Oxidation of fats and oils in instant noodles stored under various conditions

Changes in the peroxide value (PV) in instant noodles stored under various conditions were carefully analyzed to examine the oxidation of fat and oils in instant noodles and to evaluate the importance of the maximal 30 mequiv/kg PV standard value in the Food Sanitation Law in Japan from a food safety point of view. The changes in PV in instant noodles stored at 40 to 60C gradually increased and then rapidly increased after exceeding approximately 30 mequiv/kg, regardless of the oxidation temperature. This finding indicates that the PV standard value is meaningful for suppressing the oxidation-induced formation of toxic compounds. The relationships among PV, acid value (AV, amount of free fatty acid) and p-anisidine value (AnV, amount of secondary oxidized products in the oil) in oxidized instant noodles were investigated. There was no significant relationship between PV and AV, and AV and AnV. In contrast, there was a significant relationship between PV and AnV. These results indicate that PV measurements are useful for predicting the formation of toxic compounds, particularly the secondary oxidized products of the oil, and measurements of both PV and AV are very important to accurately determine food deterioration level.