Fatty acid and molecular weight distributions of triacylglycerols in developing winged bean seeds

Abstract

The positional distribution of fatty acids (FA) and the molecular weight distribution of triacylglycerols (TG) in developing winged bean (Psophocarpus tetragonolobus) were studied. There were marked changes in the positional distribution of FA in the TG as well as in the molecular weight distribution of the TG during seed development. The levels of palmitic acid(16:0) and stearic acid (18:0) at the sn-1 position decreased whereas the levels of the same acids in the sn-3 position increased as the seed developed. Oleic (18: 1), linoleic (18:2) and linolenic (18:3) acids were found in all three positions of the TG molecules but most were found in the sn-2 position. Behenic acid (22:0) was preferentially esterified to the sn-3 position even at the early stage (3 WAF) of seed development but its level in the sn-1 and sn-3 positions increased as the seed developed. The levels of 16:0 and 18:0 decreased while the level of 22:0 and the proportion of TG with larger molecular weights, that is, C56, C58 and C60 also increased as the seeds developed. Our findings indicate that winged bean seed oil may be atherogenic as compared to peanut oil. © 1989.