Comparative extraction study of grape pomace bioactive compounds by submerged and solid‐state fermentation

Abstract

AbstractBACKGROUNDAbout 75% of the total grape production worldwide is destined for wine production. Many agro‐industrial wastes are derived from the various stages of wine production that are not usually used. The present study explores grape pomace from the winemaking industry as a fermentation substrate for the extraction of phenolic compounds through two fermentation systems, submerged and solid‐state fermentation, using Aspergillus niger GH1 as a biological model.RESULTSBoth fermentation systems showed polyphenolic compounds release. The highest values for polyphenol content extraction were through solid‐state fermentation without supplementation with 2.262 g L−1 of hydrolysable tannins (HT) and 3.684 g L−1 of condensates tannins (CT). For submerged fermentation, however, the best results were obtained in the non‐supplemented medium obtaining 0.182 g L−1 of HT and 0.198 g L−1 of CT. A kinetic fermentation under the best fermentation conditions was carried out. The enzymatic activities associated with the extractive process were demonstrated (tannase, ellagitannase, β‐glucosidase, xylanase, and α‐L‐arabinofuranosidase). Among the main compounds identified were hydroxycinnamic acids, anthocyanins, proanthocyanidins, catechins, hydroxybenzoic acids, and flavonols.CONCLUSIONGrape pomace constitutes a nutrient‐rich material that can be used as a fermentation substrate to extract bioactive compounds. A. niger GH1 was shown to be able to synthesize hydrolytic enzymes capable of degrading grape pomace to release polyphenolic compounds. This study reveals the effectiveness of both types of fermentation and the influence of fermentation parameters on the recovery of polyphenols and on the mechanisms involved in these bioprocesses, which stand out for being eco‐friendly alternatives for the recovery of compounds of industrial interest. © 2021 Society of Chemical Industry (SCI).