ACIDOLYSIS OF SEVERAL VEGETABLE-OILS BY MYCELIUM-BOUND LIPASE OF ASPERGILLUS-FLAVUS LINK

The ability of mycelium-bound lipase of a locally isolated Aspergillus flavus to modify the triglyceride structure of vegetables oils was st udied. The catalysis involved the acidolysis sis of vegetable oils, su ch as palm olein, coconut oil, cottonseed oil, rapeseed oil, corn oil and soybean oil, with selected fatty acids (FA). The reactions were fo llowed against time, and the percentages of FA incorporated were deter mined by gas chromatography. Percentage of FA incorporated after 20-h reaction was in the range of 13 to 18%. Reaction between cottonseed oi l with lauric acid gave the highest percentage of incorporation (18%), followed by soybean oil with lauric acid (16%) and coconut oil with o leic acid (16%). The results indicated that the hydrolytic affinity of A. flavus lipase demonstrates an acyl group specificity toward short- chain FA (C-8-C-10). Changes in triglyceride profiles of each oil were also monitored by reverse-phase high-pressure liquid chromatography. In all products, there were increases in the concentrations of several existing triglycerides and formation of new triglycerides. The meltin g points of all acidolyzed vegetable oils were determined by different ial scanning calorimetry, and significant changes in melting profiles were noted.