Actinidia (Mini kiwi) fruit quality in relation to summer cutting

Abstract

Recently, there has been a trend towards healthy food. Consumers are looking for products that have health-promoting properties in addition to their taste. Actinidia fruit, apart from being tasty, contains valuable macro and micronutrients, vitamins, polyphenols and pectins. Tested cultivar Sientiabrskaja belong to Actinidia arguta and cultivars Geneva, Issai and Ken’s Red to A. kolomitka. They well tolerate conditions of moderate climate with negative temperatures in winter. To improve fruit quality, an additional summer pruning of the plants was performed at the time of ripening. After the second additional cutting of Actinidia shoots, an increase in the content of N, P and K in fruit was observed. The additional pruning also had a beneficial effect on the change in fruit color. The fruits were darker, especially in the cultivars Geneva and Ken’s Red. This is related to the ripening of fruit and an increase in anthocyanin content. Additional summer pruning caused changes in the polyphenol content-the amount of phenolic acid and flavan-3 ols decreased, while the level of anthocyanins increased. The antioxidant capacity also increased as well as fruit size, dry matter, pectin and Soluble Solid Content (SSC) content. The acidity of the fruit also decreased which positively affects the taste of the fruit. The highest content of polyphenols and L-ascorbic acid was found in ‘Sientiabrskaja’ fruit; but the highest antioxidant activity (determined Free Radical Diphenylpicrylhydrazyl-DPPH•, ABTS•+ and Ferric Antioxidant Power-FRAP) was found in fruit with red skin coloring and anthocyanins-‘Issai’ and ‘Ken’s Red’.