Chiang Mai Journal of Science

The oxidative stability of refined sunflower oil supplemented with edible wild mushroom, Pleurotus porrigens crude extract, its n-butanol fraction (n-BUT, from liquid-liquid partitioning), and semi-purified sub-fraction (SF) III and SFIV, were tested under accelerated storage conditions compared with BHA and a-tocopherol, by measuring their peroxide value, p-anisidine value, thiobarbituric acid-reactive substance, and iodine value. The total phenolic content (TPC), 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging and ferric reducing/antioxidant power (FRAP) were also evaluated. P. porrigens’ SFIII exhibited highest DPPH scavenging, while n-BUT showed highest FRAP; TPC was found highest in crude extract. Generally, BHA and a-tocopherol are more protective in stabilizing the sunflower oil. P. porrigens’ SFIII and SFIV had short-term protective effect in secondary oxidation for ½-year; whilst crude extract retarded secondary oxidation (TBARS value) and extend the shelf-life upon 1½-year. P. porrigens extracts did not show similar retardation of lipid oxidation in sunflower oil as compared to a-tocopherol and BHA at 200 ppm. However, the higher concentration of P. porrigens extracts that provided the protective effect in stabilizing sunflower oil can be further studied.