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Comparative study of the autoxidation of TAG containing conjugated and nonconjugated C 18 PUFA
Author(s) -
Suzuki Rikako,
Abe Masayuki,
Miyashita Kazuo
Publication year - 2004
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/s11746-006-0942-3
Subject(s) - trolox , perilla , chemistry , autoxidation , perilla frutescens , bitter gourd , antioxidant , gourd , conjugated system , food science , organic chemistry , polymer , traditional medicine , medicine , raw material , momordica , dpph
Four TAG containing linoleate (soybean‐TAG), α‐linoleate (perilla‐TAG), conjugated linoleate (CLA‐TAG), and conjugated linolenate (bitter gourd‐TAG) were oxidized in the bulk phase at 50°C. The effects of α‐tocopherol and Trolox (6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid) on the oxidation of these TAG were also studied. Progress of oxidation was determined by measuring the oxygen consumption, peroxide formation, and polymer formation. The rates of oxygen consumption and polymer formation of bitter gourd‐TAG and CLA‐TAG were faster than those of perilla‐TAG and soybean‐TAG, respectively. The present results revealed that the main oxidation products of bitter gourd‐TAG and CLA‐TAG were dimers and polymers, whereas hydroperoxides were the main products in the oxidation of perilla‐TAG and soybean‐TAG. These differences in the oxidation of TAG were characterized mainly by oxidation of the main PUFA contained in each TAG, namely, linoleate (56.1%) for soybean‐TAG, α‐linolenate (54.5%) for perilla‐TAG, conjugated linoleate (69.5%) for CLA‐TAG, and conjugated linolenate (61.6%) for bitter gourd‐TAG, respectively. α‐Tocopherol and Trolox inhibited the oxidation of TAG. The inhibitory effect of these antioxidants was more effective against the oxidation of CLA‐TAG and bitter gourd‐TAG than that of soybean‐TAG and perilla‐TAG, respectively. This was probably due to the high rate at which the antioxidants inhibited the dimerization and polymerization of CLA‐TAG and bitter gourd‐TAG.