Sistema de produção e radiação UV-C na síntese de compostos bioativos em uvas (Vitis labrusca, cv. Concord) e seus sucos.

Abstract

The preoccupation about healthy eating leads to the search for foods which offer properties that goes beyond nurture, but also can provide potential health benefits the human body. Accompanying this tendency the consumer is increasingly value food produced in systems which establish a commitment to environmental preservation and the health, such as fruit cultivation in organic production systems. Addition to that, it is known that the application of UV-C after fruit harvest is able to induce plant defense mechanisms by stimulating secondary metabolism. Therefore, it is expected that radiation UV-C can act as an inducer of the synthesis and accumulation of bioactive molecules by changing the grape composition - from the conventional and organic systems production - and its juices, and their potential functional properties. Aim to increase of the bioactive compounds concentration in grapes and juices, treated the grape Vitis labrusca, cv. Concord, grown in the southwest of Paraná. After harvesting the grapes were separated into two batches, one group received UV-C radiation after harvest and the other was not treated (control) followed by three days storage at room temperature in the dark. These treatments was produced their grape juice in extractor. Physic-chemical analyses were realized in grapes and juices and also was realized the transcriptional expression of genes involved in the synthesis of these compounds in grapes. According to the results, can be verified that the post-harvest treatment UV-C promotes the induction of bioactive compounds in grapes, cv. Concord, mainly anthocyanins, resveratrol, flavonols and tannins, and these changes depend on the production system used in the grapes cultivation. Also, it was when is applicated UVC radiation occur the increase in the levels of secondary metabolic compounds that was associated to increased gene transcripts of the biosynthesis of phenolic compounds. This study also has shown that the juices from grapes, from organic system, showed similar levels of bioactive compounds to grape juice processed with the conventional system. The application of UV-C in grapes after harvest resulted in juices with higher content of bioactive compounds. However, this post-harvest treatment behaves differently in the synthesis of these compounds depending on the production system of the grape, that is, in the organic grapes the response may be correlated to equilibrium factor existing in cultivation.