OZONE-INDUCED CHANGES IN PHENOLS AND ANTIOXIDANT CAPACITIES OF PEANUT SKINS

Changes of total phenols, flavonoids, proanthocyanidins and antioxidant capacities of peanut skins were studied after they were ozonated for different times (0-60h). The phenols and their oxidation products in peanut skins were identified by High Performance Liquid Chromatography Coupled Quadrupole Time-of-Flight Mass Spectrometry (HPLC-Q-TOF/MS). Ozone treatment significantly affected total phenolic and proanthocyanidin contents, which were reduced by 48.77 and 47.71% after 24h of ozone treatment, respectively. Total flavonoids were increased due to new flavonoids formed during ozone treatment. The antioxidant capacities of peanut skin extracts were closely correlated to the total phenolic and proanthocyanidin contents, and the correlation coefficients (R) were 0.9831 and 0.7859, respectively. The decrease of total phenolic and proanthocyanidin contents reduced obviously the antioxidant capacities of peanut skin extracts. Ten phenolic compounds and seven oxidation products were identified by Q-TOF/MS, and the changes of their peak areas further verified the changes of phenols in peanut skin extracts at different ozonation times. Practical ApplicationsMany studies have proved that ozone can degrade aflatoxins in peanuts. However, ozone treatment can also affect the phenols in peanut skins, and then influence their antioxidant capacities. This study demonstrated the changes of phenols and their antioxidant capacities in the ozonated peanut skins. The phenolic compounds and their oxidation products were identified by TOF/MS. Information on the changes of phenols induced by ozone would help in improving the detoxification technology of peanuts for maintaining more functional components in peanut skins.