Characterisation of Cassava Varieties for Appropriate Utilisation

download Characterisation of Cassava Varieties for Appropriate Utilisation

of 87

description

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

Transcript of Characterisation of Cassava Varieties for Appropriate Utilisation

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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.

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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.

  • Email: [email protected]; [email protected]

    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.

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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)

  • Email: [email protected]; [email protected]

    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.

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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.

  • Email: [email protected]; [email protected]

    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

  • Email: [email protected]; [email protected]

    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