Antioxidant dietary fibre recovery from Brazilian Pinot noir grape pomace.

ABSTRACT

Brazilian grape pomace was extracted in hot water, and a factorial experiment was used to evaluate polysaccharide recovery. The dependent variables were the temperature, particle size and solutesolvent ratio. Polysaccharide yields varied from 3% to 10%, and the highest sugar content was observed when extraction was carried out at 100 °C from finely sized particles (⩽249 µm) in a 112 solutesolvent ratio. The monosaccharide composition of extracts obtained from flours were, on average, RhaAraXylManGalGlcGalA in a 332213112019 M ratio, with varying GlcGalA ratios. (13)C NMR and HSQC spectra confirmed the presence of pectic- and glucose-based polysaccharides in the extracts. Phenolic compounds were found after pomace extraction, and catechin, gallic acid and epicatechin were the principal compounds identified. The extracts also had ABTS radical scavenging capacity (from 8.00 to 46.60 mMol Trolox/100 g pomace). These findings indicate that these grape pomace flours are rich in antioxidant dietary fibre and have a potential use as food ingredients.