Phytochemical profile of Brazilian grapes (Vitis labrusca and hybrids) grown on different rootstocks.

Important factors may influence the bioactive compounds in grapes, including scion-rootstock interaction. Therefore, the bioactive compounds and antioxidant activity in grape skin and pulp fractions of 'Isabel Precoce', 'BRS Carmem', 'BRS Cora', 'BRS Violeta' and 'IAC 138-22 Máximo' were assessed. These cultivars, from genetic improvement programs in Brazil, have good adaptation to subtropical and tropical climate conditions, and can be widely used by winegrowers aiming at adding value to the grape. All grapevines were grafted onto 'IAC 766' and 'IAC 572' rootstocks under tropical conditions in Brazil. The highest concentration of bioactive compounds was found in skins of 'BRS Violeta', followed by 'IAC 138-22 Máximo', both grafted onto 'IAC 766'. There was a strong correlation between phenolic content and antioxidant properties, since antioxidant activity also decreased in the sequence: 'BRS Violeta' > 'IAC 138-22 Máximo' > 'BRS Cora' > 'BRS Carmem' > 'Isabel Precoce'. Skin from hybrid grapes ('BRS Violeta', 'IAC 138-22 Máximo', 'BRS Cora' and 'BRS Carmem') grafted in both rootstocks contains higher levels of (poly)phenolic compounds and antioxidant activity than 'Isabel Precoce' (V. labrusca). Skin from 'BRS Violeta' grafted onto 'IAC 766' stand out from the others due to their high content of bioactive compounds.

New trends in the use of enzymes for the recovery of polyphenols in grape byproducts.

Residues from wine and juice processing still contain about 70% of the phenolic compounds in grapes. These compounds are valued for having several bioactive properties that are explored in the pharmaceutical and food sectors. This paper aims to summarize the most recent advances in the use of enzymatic techniques for the recovery of bioactive compounds from GP for industrial application. For this, we analyzed scientific articles and patent applications from the last 20 years in the main indexed and patent databases. Among the most used enzymes in the recovery of bioactive compounds in wastes, cellulases, pectinases, tannases, glucoamylases, and proteases such as trypsin and chymotrypsin, are the most important. As a result, extracts are obtained with greater retrieval of compounds such as anthocyanins, gallic acid, catechins, epicatechins, and trans-resveratrol and the improvement of coloring, anti-inflammatory, antioxidant and vasoprotective properties. Although the use of enzymes for the recovery of phenolics is an old strategy, the number of studies focusing on the functional characteristics and industrial applicability of the extracts obtained has been recently growing. PRACTICAL APPLICATIONS: Phenolic compounds have acted as anti-inflammatories, antioxidants, anticarcinogens, and antimicrobials, being additives or relevant ingredients for various products in the food and pharmaceutical industry. Although there are several techniques for extracting/recovering phenolics from grape pomace, there is still no agreement on which method is ideal. In recent years, several extractions methods have been applied in seeking optimized conditions to recover phenolics from grape residues. Among them, the use of enzymes has been gaining attention for being considered a green and promising technology. The present study aims to carry out a review that would bring a new perspective to the recovery of bioactive compounds from grape residues by enzymatic techniques, with a view to industrial purpose.

Rapid determination of flavonoids and phenolic acids in grape juices and wines by RP-HPLC/DAD: Method validation and characterization of commercial products of the new Brazilian varieties of grape.

A method for rapid determination of phenolic compounds by reversed-phase high-performance liquid chromatography (RP-HPLC), using a new column of faster resolution was validated and used to characterize commercial products produced with new grape Brazilian varieties of Northeast of Brazil. The in vitro antioxidant activity was also measured. The method showed linearity (R>0.9995), good precision (CV%<2.78), recovery (91.8-105.1%) and limits of detection (0.04-0.85mgL-1) and quantification (0.04-1.41mgL-1) according to other methods previously published with the difference of a run time of only 25min. The results obtained in the characterization of the samples differed for juices and wines from other world regions, mainly because of the high values of (-)-epigallocatechin and trans-caftaric acid. The products analyzed showed high antioxidant activity, especially the wine samples with values higher than those from wines of different regions of the world.