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In-vitro DIGESTIBILITY OF OILS AND FATS [Vol. XX Part IV,
Relative digestibility of fats in presence of activator
(a) Preparation of pancreatic lipase. Fresh pancreas from the slaughter house
were separated from the adhering fatty material and minced well. It was sub-
sequently treated with successive quantities of acetone, acetone-ether (1:1) mixture
and ether according to the procedure of Willstatter and Waldschmidt-Leitz [1923].
The defatted material was ground to a fine powder and sieved. For preparing the
extract 10 gm. of the fine powder was triturated with 60 ml. of 85 per cent aqueous
glycerol and shaken for 4 hours at room temperature. The coarse particles were
separated by centrifugation and the turbid extract was used for experiment.
(b) Digestion trials. The digestion was carried out as follows. A series of
test tubes were set up containing 2.0 gm. of fat and 1.0 ml. of buffer (NH 3 NH 4 Cl,
pH 9.3). The bile salt used for the present study was Merck's pure sodium tauro-
cholate and 1.0 ml. of this solution was added to each test tube. Finally, 10 ml.
of the enzyme extract was added and immediately shaken with the hand for three
minutes and kept in thermostat at 350.1ºC.
The tubes were removed for titra-
tion at known intervals and the contents quickly transferred to a flask containing
50 ml. of 95 per cent alcohol, and 10 ml. of ether added. The mixture was titrated
against 0.1-N alkali using phenolphthelein as indicator. The results are corrected
for the control and are expressed in ml. of 0.1-N alkali required to neutralise the
fatty acids in the reaction mixture after a known period of digestion. Four samples
of fats were taken at a time with cow ghee as a standard for comparison. Twenty
samples of hydrogenated fats from different manufacturers (different brands) were
also used for finding out their relative digestibilities. The results are presented
in Table I and Fig. 1.
DISCUSSION
From Fig. 1, it can be observed that the rate of digestion of ghee from buffalo,
goat and sheep follow the same trend as cow ghee. The body fats from cow, buffalo,
goat and sheep were found to be digested at a lower rate as compared to cow ghee
under the same conditions. As the body fats have very high melting points (49.4
to 52.3ºC.) which is perhaps the reason for their lower digestibilities. The oils
were found to be better digested than the body fats which confirm the findings
from in-vivo experiments carried out by Bhalerao et al. [1947] except in the case
of mustard oil, which was found to be poorly digested in in-vivo experiments. Coco-
nut oil was found to show equal or even better digestion than cow butterfat by
in-vitro experiment.
All the vanaspaties prepared from groundnut, cottonseed and sesame oils were
digested slightly better than body fats but the digestion rate was significantly
poorer as compared to oils from which these were prepared. There appears to be
no significance between the vanaspaties of the same origin and having different
melting points used in the present experiment as seen from Fig. 1. In general, the
rate of digestion of the vanaspaties from groundnut, sesame and cottonseed appears
to be almost the same. These observations are confirmed from the results of
another set of experiments wherein the rate of digestion of 20 samples of hydro-
genated oils are compared with cow butterfat (Table I).