Changes in chemical composition and oxidative stability of cold-pressed oils obtained from by-product roasted berry seeds

This study aimed to determine the effect of seed roasting on compositional parameters and oxidative stability of cold-pressed blackcurrant, raspberry, chokeberry, and strawberry seed oils, with rapeseed oil as a control sample. Roasting seeds decreased the peroxide concentration by about 50%, while secondary oxidation products increased by 9%-91%. There were no significant differences in the fatty acid composition of the berry seed oils following roasting. 7%-27% and 2%-26% of tocochromanols and phytosterols respectively were lost after roasting. Roasting increased the thermo-oxidative stability of the berry seed oils by almost 40% (except chokeberry seed oil). No significant decrease in the compositional parameters or oxidative stability of roasted rapeseed oil was found, probably due to presence of canolol (327.60 mu g/g). Raspberry seed oil has similar oxidative stability to rapeseed oil, probably due to the high concentration of gamma-T, delta-T, and ellagic acid possessing high antioxidant activity.