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Methods of Emulsifying Linoleic Acid in Biohydrogenation Studies In Vitro May Bias the Resulting Fatty Acid Profiles
Author(s) -
Khiaosaard Ratchaneewan,
Leiber Florian,
Soliva Carla R.
Publication year - 2010
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-010-3440-1
Subject(s) - sonication , chemistry , linoleic acid , fatty acid , emulsion , chromatography , ethanol , in vitro , incubation , clinical chemistry , dry matter , lipidology , biochemistry , food science , biology , botany
The effects of three emulsifying methods on ruminal fatty acid biohydrogenation (BH) in vitro were compared. Using a static in‐vitro gas test system, four replicates of each treatment were incubated in buffered ruminal fluid. Hemicellulose (300 mg dry matter) was supplemented either with or without linoleic acid (9 c 12 c ‐18:2, 5% in diet dry matter) and incubated for 4 and 24 h. Three methods of emulsifying 9 c 12 c ‐18:2 were tested: (1) ethanol, (2) Tween ® 80, and (3) sonication. The products were then compared to non‐emulsified 9 c 12 c ‐18:2. Out of the three emulsifying methods tested, ethanol and sonication resulted in stable 9 c 12 c ‐18:2 emulsions, indicating good 9 c 12 c ‐18:2 distribution, while the Tween ® 80 emulsion was less stable. BH was strongly inhibited by treating 9 c 12 c ‐18:2 with ethanol and sonication at different steps of the BH‐pathway, resulting in changed concentrations of certain BH intermediates. The fatty acid profile generated from the major BH‐pathways of 9 c 12 c ‐18:2 with Tween ® 80 was comparable to that without emulsification after 24 h of incubation. We conclude that it is not recommended to emulsify lipids before incubating them in vitro when investigating fatty acid BH. If emulsification of 9 c 12 c ‐18:2 is necessary, Tween ® 80 seems to be the method that interferes least with BH.