Phytonutrient content and oil quality of selected edible oils upon twelve months storage

Abstract

AbstractEdible oils contain naturally occurring phytonutrients and therefore exhibit numerous beneficial health effects. However, the phytonutrients tend to degrade in different extent with storage duration and temperature. In this study, the impact of storage conditions on the stability of phytonutrients, including vitamin E, carotenoid, phytosterols and squalene, and oil quality, including free fatty acids (FFA), peroxide value (PV), anisidine value (AV), and oxidative stability index (OSI) of red palm‐pressed mesocarp olein, palm olein, extra virgin olive oil, and sunflower oil were investigated. The oils were stored in three conditions, 23°C (with light and without light) and 35°C (without light). Results showed that the retention percentages of phytonutrients where in the range of 0%–100% for vitamin E, 51.24%–83.63% for carotenoid, 83.40%–100% for phytosterols and 27.94%–100% for squalene. Pearson correlation analysis between phytonutrients and oil quality of oils in different storage conditions showed that correlation coefficient values (r) were in the range of −1 to 0 for FFA, −1 to 0.22 for PV, −1 to 0.33 for AV, and −0.23 to 1 for OSI, implying that correlations between both variables are not in same direction. Degradation studies of phytonutrients using zero‐order kinetic model where optimum‐case conditions exhibited highest half‐life (t1/2) among the three conditions. In conclusion, storage conditions and synergistic effect affected the phytonutrients stability in the oils and oil quality in different extent. In general, storage at ambient temperature and dark condition contributed to the best phytonutrients retention and oil quality.