CHAPTER
ONE
1.0 INTRODUCTION
Ugba also called ukpaka is a popular food delicacy in Nigeria
especially among Ibo ethnic group. It is rich in protein and is obtained by a
solid state fermentation of the seed of African oil bean tree (Pentaclethra macrophylla Benth). It is essential food item from various traditional ceremonies
where it is mixed with slices of boiled stock fish (ugba and okpoloko). The
natural fermentation of the seed which at present is still done at the
house-hold level, renders the production nutritious, palatable and non-toxic
(Enujiugha, 2002).
Its
production, like many African fermented foods depends, entirely on mixed
fermentation by microorganism from diverse source.
Some
of these seeds have been exploited as soup bases such as Gbegiri from Vigna unguicuata
(Akanbi, 1992). Others are fermented and used as condiments and seasonings such
as okpei from Prosopis africana (Achi, 1992) and ogiri from Ricinus cummunis
(Odunka, 1989). Another of such seeds is the African oil bean seed (Pentaclethra macrophylla Benth), a highly nutritious leguminous crop seed abundant in
the rain forest areas of west and central Africa.
Pentaclethra macrophylla Benth is a large woody plant abundant in the rain forest areas
of west and central Africa. It’s origin in Nigeria is believed to be around
1937 (Ladipo, 1984); where it is found in the South Nigeria, (Mbajunwa et al,
1998).
“Ugba”
Pentaclethra macrophylla Benth belongs to the Family
Leguminosae and sub-family microsoideae (Keay, 1989 and NFTA, 1995).
Ugba
seeds are irregular and oval, they are flat, black and hard pods. It is
composed of oil, protein and small amounts of carbohydrate (Obeta, 1982).
Production
of Ugba is still on age old traditional family in the rural area. The
fermentation depends on random inoculation of boiled slices of the oil bean
seed by microorganism within he immediate environment. Earlier report attribute
the sources of the micro-organism to the leaves used in packaging, human
handling, container and utensils used in processing (Obeta, 1993, Odunfa &
Oyeyiola, 1985).
A
number of researches have been carried out to know what causes this
fermentation, and was attributed to micro-organisms that are probably
introduced through the air, water, and banana leaves. Organisms such as Micrococus roseus, Micrococcus luteus, Leuconostoc mesenteroides, Staphylococcus aureus, Staphylococcus
epidermidis, Bacillus substilis, Bacillus megaterium and
Bacillus circclans, E-Coli
Fermented
African oil bean seed (ugba), has a high rate of susceptibility to microbial
spoilage and therefore has a very short self life of 1-2 weeks (Enujiugha &
Olajundoye, 2001).
Manifestation of food spoilage are many
and vary typically resulting in an off smell, colour, taste and texture.
Reports by Mbajunwa (1998) Obeta, (1983) and
Nwagu et al. (2010) indicates that micrococcus
species do not play an active role during microbial fermentation of Ugba.
However,
further work on spoilage association of ugba by Nwagu et al (2010)
showed that the population of Micrococcus sp increased with increase in keeping time
of ugba. This indicates the ability of micrococcus to thrive in the alkalophilic environment
while constituting as a spoilage organism of ugba. This may be attributed to
the ability of microorganism to produce lipase, lipase, or protease able to utilize
protein, carbohydrate or lipid content of ugba as source of nutrition (Njoku et al.,
1990).
Lipase are defined as glycerol ester hydrolases (EC3.1.1.3) hydrolyzing
tri-di and mono-glycerides present at oil-water interface (Saxena et al, 1999).
Some lipases are also able to catalyze esterification, trans-esterification and
enantioselective hydrolysis reaction
(Nine et al, 2001, Shintre et al, 2002). The interest in microbial lipase
production has increased in the last decades, because of its large potential in
a wide range of industrial applications and additives in food processing
(flavour modification).
1.1 Aims
and Objectives
This work is aimed at the following;
a.
isolating
micrococcus from fermented ugba
b.
producing
lipase from the micrococcus from ugba
