Effects of Flour Storage Conditions on the Lipid Oxidation of Fried Products during Storage in the Dark

The effect of flour storage conditions on the lipid oxidation of fried products during storage was studied. Wheat flour was stored at $60^{\circ}C$ in the dark and at water activity (Aw) of 0.3, 0.5, or 0.8 for 21 days. The square-shaped dough ($2{\times}2{\times}0.1\;cm$) made with the stored flour and water was fried in soybean oil at $160^{\circ}C$ for 1 min. The fried products were stored at $60^{\circ}C$ for 15 days in the dark. The degree of lipid oxidation of the fried products was evaluated by conjugated dienoic acid (CDA) content and p-anisidine value (PAV). Both CDA content and PAV of the fried products increased with lengthening storage time of the fried products, suggesting that longer storage of the fried products raised the lipid oxidation. Furthermore, the lipid oxidation of the fried products made with flour that had been stored for a longer time tended to be higher than that of those made with unstored or short-term-stored flour. However, Aw at which the flour was stored did not significantly affect the lipid oxidation of either flour or the fried products during storage. The storage time of flour clearly exerted a greater effect than Aw on the lipid oxidation of the fried products during storage at $60^{\circ}C$ in the dark. This suggests that for the storage stability of fried products, the flour storage time is a more important factor than Aw at which the flour is stored.