Oxidative stability of Triglycerides from Orbital Fat of Tuna and Soybean Oil in an Emulsion

抄録

Triglycerides (TGs) from orbital fat of tuna (tuna-TG) and from soybean oil (soy-TG) were dis-persed in a buffer with milk casein and their oxidative stabilities in an emulsion were compared with those in the air. Since the average number of bisallylic positions in tuna-TG molecule was higher than that in soy-TG molecule, tuna-TG was more susceptible to oxidation than soy-TG in the air. However, tuna-TGbecame oxidatively more stable than soy-TG in an emulsion. PV of soy-TG increasedrapidly after 100 h of oxidation in an emulsion, but such an increase was not observe in the oxidation of tuna-TG. Gas chromatographic analysis also showed that 94.0±3.8% of polyunsaturated fatty acids (PU-FAs) in tuna-TG remained unchanged after 240 h of oxidation in an emulsion, while soy-TG was more rapidlyoxidized inan emulsion with loss of 76.2±1.1% of PUFAs after 240 h of oxidation. These resultsshow the possibility that fish oils may be protected from their oxidations by emulsification.