ABSTRACT

The most logical approach towards the improvement and efficient use of indigenous seed to supply nutritional requirement for human diet is through the investigation of their nutritional values. This study was carried out to investigate the nutritional values and mineral content of locust bean (Parkia biglobosa) seed. The seed was separated from the fruit into outer yellow pulp and inner seed and were analyzed for proximate, vitamins and mineral contents. The result obtained from the proximate analysis of the flour of locust bean seed shows that the mechanical energy content of the Locust bean seeds was 395.76±0.28 which is higher than the Crude Protein content 43.82±0.56, followed by the Lipids content 24.48±0.21, Crude Fibre content 21.38±0.14. The moisture content of Locust bean seeds was 7.84±0.07 which is lower than mechanical energy, crude protein, crude fibre, lipids but higher than the Ash and Nitrogen free extracts (NFE) which has the content of 2.44±0.12 and 0.06±0.03 respectively. The result obtained from the mineral composition of the flour of locust bean seeds shows that the calcium content of the Locust Bean Seeds was statistically higher at p<0.05 having value of 0.68±0.08 than the Phosphorus content having a value of 0.09±0.05. This finding means that Locust bean seeds flour can serve as good source of plant protein in human nutrition. It can also provide an alternative way of using the human nutrition cereals to improve global food security challenge.

TABLE OF CONTENTS

CHAPTER ONE

INTRODUCTION

1.1       Background of the Study     –           –           –           –           –           –           1

1.2       Statement of the Problem     –           –           –           –           –           –           3

1.3       Purpose of the Study –           –           –           –           –           –           –           4

1.4       Research Questions   –           –           –           –           –           –           –           4

1.5       Research Hypotheses            –           –           –           –           –           –           4

1.6       Significance of the study      –           –           –           –           –           –           4

1.7       Scope and Delimitation of the Study           –           –           –           –           5

1.8       Operational Definition of Terms     –           –           –           –           –           5

CHAPTER TWO

REVIEW OF LITERATURE

CHAPTER THREE

MATERIALS AND METHODS

3.1       Study Area     –                       –           –           –           –           –           –           25

3.2       Research Design                    –           –           –           –           –           –           26

3.3       MATERIALS/REAGENTS USED FOR THE STUDY   –           –           26

3.3.1    Materials        –           –           –           –           –           –           –           –           26

3.3.2    Reagents and Chemicals       –           –           –           –           –           –           27

3.3.3    Study Object  –           –           –           –           –           –           –           –           27

3.4       METHODS   –           –           –           –           –           –           –           –           27

3.4.1    Sample Collection     –           –           –           –           –           –           –           27

3.4.2Locus Bean Seed Processing    –           –           –           –           –           –           28

3.5       PROCEDURES OF THE NUTRITIONAL

AND MINERAL CONTENT ANALYSIS –          –           –           28

3.5.1    Procedures for moisture analysis (AOAC, 2003)   –           –           –           28

3.5.2    Procedure for Crude Ash Analysis (AOAC, 2003)            –           –           30

3.5.3    Procedure for Crude Protein Analysis (Kjeldahl Method)          –           30

• Procedure for Crude Fat (Soxlet Method) – –           –           –           32
• Procedures for Crude Fibre

Analysis – (Filtration Method)        –           –           –           –           –           33

3.5.6    Procedure for Calcium

Analysis – (Spectrophotometric Method)   –           –           –           –           35

3.5.7    Procedures for Phosphorus

Analysis – (Spectrophotometric Method)   –           –           –           –           36

3.6      DATA ANALYSIS               –           –           –           –           –           –           38

CHAPTER FOUR

RESULTS AND DISCUSSION

4.1       Proximate Analysis of the Flour of

Locust Bean Seed      –                       –           –           –           –           –           39

4.2       Mineral Composition of the Flour of         

Locust Bean Seeds    –           –           –           –           –           –           –           41

4.3       Discussions     –           –           –           –           –           –           –           –           43

CHAPTER FIVE

SUMMARY OF FINDINGS, CONCLUSION, RECOMMENDATION, LIMITATION AND SUGGESTION FOR FURTHER STUDY

5.1       Summary of Findings           –           –           –           –           –           –           46

5.2       Conclusion     –           –           –           –           –           –           –           –           47

• Recommendation      –           –           –           –           –           –           –           47

5.4       Limitation of the Study        –           –           –           –           –           –           48

5.5       Suggestion for Further Study          –           –           –           –           –           48

REFERENCE           –           –           –           –           –           –           –           49

APPENDIX   –           –           –           –           –           –           –           –           56

CHAPTER ONE

INTRODUCTION

1.1       BACKGROUND OF THE STUDY

Cowpea is a popular leguminous crop in Africa which is known as beans in Nigeria and ‘niebe’ in the Francophone countries. The largest production is in the moist and dry savannah of sub-saharan Africa (SSA) where it is intensively grown as an intercrop with other cereal crops like millet, sorghum and maize as well as rice fallows (Ishiyaku et al., 2010). Though it is grown in other parts of the world, Nigeria remains the largest producer and consumer of cowpea in the world. According to Food and Agriculture Organization (FAO) data (2001-2010), Nigeria produces an average of 2.58±0.31 million metric tones. Demand deficeit is met by Niger and Burkina Faso.

The wild cowpea species (Var pubescens) belongs to vigna unguiculata subsp. Dekindtiana var. dekindtiana and almost have growth habit and leaf shape to local cowpea varieties grown by farmers, except the pod shape in the wild type which is tiny, black at maturity and held in upright position with faint leaf marks (Padulosi, 1990). The perennial wild vigna unguiculata has 2.5m long creeping stems, distinctive hair, large stipules and deep purple flowers. The wild type is typical to vigna unguiculata subsp. Dekindtiana var. pubescens. It also has long and narrow leaves, similar to those of vigna unguiculata subsp. Stenophylla, available in southern Africa. The wild cowpea V. unguiculata var spontanea is not for human consumption neither for animal’s feeds but present diet that can be analyze to determine its toxicity level. In Malalani for example, an area of wild population in coastal Kenya, after each mechanical clearing of the roadsides, the wild population of Cowpea increased. A research by Organization for Economic Cooperation and Development (OECD) working group (2015) states that during annual seed supplementation trial in Muhaka field station, Kenya, the ploughed plots had wild cowpea plants more than the undisturbed plots (OECD working group, 2015 cited R.S. Pasquet, personal communication). The wild cowpeas are available in natural ecosystems from eastern Cameroon, Uganda, and western Ethiopian lowlands and found only in disturbed places (fields, field margins, roadsides and fallows). Others include Burkina Faso, western Niger and northern Ghana, West Africa (Nigeria). Wild cowpea and its relatives are not for addressing significant weed problem in sub – Saharan Africa (OECD working group, 2015 cited Huesing et al., 2011). The cultivated cowpea and wild type, locally known as “Waken Gizo” are both in the same genus, vigna, species unguiculata and subsp Dekindtiana. They differ from each other only in variety. The wild type is var. pubescen while the cultivated cowpea derived from var. Dekindtiana (Padulosi and Ng, 1990).

Markoni et al., (1990) in their research observed that wild cowpea species had higher protein content but lower protein digestibility, while cowpea varieties had lower protein content but higher protein digestibility. Nevertheless, the available protein in wild species was slightly higher than that of the cultivated species. The differences in digestibility may be attributed either to factors that are intrinsic to the protein themselves or to other substances present such as tannins, phytates, fibre or protease inhibitors, that may interact with proteins (Markoni et al., 1990). Wild species are having higher inhibitors than cultivated cowpea (Carnovale, 1990).

The determination of elemental nutrient profile of wild cowpea (Var. pubescens) grain is a good way in order to stretch its edible nutrient and to create awareness to its toxicity characterization. It is therefore important and will contribute to alleviating nutritional deficiency in Nigeria. It is believed that improving cowpea for nutritional value will greatly improve the diets of people affected by hunger and malnutrition. It is upon this background that the research deems it fit to investigate into the elemental nutrient profile of a wild cowpea (Var. pubescens) grain for nutritional studies.

1.2       STATEMENT OF THE PROBLEM

Recently the urgency of the world food problem has thrown a challenge not only to the agriculturist and nutritionist but also to the foresters, to investigate the possibility of utilizing product from wild plants as additional source of protein, fat, vitamins, minerals and energy. In order to guide the choice of the portion of wild crops (wild cowpea species) to be consumed and the provenance that will be very rich in term of their nutritional value, there is the need to chemically analyze the nutritional composition of the wild cowpea (Var pubescens). Hence this study was designed to determine the elemental nutrient profile of a wild cowpea (Var pubescens) grain for nutritional studies.

Over the years, there is evidence that many rural dwellers/inhabitants who cannot afford animal products and crops of highly protein sources such as cowpea which are rich sources of protein because they are either too expensive or simply unavailable which has lead to highly dependence on carbohydrate sources. The increasing reliance on carbohydrate sources is as a result of lack of awareness, creative skills as well as technical skills by the agriculturists, nutritionist and farmers to effectively utilize leguminous crops through chemically analysis and determination of the nutritional composition of these wild crops (wild cowpea) to come up with less expensive protein sources. It is upon this background that the researcher deems it fit to determine the elemental nutrient profile of a wild cowpea (Var pubescen)s grain for nutritional studies in breeding programmes.

1.3       PURPOSE OF THE STUDY

The general aim and objectives of this study is to determine the elemental nutrient profile of a wild cowpea (Var. pubescens) grain for nutritional studies in breeding science. Specifically, the study seeks to:

1. Analyze the nutritional values of wild cowpea grain.
2. Determine the elemental content of wild cowpea grain.
3. Evaluate the health benefit of wild cowpea to mankind.

1.4       RESEARCH QUESTIONS

The following research questions guided the conduct of this study;

1. What are the nutritional values of wild cowpea grain?
2. What is significant elemental content of wild cowpea grain?
3. What is the health benefit of wild cowpea to mankind?

1.5       RESEARCH HYPOTHESES

The following null hypothesis guided the conduct of this study;

1. There is no significant nutritional value in wild cowpea grain
2. There is no significant elemental content in wild cowpea grain.
3. The nutritional values and mineral content of wild cowpea has no effect on human health.

1.6       SIGNIFICANCE OF THE STUDY

            This study will be of immense importance to nutritionist, agriculturist, foresters, food science research institutes by creating awareness and technical skills to effectively utilize product from wild plants as additional source of protein, fat, vitamins, minerals and energy to be consumed and the provenance that will be very rich in term of their nutritional value as well as to get acquaintance with their toxicity characteristics and its impact on human health.

            The findings of this study will help solve food insecurity by providing to the masses harnessed leguminous wild crops such as cowpea as protein source to substitute high demands for animals protein sources.

1.7       SCOPE AND DELIMITATION OF THE STUDY

This research is delimited to the determination of the elemental nutrient profile of a wild cowpea (Var. pubescens) grain for nutritional studies.

1.8       OPERATIONAL DEFINITION OF TERMS

Terms that are related to the study are defined below in order to remove somatic ambiguity in their usage.

Determination:                                  It simply refers to a firm or fixed intention to achieve a desired end. In this study, it refers to the researcher’s intention and desired to effectively analyze the nutrient profile of wild cowpea grain in further supporting nutritional studies.

Elemental nutrient profile of cowpea: It is an effort to critically asses an essential nutrient element in cowpea which is required for the normal life cycle of an organism and where functions cannot be substituted by any other chemical compound.

Nutritional Value:                             It refers to the measure of a well-balanced ratio of the essential nutrients carbohydrates, fat, protein, minerals, and vitamins in items of food or diet concerning the nutrient requirements of their consumer.

Mineral Content:                  Literally, it implies those elements on the earth and in foods that our bodies need to develop and function normally. In this study, it refers to examination of those minerals present in wild cowpea  species that are essential for human health and they may include calcium, phosphorus, potassium, sodium, chloride, magnesium, iron, zinc, iodine, chromium, copper, fluoride, molybdenum, manganese, and selenium.

Wild Cowpea:                                    Is a plant of the pea family native to the Old World tropics. It possesses toxicity characterization that needs to be analyzed.