RADICAL SCAVENGING CAPACITY OF ETHYLENE-TREATED KIWIFRUIT

Abstract

ABSTRACT The aim of this investigation was to compare the content of the polyphenols and ascorbic acid and the radical scavenging capacity of ethylene-treated and nontreated kiwifruit. It was found that the contents of these bioactive compounds determined by UV spectroscopy and fluorometry were higher in ethylene-treated kiwifruit than in the nontreated ones. In order to support the obtained data, two different antioxidant assays were used. Antioxidant capacity in total polyphenol extracts of treated kiwifruit measured by ferric-reducing/antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays were significantly higher than that of nontreated. Higher correlation coefficients were obtained with polyphenols and antioxidant activity than with ascorbic acid. FRAP produced the most consistent measurements for ethylene-treated kiwifruit. The investigated samples showed similar protein bands during the whole period of treatment. Main protein bands appeared in the range of 20–35 kDa. The radical scavenging capacity of the kiwifruit can be used for the determination of the ripening. PRACTICAL APPLICATIONS It is an established fact that supplementation of diet with fruits prevents atherosclerosis and other diseases. A new method was developed and applied for estimation of the duration of kiwifruit ethylene treatment, which is based on the comparison of the radical scavenging capacity and polyphenols in treated and nontreated fruits. Radical scavenging capacity can be determined by different antioxidant tests, which makes such application easy to use practically. The results of this research showed that the bioactivity of kiwifruit increased during the ethylene treatment and its maximum was registered at the sixth day. This is the maximum of the treatment of the fruit, and the bioactive compounds achieved the peak amounts. The main bioactive compounds in kiwifruit with high antioxidant activity prevent the oxidation of low density cholesterol, and can be recommended as a supplementation to the diet and as a part in functional foods.