양파즙 처리가 가열산화된 리놀렌산의 in vitro 소화 중 산화안정성에 미치는 영향

초록

Purpose: This study examined whether lipid oxidation and antioxidation processes in food continue during digestion after consumption. Methods: A 3.125% (w/w) linolenic acid in tricaprylin solution was heated to 36.5℃ for up to 12 hours, and primary and secondary lipid oxidation products (LOPs) were measured. Subsequently, a three-hour oxidized linolenic acid sample (Oxi-LNA), displaying characteristic changes in LOPs, was applied to an in vitro digestion model simulating the mouth, stomach, and small intestine. Two experimental groups (Oxi-LNA+S1-OJ and Oxi-LNA+S4-OJ) were prepared as follows. Onion juices (S1-OJ and S4-OJ), derived from onions fertilized with sulfur once or four times during cultivation, were used as antioxidant ingredients and applied to the in vitro model along with Oxi-LNA. The digested matter was collected after each stage of digestion (mouth, mouth-stomach combination, and mouth-stomach-small intestine sequence), and the primary and secondary LOPs were measured. Results: As digestion progressed, the ‘Oxi-LNA’ group exhibited a significant increase in the level of conjugated triene (p<0.001) and decreases in hydroperoxide content (p<0.05) and secondary LOPs (p<0.01), suggesting that lipid oxidation proceeded during digestion. The ‘Oxi-LNA+S1-OJ’ and ‘Oxi-LNA+S4-OJ’ groups showed a significantly higher hydroperoxide content (p<0.01) and lower levels of secondary LOPs (p<0.001) compared to the ‘Oxi-LNA’ group, which phenomenon was noticeable in the small intestinal digesta. This suggests that onion juice retards the decomposition of hydroperoxides into secondary LOPs. Thus, it functions as an antioxidant during digestion. Conclusion: These findings suggest that lipid oxidation and antioxidation processes occur continuously within the food and throughout the digestive process after food ingestion.

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