New Insights into the Effects of Sugars and Cultivars on the Mass Transfer, Quality, and Health Properties of Osmotically Dehydrated Peach

Abstract

The effects of three osmotic agents (glucose, sorbitol and sucrose) and four cultivars of peach were analysed in osmotically dehydrated fruit slices followed by convective air drying (OD+D). A comprehensive analysis of mass transfer parameters, and organoleptic, nutritional and nutraceutical properties was conducted, which included, for the first time, mineral composition and antimicrobial and enzymatic inhibitory activities in peach OD+D slices. Osmotic pretreatment improved the inhibition of protease, α-amylase and α-amyloglucosidase activities and the contents of tannins, flavonoids, phenolics and calcium in the OD+D treatment compared with those in the fresh fruit. Thus, OD+D adds value to a natural product, rendering peach slices that can be used in industry or consumed as snacks, with a sugar content equivalent to or lower than that of other fruits. Moreover, higher antimicrobial capacity and metabolite and antioxidant capacity retention were observed in OD+D than in exclusively hot-air-dried fruits. Clustering analysis of the OD+D slices displayed that the samples were grouped on the basis of the cultivar but not by the osmotic agents used for pretreatment, which is in line with the results of the statistical analysis, which revealed that the color; antioxidant capacity; ascorbic acid, carotenoid, phenolic, and flavonoid, and protein contents; inhibition of α-amylase and protease activity; and bacterial growth of the OD+D samples were independent of the osmotic agents used. The results obtained demonstrate that the choice of cultivar is a key determinant of the properties of the resulting dehydrated peach and reveal new benefits of osmotic pretreatment prior to convective-drying.