Different tools to enhance grape and wine anthocyanin content

Résumé

Grapes and wines are one of the most important sources of anthocyanins in the nature. Anthocyanins play a key role in wine quality since they are the main responsible for the color of both red grapes and wines, influencing then on consumers' preferences. Moreover, numerous studies indicate the potential effect that this family of phenolic compounds may have due to their potential health benefits such as antioxidant activity, antiobesity and antidiabetic properties, cardiovascular protection, and chemoprevention and cancer protection. Anthocyanin content in grapes is in part genetically determined but many other aspects also contribute to the final anthocyanin profile, including climate or soil factors. Moreover, during winemaking these compounds are subjected to many changes, resulting in the formation of new pigments which will determine the final color of wines. Due to the important benefits of anthocyanins, some tools have been developed in order to increase their concentration in both grapes and wines. Some of the approaches have been established with the aim of promoting the primary synthesis of these compounds in the vineyard while others have targeted the extraction of anthocyanins in a later stage in the cellar. Among viticultural practices, some strategies have proven to be very promising, such as leaf removal or elicitors application, which have been able to increase the content of not only anthocyanins, but also of other phenolic compounds. On the other hand, cold maceration, enzymes and new technologies such as ultrasounds and pulsed electric fields (PEF) offer significant advantages in the extraction of anthocyanins and other polyphenols before oenological processing. In particular, as regards the speed of the process, the maceration of red wine can be shortened by up to three days. For these reasons, this work is structured as follows: First we revise the main anthocyanins found in grapes and wines. Secondly, we study several strategies to increase the anthocyanin synthesis by the grapevine. And finally, we discuss different technologies to improve anthocyanin extraction from grape skins during winemaking. © 2015 by Nova Science Publishers, Inc. All rights reserved.