CHAPTER THREE
MATERIAL AND METHOD
3.1 Source
of Raw Material
Palm kernel oil was obtained from fermented and boiled
palm fruits for the two samples, it was obtained from the palm fruits after the
processing of fermented and boiled palm oil from the fruits. in food processing
laboratory of Ebonyi State University Abakaliki.
3.2
Sample Preparation
Palm kernel processing starts with the shelling of the
palm nuts, after sundry 2 to 3 days. the shelling was performed using two stone
to crack each nut and separating the kernel from shell simultaneously. 1,200g
of each sample both the fermented and boiled palm kernel was measured in the
food science and technology chemistry laboratory of Ebonyi State University
Abakaliki using metler balance model (p 121). The weighed samples was crushed
at meat market in Abakaliki Capital Tertiary. The sample was crushed to small
particles to easy the oil extraction .The crushed samples was soaked in 60ml of
n-hexane concentration for 24hours.
Flow Chart Process of Palm Kernel Oil Extraction
raw materials (palm kernel)
weighing
crushing
soaking(n-hexane)
filtering palm kernel cake
oil in n-hexane (mixture)
pour into soxlet apparatus
heat at 70oc (using heating mantle)
raw palm kernel oil recovered
packaging
3.3 Method
of Oil Extraction
Soxhlet method of oil extraction was
used to extract the oil .the oil extracted will be subjected to the following
analysis.
(1)
saponification
value
(2)
iodine
value
(3)
peroxide
value
(4)
free
fatty acid (FFA)
(5)
moisture
content
(6)
melting
point
(7)
freezing
point
3.4 Determination of Moisture Content
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 disccator about 5g of the homogenous sample was weighed into previously
weighed dish and placed in a thermostatic well ventilated oven maintained at
105c for 3hours. at the end of the time, the dish was quickly transferred into
disccator and allowed to cool to room temperature . The weight of the dish and
sample was recorded. During and after cooling was repeated at hour interval
until a constant weight was obtained. The percentage moisture content was
calculated from the weight loss of sample.
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% moisture content = W2-W3 X 100W2-W1 1
W1 = initial weight of empty crucible.
W2 = weight of crucible and oil sample
before drying.
W3 = final weight o crucible and oil sample
after drying.
3.4.1 Acid Value Determination
The
method described by Onwuka(2005) will be used 1g of the oil will be weighted
and poured into (250ml) conical flask. 25ml ethanol and 1ml phenolphthalein,
will be added and the mixture carefully neutralized with 0.1N Noah to change to
a pink colour and point. The acid value will be calculated as:
Acid value = Titer (xml) x 5.61
Weight of sample
used------------------------2
3.4.2 Iodine Value Determination
The method described by Onwuka
(2005) will be used. One grams of the oil weighed using a meter balance will be
poured in to a 250ml conical flask and 10ml of water added. The resultant
mixture will be titrated with 0.1m thiosulphate (Na2 SO4) solution using 1%
starch as an indicator. A blank will be carried out without the oil. The iodine
value will be calculated as:
Iodine value = (b-a) x 1.269
Weight
of sample used ----------------------3
Where b = titer value of blank
a = titer value of the sample
3.4.3 Specification Value
Determination
The method described by Onwuka
(2005) will be used, two grams of the oil will be weighed into a conical flask
and 25ml ethanolic potassium hydroxide solution added to it. A reflux condenser
will be attached to the conical flask after which the flask content will be
headed in boiling water for 1 hour with frequent shaking. About 1ml
phenolphthalein (1%) solution will be added and solution then titrated when hot
with excess alkali. A blank will also be carried out without addition of
extracted oil.
Specification value = (b-a) x28.05)
Wt (g) of sample used
Where
b = blank liter value
a = sample liter value
3.4.4 Determination of Peroxide Value
The
method described by Pearson (1976) will be used to determined the peroxide
value of the palm oil.1g of the oil sample extracted will be weighed in to a
clean conical flask followed by 1g of powdered potassium iodide and 10ml of the
solvent mixture (2 volume glacial acetic acid and 1 volume chloroform i.e 3.1)
the conical flask will be placed on a boiling water bath to boil the mixture
vigorously for a time not exceeding 30 seconds; 20ml of potassium iodide
solution (5%) will be added and the mixture titrated with 0.002n sodium
thiosulphate using (1%) starch as an indicator. Peroxide value is given by
peroxide value =
(b-a) Nx100
weight
of the sample
-----------------5
where b = titer value of blank
a =
titer value of the sample
3.4.5 Melting Point
Described how this will determine.
Palm oil sample (some) will be placed in a curable or beaker and frozen in a
refrigerator. After this a thermometer will inserted into the frozen oil. Beaker containing oil and thermometer will
placed in hot water bath to warm. Temperature at which the oil start melting
and completely melt will be recorded as the melting point range.
3.4.6 Freezing Point
Fatty
mill litter of the oil sample will poured into crucible dish. Hen crucible dish
and be place in a refrigerator. The temperature at which the oil samples being
to freeze will be noted as the freezing point of the oil.
3.5 Statistical
Data
The
data generated from study will be subjected to analysis of variance (ANOV) at
5% degree of significance and the mean shall be separated using turkey test,
(Okprie, 2006).