Bioscience Methods 2017, Vol.8, No.2, 18-30
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purposes. A better understanding of the roles of plant parts in increasing the shelf life of farm produce has helped
in the creation of more effective and safer means of pest and microbial control (Oladotun and Deborah, 2013).
Ocimum gratissimum
(L.) commonly known as scent leaf is an herbaceous, perennial shrub of the family
Lamiaceae, often found growing around villages in Nigeria with its characteristic smell for seasoning dishes
(Okujagu, 2008). Owalade et al. (2000) reported that leaf extracts of
O
.
gratissimum
and
Verononia amygdalina
effectively protected maize seeds from seed borne infection of
Fusarium moniliforme
. Also Okoi and Afuo (2009)
reported that crude extracts of
O. gratissimum
effectively exhibited antifungal activity on
Cercospora
arachidicola
, the causal organism of leaf spot disease of groundnut.
Vernonia amygdalina
, variously known as bitter leaf is a tropical shrub, which range from 1-3 m in height with
petiole leaf of about 6mm in diameter, and elliptic in shape (Igile et al., 1995). The leaves are dark green coloured
with a characteristic odour and a bitter taste. The species is indigenous to tropical Africa and is found wild or
cultivated all over sub- Saharan Africa (Bosch et al., 2005). All parts of the plant are pharmacologically useful.
Both the roots and leaves are used in phyto-medicine to treat fever, hiccups, kidney disease and stomach
discomfort, among others (Gill, 1992; Hamoiona and Saffaf, 1994). Anti-helmitic and anti-malarial properties
(Abosi and Raserika, 2003) as well as anti-tumourigenic properties (Izevbigie et al., 2004) have also been reported
for extracts from the plant. Other studies have demonstrated hypoglycaemic and hypolipidaemic effects of the leaf
extract in experimental animals (Akah and Okafor, 1992; Nwanjo, 2005). The study is therefore aimed at
providing information on the anti-microbial potentials of
Ocimum gratissimum
and
Vernonia amygdalina
crude
extract on
Sarotherodon galilaeus
snacks.
1 Materials and Methods
1.1 Source of raw materials
The samples used for this study were taken from sample used for nutritional assessment of fish snack made from
Sarotherodon galilaeus
. 940 grams of
Vernonia amygdalina
and 827 gms of
Ocimum
gratissimum
leaves and
every other ingredient for composite spice “suya spices” and other materials used were purchased from Akungba
Akoko, Ondo state, Nigeria.
1.2 Production of spices
The spice was prepared from the following ingredients; Human edible Groundnut cake locally called “kulikuli”,
Ginger, Garlic, Cayenne pepper flakes, Black Pepper, Cooking salt and African Negro pepper. These ingredients
were ground into powdery form to increase surface area and improve attachment. The spice was similar to “Yaji”
that is “suya” spice (Table 1).
Table 1 Spice composition
ingredients
grams of ingredient
proportion in spice (%)
edible groundnut cake
765
85
ginger
40.5
4.5
garlic
30.6
3.4
cayenne pepper flake
30.6
3.4
black pepper
17.1
1.9
common salt
15.3
1.7
African negro pepper
0.9
0.1
total
900
100
1.3 Preparation of crude extracts and brine plus crude extract
Nine hundred and forty grams of
Vernonia amygdalina
and 827 gms of
Ocimum
gratissimum
leaves were quickly
washed in jet of tap water and rid of excess water before squeezing into separate bowls to obtain crude extract.
The extracts were diluted to acceptable taste based on taste range finding test.
Ocimum
gratissimum
was diluted
with potable water to give 54.5% v/v concentration; also,
Vernonia amygdalina
was diluted with potable water to
