Abstract
The adipose tissue fats from different dept sites of swine with soft fat and normal fat were investigated by stereospecific analysis and argentation thin-layer chromatography procedure to reveal some features of soft fat pork lipids. Fats of swine with soft fat contained more C18:2, C18:3 and total unsaturated fatty acids and less C16:0 and C18:0 acids than those of normal fat. The adipose tissue lipids, both of soft fat and normal fat, had similar fatty acid distributions in triacylglycerols with most of the C14:0, C16:0 and C16:1 acids in position 2 and much of the C18:0 acid in position 1, although kidney leaf fat of swine with normal fat with high C18:0 acid content had significant amount of this acid in position 3. On the other hand, C18:1 and C18:2 acids preferentially esterified to positions 1 and 3. The lower C16:0 acid concentration of soft fat than that of normal fat were mainly accounted for the difference of this acid content in position 1. And the large amounts of C18:2 acid in soft fat were resulted from the higher concentrations of this acid in all three positions of soft fat triacylglycerols than in those of normal fat. Back fats of soft fat pork had less concentrations of C18:0 acid in psition 3 than those of normal fat in corresponding of position, and it seemed that these decreased amounts of C18:1 acid in position 3 of soft fat triacylglycerols were largely compensated by the increased amounts of C18:2 acid in the same position. The amounts of component triacylglycerols of adipose tissue fats were calculated with results from the known fatty acid distribution in the intact triacylglycerols, assuming a 1-random, 2-random, 3-random arrangement. Fats of swine with soft fat contained more S2U and U3 triacylglycerols and less S3 and S2U than those of the corresponding depot site fats of swine with normal fat. The triacylglycerols of adipose tissue fats were separated according to degree of unsaturation by argentation thin-layer chromatography. The proportions of the more saturated triacylglycerol species such as S3 and S2M were significantly less and the proportions of the more unsaturated species with three or more double bonds such as SMD, SD2 and M2D were greater in soft fat pork lipids than in normal fat. (Abbreviations used in this were as follows; S: saturated, U: unsaturated, M: monoenoic, and D: dienoic fatty acid)
