الفهرس 
Materials and mithodsOnly 14 pages are availabe for public view
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Abstract
SUMMARY
The following lines summerize the various topics
which were handled in the present investigation to study
the chemical composition of rapeseed oil and meal beside
the evaluation of such materials during feeding experiments.
The method of introducing this summary follows to
a great extent the line of approach used in the presentation
of the various topics dealt with in this dissertation.
1. Extraction of oils from two different ra eseed varieties:
Two different rapeseed samples of Brassica napus,
German and.French varieties were used in the present study.
The oils were extracted from the curshed seeds through
hot hexane, mixtures of chlorofom : methanol : water (2.1:
0.8) (skysylof method) and pre-pressing methods. The
percentage of oiI extracted with hot hexane from German
and French rapeseeds were 37.8% and 38.3% respectively.
Refractive index of oils under study were nearly
indntical. Specific gravity of the extracted oil with
Skysylof method showed higher value than the two other
oils. Acid values in this work were small and rather insignificant.
Oil of the German variety was little higher
in its saponification value i.e. 190.4 than the French
variety which amounted to 187.0. Iodine values of the
oils under study were relatively small. The unsaponifiable
matters ranged from 1.43 to 1.85% for the obtained oils.
The peroxide values and thiobarbituric acid mumber in
all samples were relatively small.
2. Fatty acid composition of rapeseed oils (German and
French) varieties:
Saturated fatty acids palmetic (C16:O) and stearic
(C
I8
: 0) were found in the oils extracted from different
methods of German variety amounted 3.9% and 2% respectively
while arachidic (C
20
:0) and behenic acid (C22:0) were
detected in lower amounts. The major constituents of unsaturated
fatty acid in oils of German variety were CIS: l’
CIS: 2 and C
18
: 3. Oleic acid was the most prevalent one
and pre-pressing method yielded the highest oleic acid
content i.e. 65.6%. Linoleic acid ranged from 18.1% in
pre-pres sing method to 19. 2% obtained in skysy lof method.
Linolenic acid was present in all oils in relatively small
amounts. Moreover, gadoleic (C20:l) and erucic (C22:1)
were detected in low amounts and ranged between 1.4 to
1.5% and 0.6 to 0.7% respectively. The ratio between total
unsaturated to total saturated acids (TUfTS) for German
variety of rapeseed oil was 13.7:1.0.
Palmetic (C
16
:
0
) and stearic JC18:0) were also present
the oils of French variety and ranged between 4.0 to
in
_. . . . _~ ---c
_. - - -- -- - - -
97
4.1% for the former and 1.7% for the latter while arachidic
(C
20
:
0
) and behenic (C
22
:
O
) were detected as minor component
fatty acids.
Oleic acid (C
18
:
l
) was present in rapeseed oils (French
variety) i.e. 52.1 to 53.1%. Linoleic acid (C18:2) and
linolenic acid (C
18
: 3) ranged from 17.2 to 17.7% and from
8.4 to 8.7% respectively. Gadoleic acid (C20:l) was detected
in the French variety with relatively high percentage
and amounted to 7.2%. Erucic acid (C22:1) was relatively
high in this variety in comparison with oils of German
variety and ranged from 7.2 to 7.4%. The total unsaturated
to total saturated (TU/TS) ratio of French variety rapeseed
oils ranged from (13.9:1.0) to (14.1:1.0). Such values
were higher than the values recommended for common edible
oils. In general the proportion of (TU/TS) of rapeseed
oil might be considered as imbalanced edible oil.
3. unsaponifiable matter of rapeseed oils
French) varieties:
(German and
Unsaponifiable matters of the crude oils of rapeseed
(German and French) varieties were fractionated using
GLC technique. The hydrocarbon of the German variety contained
14 different components amounted from 81.61 to
82.14% of the total unsaponifiable matter. The major hydrocarbon
was C
28
ranged from 52.28 to 53.47% followed by
a and C
26
• B-sitosterol and stigmasterol were the more
two main sterols and ranged from 9.38% to 10.08% and from
5.09% to 5.65% respectively followed by campesterol from
2.46% to 2.76%.
The hydrocarbon contents of French variety ranged
from 77.21 to 77.93% of the unsaponifiables with predominance
of C
24
which ranged from 39.77 to 42.16% followed
by C
23
and C
32
hydrocarbons. B-sitosterol and stigmasterol
were the main sterols and ranged from 13.18 to 13.92%
and from 6.02 to 6.66% respectively.campesterol was
present in small amounts and reached to 2.52%.
4. Biola ical evaluation of ra eseed oil (German variet ):
The extracted oil through hot hexane from German
variety of rapeseeds (Low erucic acid content e.g. 0.6%)
was choosen to be used in the feeding experiments beside
corn oil as control. The effect of these oils after feeding
on serum glutamate pyrovate transaminase (S.GPT), serum
glutamate oxaloacetate transaminase (S.GOT), alkaline
phosphatase, blood urea, blood sugar and total cholesterol
in serum were thourhgly studied.
When loW eurcic acid rapeseed (LEAR) oil was used
in the feeding experiment, it caused significant increase
in GOT comparing with corn oil. The change of (GOT) enz}~e
-- _._---- - _. - -
-- - -- .- - - ---- -----,-----_.-._ ..
99
serum seems to be related to erucic acid of rapeseed in
diet. A noticeable increase in GPT and alkaline phosphatase
1n the serum of rats after four weeks of erucic acid
rapeseed oil feeding. The level of blood urea slightly
increased than that of the normal range. Also, blood sugar
and total cholesterol highly significantly increased
than that of the initial reported values. It could be
concluded in this aspect that heart and liver functions
might be affected by feeding with rapeseed oil (LEAR)
and measuring the formentioned crieterias in blood could
be used as a good examination to measure the disturbance
arised from feeding with erucic acid rapeseed oil.
5. Chemical composition of rapeseed meal:
The meal after oil extraction with three different
methods from two different varieties of rapeseed i.e.
German and French, were analyzed for its moisture, protein,
reducing and non-reducing sugar, ash and glucosinolate
contents. Its percentages ranged from (7.8 to 8.6%), (34.2
to 38.2%), (4.42 to 5.12%), (6.68 to 7.77%), and 0.113
to 1.8mg/g respectively. In addition all samples under
study were relatively rich in P,K and Na while Fe and
Zn were present in a moderate values, and eu and Mil contents
were founded in relatively trace amounts. ~
In general German variety contained relatively smaller
amounts of glucosinolates than that of French variety,
100
These compounds was present in lowest amounts in the meal
produced through Skysylof extraction method from both
German and French varieties i.e. 0.113 and O.14mg/g respectively.
Although, rapeseed meal is considered as a good source
of protein and minerals, but the major problem involved
in its use as meal in animal nutrition owing to the presence
of glucosinolates. The detoxification of rapeseed meal
is now considered as an important step in improving its
feeding value.
6. Elimination’ of glucosinolates from rapeseed meal:
Rapeseed meal of German variety with lowest gluco-
\
sinolate contents i.e. ~.ll3mg/g was choosen to investigate
the effect of temperature and aqueous leaching, on its
glucosinolate content. The resulted meal after Skysylof
extraction method was heated at 10QGe and pH.G.
Heat treatrneht caused a slight decrease in total
protein content reached to 33.54% and a slight increase
in ash content. All element ,contents showed minute changes
after leaching experiment. In addition, total glucosinolate
compounds were highly decreased from O.113mg/g to O.002mg/g,
resembling about 98% reduction from the original toxic
principle.
101
7. Biological evaluation of rapeseed meal:
Rapeseed meal (German variety) was heated at lOOoC
for 30 min. followed by continueous leaching at 25°C and
pH 6. The resulted clean meal was used as the sale source
of protein in the biological evaluation experiments. The
untreated rapeseed meal and casein were used as control
diets. Evaluation of the treated meal was carried out
by measuring its effect on weight gain, alkaline phosphatase,
(GPT) and. gamma-glutamyl transferase (Y-GT) in
serum.
When untreated rapeseed meal was used as the sole
source of protein, it caused minimum increase in body
weight comparing with casein group, beside the rate of
mortality increased and reached 40% • On the other hand,
leached rapeseed meal increased the weight gain and no
mortality cases were recorded.
8. Effect of glucosinolate rapeseed meal on liver functions:
S.GPT,
increased in
alkaline
case of
phosphatase and
using crude rapeseed
/S-GT
meal
levels
in the
diet. A disturbance of liver function might occurred owing’
to the toxic principles in the meal. On the other hand,
leached rapeseed meals showed a reasonable and encouraging
results of the liver-function tests.