Oxidative stability, trans,trans-2,4-decadienals, and tocopherol contents during storage of dough fried in soybean oil with added medium-chain triacylglycerols (MCT)

The lipid oxidative stability, trans,trans-2,4-decadienals, and tocopherols content of dough fried in soybean oil with added medium-chain triacylglycerols (MCT) during storage in the dark were investigated. Flour dough was fried at 100 °C for 5 min in a mixture of MCT and soybean oil at a volume ratio of 0% (0:100), 20% (20:80), 30% (30:70), and 40% (40:60). Fried dough was stored in a glass bottle at 50 °C in the dark for 12 days. The peroxide value was slight with 30% and 40% MCT oils for 12 days. In contrast, 10% and 20% MCT oils significantly increased the peroxide value. The lowest concentration of trans,trans-2,4-decadienal in soybean oil with added MCT. Fried dough in soybean oil with added MCT during storage in the dark was significantly increased in 0% MCT and 10% MCT. In contrast, the lowest concentration of trans,trans-2,4-decadienal in soybean oil with added 30% MCT and 40% MCT. Total tocopherols in 0% MCT oil were degraded 79.5% in 12 days at 100 °C. In contrast, 40% MCT oil significantly decreased the rate of degradation. The ratio of unsaturated fatty acids to saturated fatty acids (U/S ratio) decreased and hydroperoxide content increased with storage time. U/S ratio and hydroperoxide and tocopherol contents were lower in dough fried in soybean oil with added MCT than in dough fried in 100% soybean oil, indicating decreased lipid oxidation.