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In vitro hydrolysis of natural and synthetic γ‐linolenic acid‐containing triacylglycerols by pancreatic lipase
Author(s) -
Huang YungSheng,
Lin Xiaorong,
Redden Peter R.,
Horrobin David F.
Publication year - 1995
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02635646
Subject(s) - hydrolysis , chemistry , lipase , evening primrose oil , lipolysis , palmitic acid , linoleic acid , triolein , linolenic acid , fatty acid , biochemistry , food science , enzyme , adipose tissue
The present study compared the in vitro hydrolysis of two 18:3n‐6‐rich oils—evening primrose oil (EPO) and borage oil (BO)—and different synthetic 18:3n‐6‐containing triacylglycerols (TG). Incubation of EPO and BO with pancreatic lipase lipolyzed 18:3n‐6 from the TG species. The rate of lipolysis of TG species containing two or three molecules of 18:3n‐6, which comprised 36% of total 18:3n‐6 in BO and only 7% in EPO, was significantly slower than those containing only one molecule of 18:3n‐6. This was found especially in those with two molecules of linoleic acid, which constituted 20% of total 18:3n‐6 in BO, whereas over 80% were present in EPO. In a separate study, various synthetic 18:3n‐6‐containing TG were also subjected to in vitro hydrolysis by pancreatic lipase. Results showed that release of 18:3n‐6 from the sn ‐1/ sn ‐3 positions was significantly slower when two other stereospecific positions in the same TG molecule were occupied by either palmitic acid (16:0) or monounsaturated (18:1 and 20:1) fatty acids than when occupied by 18:2n‐6. The rate of hydrolysis of sn ‐2‐γ‐linolenyl‐ sn ‐1(3)‐diacylglycerol to form sn ‐2‐mono‐γ‐linolenyl glycerol was also significantly slower when both the sn ‐1 and sn ‐3 positions in TG molecules were occupied by either saturated fatty acids (16:0 and 18:0) or long‐chain monounsaturated fatty acids than when occupied by 18:2n‐6. These findings suggest that the stereospecific position of 18:3n‐6 in TG molecules and the constituent of its neighboring fatty acids modulated availability of 18:3n‐6 from 18:3n‐6‐containing TG or 18:3n‐6‐rich oils.