Revalorization of residues from the industrial exhaustion of grape by-products

Description

Wine industry produces annually a large amount of grape pomace by-products whose bioactive compounds are extracted and exploited for different technological purposes. In order to verify the efficiency of the extraction, the monitoring of each stage of the industrial processing of grape pomace, not previously considered, was carried out. For that purpose, samples of all stages of the extraction process (grape pomace, grape seed, washing waters, and defatted grape seed flour), from two grape varieties (Air´en and Tempranillo) were considered. Attention was focused on the content of protein, lipid, fiber, ash, polyphenols, and antioxidant activity. The data obtained showed that considerable amounts of protein (around 10%), fiber (20%–30%), and non-extracted phenols remain in the by-products of each stage of processing. Therefore, industrial extraction should be optimized to recover greater amounts of components of interest to other industries such as the food or pharmaceutical industry. Finally, the antioxidant activity of these samples was tested by DPPH and ABTS, and a positive correlation was found between phenols and antioxidant activity.

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