Effects of storage conditions of flour on the lipid oxidation of fried products during storage in the dark

초록

Quality of fried products is mainly deteriorated by lipid autoxidation. Lipid oxidative stability of fried products is affected by chemical composition and quality of raw materials’ and frying oil as well as storage conditions. Although lipid of fried products is mainly from frying oil, lipid in flour might affect the lipid oxidation of fried products because flour lipid mainly consists of unsaturated fatty acids (>80%). Objective of this study was to determine the effects of storage conditions of flour on the lipid oxidation of fried products during storage in the dark. Wheat flour was stored at 60℃ in the dark and at water activity (Aw) of 0.3, 0.5 or 0.8 for 28 days, and its dough was fried in soybean oil at 160℃ for 1 min. The fried products were stored at 60℃ for 15 days in the dark. Fatty acid composition analysis of fried products showed increase in palmitic acid and decrease in linoleic acid during storage at 60℃, resulting in U/S ratio decrease. Peroxide values, conjugated dienoic acid contents, and p-anisidine values of fried products increased with storage time of fried products, especially the value increases were rapid after 12 day storage. As storage time of flour increased, lipid oxidation of fried products made from stored flour tended to increase. However, lipid oxidation of flour and that of the fried products during storage at 60℃ were not influenced by water activity at which flour was stored. Storage time of flour had higher effects on the lipid oxidation of the fried products during storage at 60℃ in the dark than water activity for flour storage did.