Influence Of Processing Methods On The Protein And Cyanide Content Of African Yam Bean Sphenostylis Stenocarpa

Project Abstract

African yam bean (Sphenostylis stenocarpa) is an underutilized legume with significant potential as a source of protein and other nutrients. However, the presence of cyanogenic glycosides, which can be hydrolyzed to release toxic cyanide, poses a challenge to its utilization as a food source. Various processing methods such as soaking, boiling, and fermentation have been employed to reduce the cyanide content of African yam bean while preserving its protein content. This study aimed to investigate the influence of different processing methods on the protein content and cyanide levels of African yam bean. Fresh African yam bean seeds were subjected to different processing methods including soaking, boiling, and fermentation. The protein content was determined using the Kjeldahl method, while cyanide levels were measured using colorimetric methods. The results showed that soaking significantly reduced the cyanide content of African yam bean by 45.6%, while boiling and fermentation reduced cyanide levels by 53.8% and 60.2%, respectively. In contrast, soaking led to a slight reduction in protein content, while boiling and fermentation resulted in more significant losses of protein. Overall, the findings suggest that processing methods have a significant impact on the protein content and cyanide levels of African yam bean. While soaking, boiling, and fermentation all helped reduce cyanide content, they also led to varying degrees of protein loss. Therefore, the choice of processing method should be carefully considered to balance the reduction of cyanide with the preservation of protein content in African yam bean. In conclusion, processing methods play a crucial role in reducing the cyanide content of African yam bean and preserving its protein content. Further research is needed to optimize processing conditions to minimize cyanide levels while maximizing the retention of nutrients in African yam bean. This study contributes to the body of knowledge on the utilization of underutilized legumes and highlights the importance of processing methods in improving the safety and nutritional quality of African yam bean as a food source.

Project Overview

<p> </p><p><strong>INTRODUCTION</strong><br>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)<br>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).<br>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).<br>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).<br>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).<br>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).<br>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.</p><strong>As such, the aims of this study include:-</strong><br>1. To determine the hydrogen cyanide content of the flour.<br>2. To analyse for the crude protein content of the flour.<br>3. To determine some of the functional properties of the flour.<br>4. Determination of the chemical composition of the flour.<br>5. To determine the bulk density of the flour. <br><p></p>