Description
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Starch can be obtained from cassava, sorghum, maize, and potatoes. But this project focuses on the production of starch; from cassava. Starch can be cross-linked, a product that is suitable for noodles, salad cream, custard making. Normally, it is easier to make this product from corm and potato, but cassava which is readily available and cheap can be employ to meet the demand of the people.
Cassava is a single species, manihot esculent crantz (Synonyms with mainhot utilissmapole). It is a tuberous dicotyledous plant, belonging to the botanical family. The cassava plant contains latifiers and product latex. The cassava tubers contain mainly water and carbohydrate with water having a greater proportion and a small significant amount of cyanogenic glycoside (Prussic acid) of all constituents of cassava tubers. It is an important food crop in tropical countries such as Brazil, Nigeria, Indonesia and Thailand. The roots of the cassava are rich in starch and are consumed as human food or animal feed.
Cassava (Mainhot esclenta crantz) is a major food crop in Nigeria. Supplying about 70% of it daily alone of over 50 million people in Nigeria. It is the most important crop in term of population and has also been estimated that cassava provides food for over 500 million people in the world.
The consumption of cassava has currently been on the increase and Nigeria has the largest cassava producer in the world since 1989.
Fig. 1 Cassava
1.1.2 ORIGIN, TYPES AND COMPOSITION OF CASSAVA STARCH
Cassava is a staple crop that is particularly important in South America, America and African countries. It is a perennial shrub that grows to approximately 2 meters tall and has the ability to grow on a marginal land in low nutrient soil where other crops do not grow well. It is also fairly drought tolerant. It is grown for its enlarged starch rich tuberous roots.
Although cassava is a staple crop, it is poisonous in it raw state as the plant contains Cyanogenic Glucoside. These Glucosides are converted to HCN by enzymes called Linamanase which is present in cassava and acts on the glucosides when the plant cell are ruptured during consumption stage.
The amount of cyanide contain in cassava depends on the variety and stage of the cassava. There are two types of cassava.
Bitter cassava (Manihot Utilissiana)
Sweet cassava (Manihot Patinate)
The cassava (Manihot esculent a Crantz) is cultivated mainly in the tropic and sub-tropic regions of the world, over a wide range of environmental and soil conditions. It is tolerant of insect pests and diseases, and it very tolerant of drought and Heat Street.
In many cassavas does not a labour intensive crop and produces well on the marginal soil. In many of the cassava growing regions of the world, however, the cassava does not achieve its yield potential, due primarily to disease and limited inputs such as fertilizer and irrigation (Siritunga and Sayre, 2004).Estimates of the food and agriculture organization of the United Nations (FAOSTAT, 2011) put world production of cassava at more than 230million metric tones annually. Major producers of cassava include Nigeria (37.5 million tones per annum), brazil (24.5 million tones) and Thailand (22.0 million tones). For the Caribbean region, annual production is in excess of 1.2 million tonnes, with the bahamus contributing about 240 tonnes to this figure.
The cassava is an important component in the diet of more than 800 million people around the world (FAO, 2007) and is the third largest carbohydrate food source within the topical regions, after rice and corn (Ceballos et al. 2004). Cassava is referred to as a food security crop (Barratt et al. 2006), which can be left in the ground of extended periods of up to two years, until required. It is used mainly as a fresh food item, but it also processed into various food and non-food products, such as starch, flour, beverage, animal feeds, biofuels and textiles.
There is much variation in the nutrient quality of the cassava root (Chaves at al., 2005). In the tropical regions, cassava is the most important root crop and, as a source of energy, the calorific value of cassava is high, compared to most starchy crop (Okigbo, 1980).
The starch content of the fresh cassava root is about 30%, and gives the highest yield of starch per unit area of any crop known (Tonukari, 2004). The protein content is extremely low, however, and ranges between 1-3% (Buitrago, 1990; Salcedo et al, 2010). The cassava root contain a number of mineral elements, in a appreciable amounts, that Are useful in the human diet The root contains significant amounts of iron, phosphorus and calcium, and is relatively rich in vitamin (Enid Iola et al., 2008).
There are several thousand varieties of cassava and about 100 related wild species (Hershey et al., 1997), with hydrogen cyanide (HCN) contents of their roots ranging from 1-1550 parts per million (PPM) (Cardoso et al., 2005). Cassava plants are generally categorized as bitter or sweet, depending upon their cyanide content. The low-HCN, or sweet cassava, has less than 50ppm of gynogenic equivalents, while the high-HCN, or bitter cassava has more than 100ppm (Wilson and Dufor, 2002). According to Adepoju et al., (2010), the food value of cassava is greatly compromised by its toxic hydrogen cyanide content. The sweet cassava can be cooked and eaten as they are, while the bitters cassava needs to be processed before being consumed.
A large amount of variation exists among the cassava leaf, stem and root characteristics, which include leaf morphology stem colour, branching habit and storage root shape and colour, may influence cassava yield (Ntawurunhunga and Dixon, 2010). Other, not so obvious, characteristics include resistance to insect pests and diseases. A proper understanding of these variations in plant characteristics would assist the selection of cassava types with the desired traits. This, in turn, will contribute to improved crop establishment and increased yields.
Among the objectives of the root and tuber crops programme at the Gladstone road agriculture Centre are to identify high yielding cassava varieties, to evaluate and preserve cassava germplasm and to provide good quality planting material for local farmers. However, very little documented information on the performance of cassava on the calcareous soils of the Bahamus, under improved agronomic practices, is available. With this present study, efforts are being made to evaluate existing varieties and new introductions for their yield potential under local conditions. Cassava production in the Bahamas could be improved through the introduction of improved varieties and the adoption of improved agronomic practices.
1.2 AIMS OF THE STUDY
To produce cassava starch and to study the chemical functionality and pasting properties which would form a basis of processing for the development into edible form.
It is also aimed at investigating proximate analysis of produce cassava starch.
1.3 OBJECTIVE OF THE STUDY
The objective of this project is based on the production of starch from cassava, using a manual instrument called grater to open all the tuber cell, so that the starch granules are easily release and extract through hydraulic press or sieve, and to evaluate the nutritional composition present in the three varieties of the cassava starch.
1.4 SCOPE OF THE STUDY
The scope of this project is on the following analysis, production of edible starch, ash content of the cassava starch, moisture content of the cassava starch. At the end of this work, the results of all analysis were shown.
1.5 LIMITATION OF THE STUDY
The limitation of this project work is based on the toxic substances found in cassava root which is Cyanogenic glycosides. The level depends on the genotypes well as environmental factors, for instance brought. Acute poisoning and death following consumption of cassava is rare.