Effects of Seed Coat on Oxidative Stability and Antioxidant Activity of Apricot (Prunus armeniaca L.) Kernel Oil at Different Roasting Temperatures

Apricot kernels were roasted at various temperatures (120-180 degrees C) for 10 min and changes in the fatty-acid profiles, oxidative stability, and antioxidant activity, as well as the total phenolic contents (TPC) of the oils and skin (seed coat), were monitored. Roasting has no obvious influence on profiles and contents of fatty acid, induction period (IP), browning index, TPC, and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), (ABTS) and Oxygen Radical Absorbance Capacity (ORAC) of oils obtained from apricot naked-kernel, but increases IP, TPC, and oxidative stability in oils obtained from apricot kernel with skin. All results in the present work demonstrated that thermal treatment accelerated the production and transference of alcohol-soluble phenolics into the oil, and improved the oil oxidative stability. It is not Maillard reaction products but alcohol-soluble phenolic compounds in skins that play a role in improving the oxidative stability and antioxidant activity of oils, and inhibition for primary peroxide production was more effective than secondary peroxide production at a low roasting temperature and a short roasting time. The present findings can advance knowledge on the conditions used for utilization of coproducts (skin) of apricot kernel and facilitate large-scale production of stable oil against oxidation.