Thesis Abstract

Abstract
The aim of this study was to investigate the effect of storage time on the functional properties of a wheat-bambara groundnut blend. The blend was prepared in the ratio of 7030 (wheatbambara groundnut) and stored under ambient conditions for a period of 90 days. The functional properties evaluated included water absorption capacity, oil absorption capacity, emulsifying capacity, foaming capacity, and bulk density. Results showed that water absorption capacity increased significantly during the first 30 days of storage and then remained relatively stable until the end of the storage period. Oil absorption capacity also increased over time, with a significant increase observed after 60 days of storage. Emulsifying capacity and foaming capacity both showed a decreasing trend during the storage period. Bulk density of the blend increased steadily throughout the storage period. Overall, the functional properties of the wheat-bambara groundnut blend were affected by storage time, with changes observed in water absorption capacity, oil absorption capacity, emulsifying capacity, foaming capacity, and bulk density. These findings suggest that storage time can have a notable impact on the functional properties of blended flours, which should be taken into consideration in food processing and product development.

Thesis Overview

1.0 INTRODUCTION
1.1 WHEAT (TRITICUM AESTIVUM)
1.1.1 ORIGIN AND DISTRIBUTION
Despite many years of investigation, it has not been possible to determine accurately when and where the first cultivated wheat originated. At the beginning of recorded history, wheat was already an established crop whose origin was unknown (Anon 1953). There is however some evidence that cultivation of wheat started about 6,000 years ago in the 5yria – Palestine area and spread to Egypt, (ran, India, China, Russia, Turkey and Central Europe from where it spread to other countries and continents. Countries that produce wheat today include Russia, Switzer land United State of America, Belgium, Canada, Denmark, England, Poland, Netherlands, Norway, Swedan, South Africa, Peru, Australia, Argentina, Chile, Newzealand and Nigeria. 9Shellenberger, 1969, Olugbemi etal 1992).
In addition, wheat flour has uniques properties that differs it from other flours in containing a considerable proportion of gluten which makes wheat flour suitable for bread making and other bake products. This composition of gluten present has a bearing on the “strength” and water holding properties of the flour. The two protein that form the greater part of the guten are gluternin and gliadin while the latter appear to be identical in strong and weak wheat, the former exists in different varieties.

1.1.2 STRUCTURE OF WHEAT KERNEL
The main feature of the wheat kernel can be best described in terms of the rounded or dorsal side and a vertical or crease side (Shellenberger, 1969). A deep groove a crease extends the entire length of the wheat kernel. At the apex or the small end of the grain there are many short fine hairs called brush hairs. The outer bran or seed coat consist of three layers known as epidermis.
Wheat grain has the following average percentage composition. Endosperm 85% of the whole grain from which the flour is derived bran 12.5%, germ 2.5%. the composition of wheat flour however varies considerably according to the class of wheat, its country of origin, proportion of the outer part removed by the particular milling process (Ehias, 1972, Nelson 1985). The outer partcontain more protein, fat fibre and ash then the starchy endosperm. The proportion of each of these constituents decreases as the extraction percentage gets less.

1.2 CULTIVATION OF BAMBARA GROUNDNUT
It is mostly monocropping in a selected plot of land with suitable sandy soil 82% of households in North central are 67% in kavango planted Bambara groundnut in 1993. Estimating an average of 1400m2 per farm cropped with Bambara groundnut, the total production areas sums up to around 3000ha. Production figure are very variable, depending on the rainy season. Due to wide spacing 10 – 12 plants/m2 and lack of improved varieties yield rarely exceed 500kg/ha. Taking 250kg/ha as an overall average of the total production to 750t/year.
This does not satisfy the market requirements and a considerable amount of Bambara groundnut is informally imported from Angola and sold with local materials on tradition markets. Seed size is an important factor for the marketing of Bambara groundnut.

1.1.3 USES
1. The dried mature seed cab be converted into paste, steamed and eaten with vegetable soup or sauce.
2. The form in which the Bambara groundnut seed is commonly consumed is moin-moin usually referred to as ‘Okpa’ in the eastern states of Nigeria.
3. Dried and roasted Bambara groundnut can be used to make soup, flour and porridge.

1.1.4 USES OF WHEAT AND WHEAT PRODUCTS
1. Wheat is perhaps the most popular cereal grain for the production of bread, cake and other pastries in baking industries.
2. Wheat bran is used mainly for the formulation animal feed.
3. Farinha, shorts, semolina, semovita, flour from wheat are used for other preparation purpose.
4. It can also be used as an ingredient in breakfast, cereal, macaroni, adhesives and other products.

1.2 BAMBARA GROUNDNUT (VOANDZEIA SUBTERAEA)
1.2.1 ORIGIN
Bambara groundnut belongs to the family of flowering plant called leguminosease. It is an important legume consumed in Nigeria especially in Enugu State and some other Northern States. The Bambara groundnut is native to West Africa. Some wild species are found in North Eastern Nigeria and Northern Cameroon. It has different name’s in different parts of Africa. It is called ‘Okpa by the Igbos. Bambara groundnut is an important article of commerce in Nigeria. It grows extensively in Northern Nigeria but eaten mostly in eastern Nigeria. A large volume of trade is undertaken between the growing and the consuming population.
Bambara groundnut seed vary in shape, size and colour of the seed coat (Ojimelumelukwe (1985) differentiated between four cultivars with respect to the seed coast, colour and size. Seed may be round cream or russet brown smooth taste. The seeds have white elliptical helium with seed eight ranging between 280 and 320g.