This study was conducted to investgate the effect of gamma irradiation on the lipid oxidation, olfactoryproperties, fatty acid isomer and volatile compound profiles of five different oil sources. Three plant oils, canolaoil, corn oil and soy oil, and two animal fat, tallow and fish oil, were irradiated with 0, 5, 10, and 20 kGy levelof dose by Co-60 as a radiation source.
Lipid oxidation parameters, FFA, POV and TBARS, were determined according to the AACC and AOCSmethod. Olfactory property of irradiated oil sources was analyzed using electronic nose (FOX3000, AlphaMOSCo., France) with 12 metal oxide sensors and the result was interpreted using principle component analysisprogram. Fatty acid isomer profiles and volatile compound profiles of irradiated oils were also measured by GCand GC-MS, respectively.
Although the free fatty acid level of oil were the highest by high dose level (20 kGy) of irradiation, changesof both TBARS and POV values by gamma irradiation were varied between oil sources and irradiation level ofdose. Electronic nose analysis showed a distinct difference among dose levels of irradiation. Although there wasno new volatile compound produced by gamma irradiation, amounts of each volatile compounds were increasedby irradiation. Only cis isomer, 9c12c15c of linolenic acid was dose-dependently decreased as irradiation levelincreased but there was no difference among other isomer profiles of linoleic acid and linolenic acid by gammairradiation.
This study showed that changes in physico-chemical properties of both plant and animal oil were remarkableby gamma irradiation. Therefore, a further study should be needed to scrutinize the interaction among lipidoxidation, production of volatile compounds and off-flavor, and isomerization of fatty acid by gamma-irradiation.