INFLUENCE OF PROCESSING METHODS ON THE PROTEIN AND CYANIDE CONTENT OF AFRICAN YAM BEAN SPHENOSTYLIS STENOCARPA
INFLUENCE OF PROCESSING METHODS ON THE PROTEIN AND CYANIDE CONTENT OF AFRICAN YAM BEAN SPHENOSTYLIS STENOCARPA
CHAPTER ONE
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.
