ABSTRACT

Afzelia africana seeds (African Oak) were processed into flour using three different treatments. The treatments include: rawAfzelia Africana flour (sample A) the control. The seeds were cracked and dehulled. The boiling method, the seeds were boiled for 20 mins at 1000C (sample B) and soaking method, the seeds were soaked for 5 days (sample C), both were dehulled sundried,milled and seived using 60mm mesh. Then sample D was a combination of akpalata flour of boiled and soaked in a ratio of 50:50. Proximate coposition and functional properties were carried out. The following results were obtained from proximate analysis of flour sample A, B, C, and D moisture content 10.96%, 10.51%, 10.71%, and 10.23%, Ash 3.38%, 3.25%, 3.43%, and 3.37%, fat 11.64%, 10.18%, 11.48%, and 11.26%, protein 17.76%, 17.02%, 17.59% and 17.25%, carbohydrate 56.26%, 59.04%, 56.79% and 57.89%. The results of functional properties of sample A,B,C and D were obtained as these gelation capacity 0.97%, 0.83%, 0.77%, and 0.6%, Bulk density 3.09%, 3,32%, 3.03% and 3.08%, water absorption capacity 450%, 470%, 463%, 453%, oil absorption  capacity 400%, 355%, 336% and 367%, viscosity maximum 100%, 102.5%, 103.3%, 108.4% for sample A,B,C, ad D. From the results above, both samples could serve as soup thickener, but sample A has highest moisture, protein and fat content showing that temperature affects proximate composition of African Oak seeds.

CHAPTER ONE

INTRODUCTION

Grain legumes are major sources of dietary protein in the developing countries, as animal proteins are expensive. In addition to the protein contribution legumes are rich in other nutrients such as starch, dietary fibre, protective phytochemical, oil, vitamins and minerals elements.

Legumes contain about 60% carbohydrate including starch, reducing and non-reducing sugars, oligosaccharides of the raffinose family etc.

Afzelia africana is a leguminous tree plant that belong to the family of fabaccae. Afzelia africana is known as Akpalata in eastern part of Nigeria, Kawo in North and Apa in west. It is a large tree with very beautiful coloured seeds having two colour black and yellow/orange at the

bottom, that looks like a cap with extractable oil. The seeds are edible and have high medicinal values. All parts of the plant are of immense traditional importance, its wood is used for carpentry, the saw dust for making and designing art work, its foliage for making soap, while the leaves are used to enrich soil because of their rich nitrogen content (Achard, 1980).

Afzelia africana is evergreen small to fairly large tree, commonly up to 15m tall, but sometimes in damper localities up to 30m. Bole of girth to 3m, buttressed and seldom over 16m long of Soudanian savanna and fringing forest form casamance Senegal to south Nigeria and across central Africa to Uganda.

Afzelia africana is a deciduous plant that bears 6-10hard shiny seed in a pod, it is ellipsoidal in shape. It is a plant with paripinnate leaves, the leaves are arranged opposite one another, they have entire margin.

Afzelia africana is found on a wide variety of soil types, often on hand pans soil on steep slopes, as well as a depression and in regularly inundated sites.

Afzelia africana shows a wide adaptation to climatological condition but is most common in area with an annual rain fall of more than 900mm.

Afzelia africana is a good emulsifying agent, when the seed is roasted, it develops a very pleasant and strong aroma which makes it very unique among other tropical legume soup thickeners such as Mucuna flagellipes“Ukpor” and Detearium micocarpuma “offor” which are bland and coloured.

The seed of Afzelia africana also contain oil which range from 18 – 37% the oil contained beta carotene, plant sterols, phospholipids and glycolipids.

Toxicological studies show absence of gossypol and no detectable mycotoxins.

As a matter of fact, the limitation in the use of  many legumes in food system is that they contain anti-nutritional factors some of which are flatulence factors and trypin inhibitors. Though Afzelia africana has not been extensively studied, there are no reported disorders of flatulence or any other digestive cases arising from its consumption once it is properly processed.

Afzelia africana is considered a fetish tree in many regions, the roots, bark, leaves, and fruits are used in traditional medicine.

Though the flour from this legumes has been in use as emulsifier and soup thickener it has received little attention and recognition from researchers unlike some edible legumes such as soybeans, groundnut, and bambara nut.

In order to increase the Afzelia africana production and utilization, one of the approaches will be to expose its major components to processing. The functional characteristics need to be evaluated as has been done for other legumes.

OBJECTIVES OF THE STUDY

The aim of this work is to evaluate the following physiochemical as well as the

1)          Production of Afzelia africana flour using different processing methods.

2)          To determine the proximate composition of Afzelia africana.

3)          To determine the functional properties of Afzelia Africana.