CHAPTER THREE
MATERIALS AND METHODS
3.0 SOURCE
OF RAW MATERIALS
Fresh palm fruit that was used for
this work was obtained from Ohaozara local government in Ebonyi State. The adulterant red dye was
obtained from Abakpa, Main Market Abakaliki ,Ebonyi State. The yam tuber will
also be obtained from the same market.
3.1 SAMPLE
PREPARATION
The palm fruits were divided into
two portions of 2kg each. One out of the
two portions was processed without the addition of the adulterant and this
served as the control. The palm fruit was boiled for 45 minutes cooled and then
pounded using pestle and mortar. Warm water was use to wash the pulp and the
crude oil skimmed off and heated. The adulterant was added and mixed thoroughly.
The oil samples was subjected to analysis of iodine value, moisture content,
free fatty acid , peroxide value and specific density after which it was used
to eat yam.
3.2 PRODUCTION
PROTOCOL OF CRUDE PALM OIL
Harvested palm fruit
Boiling (45 minutes)
Boiling (45 minutes)
Pounding into pulp
Extraction of oil
Heating
Filtering
Palm oil
Addition of
adulterants
3.2.1 BOILING
PROTOCOL (YAM)
Yam Tuber
Peeling
Slicing
Washing
Washing
Sensory evaluation
3.3 PARAMETERS
THAT WERE EVALUATED
3.3.1
MOISTURE CONTENT DETERMINATION
The hot oven method (NAFDAC, 1982)
was used in the determination. Porcelain dish was thoroughly washed and dried
in the oven after which it was allowed to cool in the desiccators. About 5g of
the homogenous oil sample was weighed into previously weighed dish and placed
on a thermostatic well ventilated oven maintained at 1050C till
constant weight. At the end the dish will be recorded.
The percentage moisture content will
be calculated from the weight loss of sample, according to the equation:
%
moisture content
Where,
W1 = Initial weight of empty crucible
W2 = Weight of crucible + oil before drying
W3 = Final weight of crucible + oil after drying
3.4 IODINE
VALUE DETERMINATION
Iodine value was determined using
chemical method of food analysis as described by (A.O.A.C, 2002). About 1g of
the oil sample was weighed into a glass Stoppard bottle of 25ml and 10ml carbon
tetra chloride added to it. This was dissolved with 20m; wiji’s solution after
which the stopper that was moisture with potassium iodine solution will be
inserted. This was mixed and allowed to stand in dark compound for 30 minutes.
At the expiration of time, 15ml potassium iodine solution and 100ml distilled
water was later titrated with standard 0.1m sodium thiosulphate solution using
starch as indicator. A black test will be carried out commencing with 10ml of
carbon tetrachloride.
Iodine value was calculated as follows:
Iodine
value
(g/100g)
Where,
b = value of the standard thiosulphate by the blank
a = value of standard sodium thiosulpahte used by the sample
3.5 PEROXIDE
VALUE DETERMINATION
This was determined by A.O.A.C (2002).
About 1g of oil sample was weighed into a clean dried conical flask and 1g of
powdered potassium iodide and 20ml of solvent mixture (200) glacial acetic acid
and cool chloroform) was added to it. The mixture was placed in a boiling water
bath for 60 seconds. The content was poured quickly into a flask containing
20ml potassium iodide solution (5%) and the flask was washed twice with 25ml of
water, the mixture was titrated with 0.002m sodium thiosulphate using starch as
indicator Lamey, noting the end point. A blank test was carried out.
Peroxide
value = 2 x [b-a]
(mgkpH/g)
weight
of sample
3.6 FREE
FATTY DETERMINATION
This was determined using the method
recommended by NAFDAC (1982). About 1g of the oil sample was weighed in a dried
conical flask of known weight after which it was dissolved by adding 50ml of
mineralized solvent of diethyl and ethanol. This was soaked in the water bath
for 5 minutes and 2-3 drops of phenolphthalein Indicator will be added and
titrated. This was noted when a pale pink colour appears. The percentage FFA is
calculated as palmitic acid, as follows.
FFA = Titre
value [me] x 0.0282
Weight of sample used.
3.7 SPECIFIC
DENSITY
The
method describe by Onwuka (2005) was employed. Density bottles of 50ml was
thoroughly washed with detergent, water,dried and weighed.
The
bottles was filled with distilled water and weighed. After this the bottle was
emptied, dried
and
then filled with oil and weighed. The specific density of oil was calculated
as;
specific
density = weight of xml of oil
weight of xml
of water
where
x is the volume of the bottle.
3.8 SENSORY
EVALUATION
Sensory evaluation was carried out
for consumer acceptance and preference using semi-trained panelist comprising
of students and staff of the department of food science and technology, Ebonyi
State University. Quality that was assessed include, colour, taste, aroma,
mouth feel and general acceptability. A time point hedonic scale was used with
9 and 1 representing like extremely and dislike extremely respectively. The
mean score was analyzed using analysis of variances (ANOVA) method and
different separated using LSD test.
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