Production of grape pomace extracts with enhanced antioxidant and prebiotic activities through solid-state fermentation by Aspergillus niger and Aspergillus oryzae

MEINI, M. R.; CABEZUDO, I.; GALETTO, C.; ROMANINI, D.

Food bioscience

Elsevier

Año: 2021

2212-4292

Grapepomace is a winery by-product that accumulates in high amounts in winemakingindustry, which usually found difficulties regarding its disposal. Nonetheless,it has a great proportion of polyphenols which can be recovered to valorisethis biomass. Filamentous fungi produce hydrolytic enzymes, which can assist inthe liberation of polyphenols. Grape pomace was fermented in solid-state by Aspergillus niger and Aspergillus oryzae with the aim offacilitating the aqueous extraction of polyphenols with antioxidant activity byon-site enzyme production. Both fungi increased the antioxidant activity of theextracts, reaching maximum values of 73.7 ± 0.8 (A. niger) and 109.2 ± 0.5 (A.oryzae) mmol of Trolox equivalents/100 g of grape pomace. Duringfermentations, relevant enzymes were produced at high yields, A. niger produced a balanced profile ofenzymes (cellulase, tannase, and pectinase), while A. oryzae switches to cellulase or tannase selective inductionaccording to the fermentation conditions. Positive correlations were foundbetween enzyme production, polyphenols recovery, and antioxidant activity. Theextracts obtained after fermentation promoted the growth of Lactobacillus casei cultures. Therefore,the solid-state fermentation was effective for the simultaneous production ofrelevant industrial enzymes and grape pomace extracts with antioxidant andprebiotic properties, which have potential as functional food additives.