be: Linangwa
(0.80%), Nakamoya (0.70%), Kamuliboko (0.92%), Lipalumusi (0.42%) and Nalumino
(0.54%), as shown in figure 4.32.
Figure 4.32: Graph of fat content of HQCF (Chongwe)
All the varieties were below the reported maximum value of 3% by Onwueme (1983).
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Linangwa Nalumino Nakamoya Kamuliboko Lipalumusi liter. Value
Fa
t C
on
ten
t (%
)
Variety
Fat Content of HQCF (Chongwe)
Linangwa
Nalumino
Nakamoya
Kamuliboko
Lipalumusi
liter. Value
Email: [email protected]; [email protected]
The fat content for the local varieties from both locations was compared as shown in figure
4.33.
Figure 4.33: Graph of fat content of HQCF for local varieties (Chongwe and Mansa)
From figure 4.33, it was observed that Linangwa, Kamuliboko and Nakamoya had a high fat
content than Katobamputa and Namunyongo. Lipalumusi had a similar fat content with the
two varieties from Mansa.
0.00
0.20
0.40
0.60
0.80
1.00
1.20
Kat
ob
ampu
ta
Nam
uny
ong
o
Lin
ang
wa
Nak
amoy
a
Kam
uli
bok
o
Lip
alu
mu
si
Mansa Chongwe
Fa
t C
on
ten
t (%
)
Variety
Fat Content of HQCF from Chongwe and Mansa Local
Varieties
Mansa Katobamputa
Mansa Namunyongo
Chongwe Linangwa
Chongwe Nakamoya
Chongwe Kamuliboko
Chongwe Lipalumusi
Email: [email protected]; [email protected]
The mean fat content for the local varieties from Chongwe was compared with the Mansa
local varieties as shown in figure 4.34. The mean fat content for Chongwe local varieties was
higher than the Mansa local varieties.
Figure 4.34: Graph of mean fat content for local varieties (Chongwe and Mansa)
A t-test was conducted to determine whether there were differences between the means of
the local varieties from the two locations and a P value = 0.07 was obtained which showed
that P > 0.05, and hence, there was no significant difference between the local varieties from
the two locations.
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Chongwe Mansa
Fa
t C
on
ten
t (%
)
Location
Mean Fat Content of Chongwe and Mansa Local
Varieties
Chongwe
Mansa
Email: [email protected]; [email protected]
4.7. Cyanide Content of Raw Cassava and HQCF
4.7.1. Cyanide Content of Raw Cassava
Samples of raw cassava were analysed for cyanide content in a single run. The cyanide con-
tent for the varieties from Mansa were found to be; Kampolombo (10.75 mg/kg), Chila (77.84
mg/kg), Tanganyika (13.28 mg/kg), Katobamputa (11.31 mg/kg), Namunyongo (82.39
mg/kg), Kariba (13.54 mg/kg), Nalumino (8.75 mg/kg), Bangweulu (54.96 mg/kg), Kapumba
(9.69 mg/kg) and Mweru (10.05 mg/kg), as shown in figure 4.35.
Figure 4.35: Graph of cyanide content of raw cassava varieties (Mansa)
Namunyongo, Chila and Bangweulu were all in the lethal cyanide level of greater than 50
mg/kg that is stipulated by ZABS (2008).
For the improved varieties: Mweru, Kapumba and Nalumino were within the safe cyanide
level of 10 mg/kg that is recommended by ZABS (2008); while Kariba, Kampolombo, Chila,
Bangweulu and Tanganyika were above the recommended safe cyanide level. However, for
the local varieties, Namunyongo was in the lethal cyanide level while Katobamputa was just
above the safe cyanide level.
0
10
20
30
40
50
60
70
80
90
100
Cy
an
ide
con
ten
t (m
g/k
g)
Variety
Cyanide Content for Raw Cassava
Nalumino
Tanganyika
Namunyongo
Katobamputa
Bangweulu
Chila
Kampolombo
Kapumba
Mweru
Kariba
Email: [email protected]; [email protected]
4.7.2. Cyanide Content of HQCF
Samples of HQCF were analysed for cyanide content in single run. The cyanide content for
the varieties from Mansa were found to be; Kampolombo (8.01 mg/kg), Chila (24.61 mg/kg),
Tanganyika (6.60 mg/kg), Katobamputa (6.98 mg/kg), Namunyongo (29.98 mg/kg), Kariba
(7.64 mg/kg), Nalumino (4.87 mg/kg), Bangweulu (16.79 mg/kg), Kapumba (4.43 mg/kg) and
Mweru (6.22 mg/kg), as shown in figure 4.36.
Figure 4.36: Graph of cyanide content of HQCF (Mansa)
Namunyongo, Bangweulu and Chila were above the recommended safe cyanide level of 10
mg/kg even after processing. However, all the other varieties with an exception of the men-
tioned three were within the safe cyanide level recommended by ZABS (2008).
0
5
10
15
20
25
30
35
Cyan
ide
Co
nte
nt
(mg
/kg
)
Variety
Cyanide Content of HQCF
Nalumino
Tanganyika
Namunyongo
Katobamputa
Bangweulu
Chila
Kampolombo
Kapumba
Mweru
Kariba
Email: [email protected]; [email protected]
The cyanide content for the raw cassava was compared to the cyanide content of HQCF for
each particular variety to determine the percent reduction in cyanide as shown in figure 4.37.
Figure 4.37: Graph of cyanide content (comparison of raw and processed varieties)
From figure 4.37, it was observed that Nalumino, Tanganyika, Katobamputa, Kampolombo,
Kapumba, and Kariba had their cyanide content reduced to safe cyanide level of less than
10mg/kg which is recommended by ZABS (2008), while Namunyongo, Bangweulu and Chila
were still above the safe cyanide level even after processing. The percent reduction in cya-
nide content for these varieties was: Nalumino (44.39%), Tanganyika (50.33%), Na-
munyongo (63.61%), Katobamputa (38.32%), Bangweulu (69.49%), Chila (68.37%), Kam-
polombo (25.5%), Kapumba (54.25%), Mweru (38.07%) and Kariba (43.54%).
It was observed that for the varieties with high cyanide content (Bangweulu, Chila and Na-
munyongo), the reduction in cyanide content was quite high even though it was not sufficient
to render them safe for consumption. In this regard, processing methods that can reduce the
cyanide levels to acceptable levels need to be used. For example, a grater and hydraulic
presses needed to be used to increase cell disruption and increase contact of linamarin with
linamarase, hence, set HCN free.
0
10
20
30
40
50
60
70
80
90
100
Cy
an
ide
Co
nte
nt
(mg
/kg
)
Variety
Comparison of Cyanide Content for Raw and Processed Varieties
(Mansa)
Cyanide Content (Raw)
Cyanide Content
(Processed)
Email: [email protected]; [email protected]
Selected raw cassava varieties were compared with the literature values that were reported
by Sakala, 2004, as shown in figure 4.38.
Figure 4.38: Graph of cyanide content of some improved cassava varieties and litera-
ture values.
All the varieties that were determined in this research were far much below the literature val-
ues that were reported by Sakala (2004). Two different methods were used in determining
the cyanide content. The method that was used by Sakala was called the Prussic Acid anal-
ysis method while the one used in this research project was the quant scan method. The two
methods differ in principle and materials used. In the quant scan method, hydrogen cyanide
is extracted by use of orthophosphoric acid and linamarin is hydrolysed by pectinase en-
zyme which is a convenient source of linamarase activity while in the Prussic acid method,
hydrogen cyanide is extracted by use of distilled water and the hydrolysis of linamarin is de-
pendent on the endogenous enzyme linamarase which is also dependent on cell disruption
for it to be released (Brimer, 2007). Hence, the quant scan method is more reliable than the
prussic acid method.
117.21
85.7191.25
77.84
9.69
54.96
0
20
40
60
80
100
120
140
Chila Kapumba Bangweulu
Cy
an
ide
Co
nte
nt
(mg
/kg
)
Varieties
Comparison of Cyanide Content of Raw Cassava Varieties
and Literature Values
Literature
Determined
Email: [email protected]; [email protected]
The cyanide content for the Chongwe varieties were found to be; Linangwa (5.45 mg/kg),
Nakamoya (6.86 mg/kg), Kamuliboko (7.46 mg/kg), Lipalumusi (6.71 mg/kg) and Nalumino
(5.86 mg/kg), as shown in figure 4.39.
Figure 4.39: Graph of cyanide content of HQCF (Chongwe)
All the varieties were within the safe cyanide level of 10 mg/kg maximum that is recom-
mended by ZABS (2008).
0
2
4
6
8
10
12
Linangwa Nalumino Nakamoya Kamuliboko Lipalumusi CODEX
standard
Cy
an
ide
Co
nte
nt
(mg
/kg
)
Variety
Cyanide Content of HQCF (Chongwe)
Linangwa
Nalumino
Nakamoya
Kamuliboko
Lipalumusi
CODEX standard
Email: [email protected]; [email protected]
CHAPTER 5
5.0. CONCLUSION AND RECOMMENDATIONS
5.1. CONCLUSION
The proximate composition, amylose percent and cyanide content for the High Quality Cas-
sava Flour (HQCF) from both the local and improved cassava varieties were determined,
and a comparison of the physico-chemical composition of the two varieties was also carried
out.
The moisture content of the raw cassava showed no significant differences between local
and improved cassava varieties (P>0.05). It ranged from 68.17-50.68 % with a mean mois-
ture content of 61.091.17%. Kampolombo had higher moisture content while Nalumino had
the lowest. The individual improved varieties differed significantly (P < 0.05).
The ash content of the HQCF for both local and improved showed no significant differences
between local and improved cassava varieties (P> 0.05). Tanganyika had the highest ash
content of 3.590.04% while Chila had the lowest with 1.180.25%. The mean ash content
for all the varieties was found to be 2.080.69%. The ash content for the individual improved
varieties differed significantly (P 0.05). Tanganyika had the highest protein content of 4.20.58% while Chila had
the lowest with 0.760.05%. The mean protein content for all the varieties was found to be
1.411.01%. The individual improved cassava varieties showed a significant difference
(P 0.05).
For the fat content of the HQCF for local and improved, it was found that there were no sig-
nificant differences (P >0.05). The mean fat content for the local varieties was 0.380.41%
while improved was 0.610.4%. The individual improved varieties showed no significant dif-
Email: [email protected]; [email protected]
ference (P >0.05). The local cassava varieties from both locations did not differ significantly
(P > 0.05).
For the cyanide content of the raw cassava, it was determined that Namunyongo had the
highest cyanide content of 82.39mg/kg, followed by Chila with 77.84mg/kg. Namunyongo,
Chila and Bangweulu were in the lethal cyanide dose of above 50 mg/kg that was stipulated
by ZABS (2008). The cyanide content for the three varieties (Bangweulu, Chila and Na-
munyongo) was still very high and above the safe cyanide level of 10 mg/kg stipulated by
ZABS (2008) even after processing while all the varieties were below.
5.2. RECOMMENDATIONS
The cyanide content for the flour was still very high for Namunyongo (29.98 mg/kg), Chila
(24.61 mg/kg) and Bangweulu (16.79 mg/kg). These values were above the safe cyanide
level of 10 mg/kg stipulated by ZABS (2008). Hence, this simply means that the processing
method that was employed was not effective in reducing the cyanide level to safe levels. It is
recommended that a method that is capable of reducing the cyanide levels to safe levels
should be used in order to make the flour for the mentioned varieties safe and edible. For
example, a method that makes use of graters instead of a manual cassava chipper can in-
crease cell disruption and hence, increase contact of linamarin with linamarase thereby set-
ting the hydrogen cyanide (HCN) free. Hydrogen cyanide (HCN) is known to volatize at tem-
peratures of 26 (Brimer et al, 2007).
With the current increasing demand for cassava starch in industrial use (Chitundu, 2009), it
is recommended that cassava producers as well as processors increase value addition of
cassava by following the right processing methods and use of suitable cassava varieties to
guarantee safe and quality products. This will in turn lead to improved food security and in-
creased household incomes which should translate into improved livelihoods. It is also rec-
ommended that this information presented in this research project be used to come up with
HQCF which should meet different industrial specifications.
It is also recommended that the starch content and its functional properties for each cassava
variety should be determined in order to evaluate and come up with appropriate usage for
each variety. The cassava varieties from each cassava belt should be compared in terms of
physico-chemical composition in order to determine which region produces cassava of high
quality.
Email: [email protected]; [email protected]
REFERENCES
1. Akintonwa A., Tunwashe O., and Tewe O., (2001), Utilization of Whole Cassava
Plant in the Diets of Growing Pigs in the Tropics, Livestock Research for rural devel-
opment.
2. Akanji A.O., (1994), Cassava Intake and Risk of Diabetes in Humans, Acta Hortic.
(Wageningen) 375, 349-359.
3. Allen A.C., (2002), The Origins and Taxonomy of Cassava, WallingFord/ New York.
USA.
4. Anon (1994), Summary and Recommendations, Proceedings of the International
Workshop on Cassava Safety, Ibadan, Nigeria, March 1-4, 1994. Acta Hortic. (Wa-
geningen) 375, 11-19.
5. Banea M., Poulter N.H., and Rosling H., (1992) Shortcuts in Cassava Processing and
Risk of Dietary Cyanide Exposure in Congo, Food and Nutrition Bulletin 14, 137-143.
6. Chitundu M., Droppelmann K., Haggblade S., (2006), Approach for Managing Pri-
vate-Public Partnerships, Zambia Task Force on Acceleration of Cassava Utilization,
Lusaka Zambia.
7. Chiona M., and Simwambana M., (2004), Cassava Production Guide, Root and Tu-
ber Improvement Programme, Mansa, Zambia.
8. Chiwona K. L., (2001) A Reason to be Bitter, Cassava Classification from the
Farmers Perspective, Stockholm- Sweden.
9. Dziedzoave N. T., Andrew G., and Boateng E. O., (2007), Training Manual for the
Production of High Quality Cassava Flour, Accra Ghana.
10. Encarta Encyclopaedia, (2009).
11. FAO (1989), Utilization of Tropical Foods, Roots and Tubers.
12. FAO (1988), Root and Tuber Crops, Plantains and Bananas in Developing countries.
13. Haggblade S., and Nyambe M., (2007), Structure and Dynamics of Zambias Cassa-
va Markets.
14. Leithner D.E., (1983) Management and Evaluation of Intercropping Systems with
Cassava, CTA CALI, Colombia.
15. Luhila F., (2000), Household Cassava Processing in Zambia, Programme Against
Malnutrition, Lusaka, Zambia.
16. MAFF, (2007), An Evaluation of the Commercial Potential for Cassava in Zambia,
Lusaka, Zambia.
17. Maria B., (2010), Production of Cassava- Based Bakery Products and Tropical Fruits-
Home Recipes, Brazil.
Email: [email protected]; [email protected]
18. Mling N., (1995), Cassava Processing and Dietary Cyanide Exposure in Tanzania,
Uppsala- Sweden.
19. Nweke I. F., Dunstan S.C., and Lynam J.K., (2002), The Cassava Transformation,
Africas Best Kept Secret, Michigan State University.
20. Onabolu A., Abbass A., and Bokanga M., (2003), New Food Products from Cassava,
Second Edition IITA, Ibadan, Nigeria.
21. Peterson S., Rosling H., Tylleskar T., Gebre M., and Taube A., (1995), Endemic Goi-
tre in Guinea, Lancet.
22. Sakala N., (2004), Evaluation of Rural Processing Techniques of Cassava for the
Reduction of Cyanides, Department of Food Science and Technology, University of
Zambia.
23. UNICEF IITS (1990), Cassava in Tropical Africa.
Email: [email protected]; [email protected]
APPENDIX 1
PHOTOS OF SELECTED SAMPLES
Mansa varieties
Email: [email protected]; [email protected]
Chongwe varieties
Kamuliboko Lipalumusi
Chipping Drier
Dried chips
Email: [email protected]; [email protected]
APPENDIX 2
RAW DATA
Table 1: Moisture determination on raw cassava (Mansa)
Variety Weight of
dish (g)
Weight of
sample
(g)
Weight of
dish +
dry sam-
ple (g)
Moisture %
Mean
moisture
%
Standard
deviation
Corrected
Moisture
%
Kampolombo
8.836 2.038 9.507 67.08
68.17 1.51 68.17
1.5 8.498 2.045 9.162 67.53
10.058 2.026 10.668 69.89
Chila
8.592 2.016 9.253 67.21
66.03 1.64 66.031.6 8.876 2.034 9.605 64.16
8.377 2.008 9.045 66.73
Tanganyika
8.933 2.023 9.538 70.09
66.76 2.89 66.763 8.647 2.021 9.355 64.98
8.391 2.036 9.099 65.23
Katobamputa
8.288 2.042 9.07 61.70
60.31 1.51 60.311.5 7.226 2.016 8.022 60.52
8.39 2.034 9.23 58.70
Namunyongo
7.788 2.006 8.538 62.61
61.25 1.19 61.251.2 7.268 2.025 8.068 60.49
7.655 2.06 8.466 60.63
6.015 2.05 6.965 53.66
60.83 6.62 60.836.6 Kariba 6.02 2.003 6.687 66.70
3.401 2.025 4.168 62.12
Nalumino
7.646 2.05 8.629 52.05
50.68 3.18 50.683.1 8.803 2.023 9.755 52.94
7.546 2.047 8.63 47.04
Bangweulu
7.63 2.01 8.36 63.68
61.74 3.12 61.743.1 8.672 2.033 9.523 58.14
8.479 2.038 9.225 63.40
Kapumba
3.365 2.02 4.255 55.94
57.08 0.99 57.081 8.722 2.025 9.578 57.73
8.48 2.037 9.344 57.58
Email: [email protected]; [email protected]
7.901 2.012 8.733 58.65
58.20 0.79 58.200.8 Mweru 8.83 2.037 9.672 58.66
7.404 2.044 8.277 57.29
Email: [email protected]; [email protected]
Table 2: Moisture content on the flour (Mansa)
Variety Weight of
dish (g)
Weight of
sample
(g)
Weight of
dish +
dry sam-
ple (g)
Moisture %
Mean
moisture
content
%
Standard
deviation
Corrected
Moisture %
Kampolombo
8.378 2.031 10.242 8.22
7.43 0.85 7.430.85 7.653 2.042 9.541 7.54
8.288 2.035 10.19 6.54
Chila
8.828 2.002 10.662 8.39
8.43 0.23 8.430.23 8.469 2.018 10.321 8.23
10.097 2.016 11.938 8.68
Tanganyika
7.633 2.007 9.488 7.57
7.38 0.83 7.380.83 7.225 2.025 9.119 6.47
8.803 2.012 10.652 8.10
Katobamputa
7.787 2.031 9.659 7.83
7.55 7.550.24 7.646 2.045 9.539 7.43 0.24
8.931 2.03 10.811 7.39
Namunyongo
7.267 2.03 9.105 9.46
8.25 1.16 8.251.16 8.479 2.026 10.36 7.16
8.876 2.043 10.753 8.13
Kariba
3.364 2.016 5.255 6.20
5.27 1.40 5.271.4 8.391 2.045 10.361 3.67
8.721 2.015 10.616 6.00
Nalumino
7.899 2.048 9.829 5.76
6.09 0.74 6.090.74 8.497 2.003 10.361 6.94
6.02 2.01 7.918 5.57
Bangweulu
8.831 2.033 10.762 5.02
4.66 0.70 4.660.7 7.404 2.038 9.338 5.10
8.641 2.022 10.585 3.86
Kapumba
10.566 2.005 12.432 6.93
6.30 0.75 6.300.75 8.591 2.028 10.508 5.47
10.589 2.016 12.474 6.50
Mweru
8.389 2.018 10.328 3.91
3.93 0.45 3.930.45 8.672 2.008 10.61 3.49
3.399 2.026 5.336 4.39
Email: [email protected]; [email protected]
Email: [email protected]; [email protected]
Table 3: Moisture content on the flour (Chongwe)
Variety Weight of
dish (g)
Weight of
sample(g)
Weight of
dish +
dried
sample
Moisture %
Mean
Moisture
%
Standard
deviation
Corrected
Moisture
%
Linangwa 10.414 2.042 12.316 6.86
6.73 0.18 6.70.18 3.399 2.058 5.321 6.61
Nakamoya 10.565 2.088 12.504 7.14
6.79 0.49 6.80.5 7.48 2.003 9.354 6.44
Nalumino 10.417 2.03 12.312 6.65
6.82 0.2