Influence Of Processing Methods On The Protein And Cyanide Content Of African Yam Bean Sphenostylis Stenocarpa
The influence of processing methods on the protein and cyanide content of African yam bean (Sphenostylis stenocarpa) is a pivotal aspect of food science research, particularly in regions where this legume is a dietary staple. Various processing techniques such as soaking, boiling, and fermentation play a significant role in altering the nutritional composition of African yam bean, impacting its protein content and cyanide levels. These methods contribute to the enhancement of protein digestibility and bioavailability while concurrently reducing cyanogenic glycosides, thus improving the safety and nutritional value of the legume. Understanding the effects of processing methods on the protein and cyanide content of African yam bean is crucial for optimizing its nutritional benefits and promoting its consumption in diverse culinary contexts, thereby addressing food security challenges and fostering sustainable agricultural practices in Africa.
Raw African Yam bean (Sphenostylis stenocarpa) was subjected to various processing methods Viz: steeping in water for 6 hr and then boiling for 10, 20, 30, minutes respectively (samples B); steeping in water for 12 hours and then boiling for 10, 20, 30, minutes respectively (sample C) and finally sample A was raw yam bean which served as control. The entire sample was dry – milled into fine flours. The glycosidic cyanide, crude protein, ash, moisture, some functional properties and bulk density of the flours were analyzed from the results, protein and cyanide content of sample A (raw sample) are 25.20% and 72.23ml. results showed that the toasting, process gave the highest protein (24.12) with no trace of cyanide and it negatively affected the protein content of the samples reducing it from 25.20 to 17.57, 17.51(%) respectively. 12 hours soaking and few minutes boiling process negatively affected the protein content of the samples reducing it from 25.20% to 13.12, 12.78, 12.09 (%) respectively but have the strongest impact in covering the cyanide level from 72.23ml to zero respectively. Moisture content ranges from 400% – 14%, Ash ranges from 2.50% to 5.00%, water absorption ranges from 105g/ml to 290g/ml, oil absorption ranges form 0.98 – 1.95g/m. The bulk density showed 0.74g/ml – 0.88g/ml.
Title Page
Approval Page
Dedication
Acknowledgement
Table Of Contents
Abstract
Chapter One
1.0 Introduction
Chapter Two
2.0 Literature Review
2.1 Legumes
2.2 Nutritive Value Of Legumes
2.3 African Yam Bean
2.4 Utilization Of African Yam Bean
2.5.0 Limitations In The Utilization Of African Yam Bean
2.5.1 Unacceptable Flavour
2.5.2 Hard – To – Cook Phenomenon
2.5.3 The Presence Of Anti – Nutritional Factors
2.4.1 Pre – Conditioning Treatment Used In African Yam Bean Processing
2.7.0 Functionality Of Legume Protein/Flour
2.7.1 Nitrogen Solubility
2.7.2 Water And Oil Absorption
2.7.3 Emulsion Capacity
2.7.4 Foam Capacity
2.7.5 Gelation
Chapter Three
3.0 Materials And Source
3.1 Sample Preparation
3.2 Flow Charts For The Production Of The Different Flour Samples
3.2.1 Flow Chart For The Production Of Sample A (Raw Sample)
3.2.2 Flow Chart For The Production Of Samples B
3.2.3 Flow Chart For The Production Of Samples C
3.2.4 Flow Chart For The Production Of Toasted Sample (D Sample)
3.3.0 Determination Of Functional Properties Of African Yambean Flour
3.3.1 Water Absorption Capacity
3.3.2 Oil Absorption Capacity
3.4.0 Chemical Composition Of African Yam Bean
3.4.1 Determination Of Moisture Content
3.4.2 Determination Of Ash Content
3.4.3 Determination Of Crude Protein Content
3.5 Determination Of Glycosidic Cyanide
3.6 Determination Of Bulk Density
Chapter Four
4.0 Results / Discussion
Chapter Five
5.0 Conclusion
5.1 Recommendation
References
INTRODUCTION
African yam bean (Sphenostylis stenocarpa) belongs to the genera papilliona sec which is in the class known as Leguminousae (Okigbo, 1973). It is one of the neglected indigenous grain legumes in Nigeria. It is produced mostly in the eastern part of the country where it is consumed in different forms such as snacks, delicacy, man meal etc. It can be used for the fortification of other foods (Eke, 1997)
In Nigeria, it has as many names as there are communities cultivating it. Some of the names are Okpdudu, Azam, Uzuaku, Ijiriji, Azara, Ahaja, Nzamiri, Odudu, Girigiri (Hausa), sese (Yoruba) and Nsana (Ibibio) (Ogbo, 2002).
The high protein content of African yam bean makes it an important source of protein in the diets of population groups of many tropical countries (Kon, 1979, Ekpen young and Borchers, 1980). In addition, the high protein bean flour fractions could be substituted for wheat flour to produce acceptable qualities of cookies breads and leavened doughs (Uebersax and Zabik, 1986; Nzereogu, 1993).
It may also be consumed as porridge after cooking. The mature dry seeds can be used to prepare “moi – moi” and “akara” (Ezueh, 1973; Akoma, 1996). The African yam bean apart from being rich in protein also contains carbohydrate, fat and minerals (NAS, 1979).
A major constraint in the utilization of African yam bean is the different dehulling method. Traditionally, the dehulling method involves manual removal of the hulls from the individual soaked seeds. This method is quite laborous (labour intensive), time – consuming and does not favour effective utilization of the bean. It is widely believed that under cooked African yam bean seeds cause diarrhoea and over cooked seeds cause constipation (Asusu and Undie, 1986).
Previous works showed that steeping will among other things improve the dehulling characteristic of the African yam bean while maintaining the nutritional quality viz: invitro protein digestibility and also improving the functional properties when processed into flour (Abbey and Berezi, 1988). It is evident that better processing methods will not only enhance the acceptability and utilization of this legume but will also improve the nutritional status of the consuming populace (Uebersax et al, 1989).
The overall objective of this study is to investigate the various processing methods and their effects on the protein and cyanide content of African yam bean in conclusion, before the commencement of any research or project, there is meant to be aim/aims of such research.
As such, the aims of this study include:-
1. To determine the hydrogen cyanide content of the flour.
2. To analyse for the crude protein content of the flour.
3. To determine some of the functional properties of the flour.
4. Determination of the chemical composition of the flour.
5. To determine the bulk density of the flour.
Influence Of Processing Methods On The Protein And Cyanide Content Of African Yam Bean Sphenostylis Stenocarpa:
The influence of processing methods on the protein and cyanide content of African yam bean (Sphenostylis stenocarpa) is an important aspect of food science and nutrition research. African yam bean is a leguminous crop grown in several African countries, and it is a valuable source of protein and other nutrients. However, like many other legumes, it contains varying levels of cyanogenic glycosides, which can release toxic cyanide when not properly processed.
Here are some key points on how processing methods can affect the protein and cyanide content of African yam bean:
- Cyanogenic Glycosides: African yam bean contains cyanogenic glycosides, primarily linamarin and lotaustralin. These compounds are stored in the plant as a defense mechanism against herbivores. When the plant tissue is damaged, such as during food processing, enzymes called linamarase can hydrolyze these glycosides to release cyanide.
- Detoxification: Processing methods are employed to reduce the cyanide content to safe levels. Common methods include soaking, boiling, fermentation, and sun drying. These processes can significantly reduce the cyanide content, making the yam bean safer for consumption.
- Soaking: Soaking the beans in water for an extended period before cooking can help leach out some of the cyanogenic glycosides. The water is usually discarded, and fresh water is used for cooking.
- Boiling: Boiling is one of the most effective methods for reducing cyanide content. Boiling yam beans in water for an extended period can cause the release of cyanide into the boiling water, which is then discarded.
- Fermentation: Fermentation is another method that can reduce cyanide content. During fermentation, microorganisms can break down cyanogenic glycosides. This method is commonly used in the production of traditional African foods like ‘fufu’ and ‘akara.’
- Sun Drying: Sun drying can reduce cyanide content, although it may not be as effective as boiling or fermentation. Drying can reduce the moisture content of the beans, potentially decreasing the cyanogenic glycoside concentration.
- Protein Content: The protein content of African yam bean is relatively high, making it a valuable source of dietary protein, especially in regions where animal protein is scarce. Processing methods may not significantly affect the protein content, as the primary goal is to reduce cyanide rather than protein.
In summary, processing methods play a crucial role in reducing the cyanide content of African yam bean to safe levels, making it suitable for consumption. While these methods can affect the nutrient content of the bean to some extent, their primary purpose is to eliminate the cyanide toxicity risk associated with the consumption of raw or improperly processed yam bean.