콩기름의 반복가열과 시험관내 소화가 콩기름의 산화안정성에 미치는 영향

초록

Purpose: This study investigated the oxidation stability of thermally oxidized food lipids during digestion by repetitively heating soybean oil and then applying it to an in vitro digestion model. Methods: Soybean oil was heated intermittently at 170°C for a total duration of 120 minutes, with 40 minutes of heating each on the first, sixth, and ninth days. Subsequently, the soybean oils were analyzed for fatty acid composition and primary and secondary lipid oxidation products (LOPs). The most oxidized soybean oil sample, 4-hydroxy-2-hexenal (HHE), and 4-hydroxy-2-nonenal (HNE) were then applied separately to an in vitro digestion model simulating the mouth, stomach, and small intestine. The digesta was collected after each digestion step and measured for primary and secondary LOPs and protein carbonyl. Results: The p-anisidine value (p-AV), as a marker of secondary LOPs, was the most dependable indicator of oil oxidation status among the fatty acids and LOPs, as heating duration increased. The in vitro digestion of thermally oxidized soybean oil increased conjugated diene and triene levels (p<0.05) but decreased p-AV levels (p<0.05). This indicated the progression of oil oxidation during digestion. In the in vitro digestion model with HHE and HNE, the secondary LOPs decreased during digestion due to their partial degradation and adduct formation with proteins, as demonstrated by a proportional increase in the protein carbonyl content. Conclusion: These findings suggest that LOPs in food can be progressively oxidized during digestion. Thus, bioaccessible/bioavailable LOPs may differ from the LOPs present in food. This should be considered when assessing the risk of LOPs in humans.

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