The impact of distillation process on the chemical composition and potential prebiotic activity of different oligosaccharidic fractions extracted from grape seeds.

The study was designed to evaluate how the distillation process is able to affect the composition and bioactivity of oligosaccharides contained in the grape seeds. Different oligosaccharidic fractions have been extracted both before and after grape pomace distillation in order to valorize this by-product. A multistep solid-phase extraction approach (C-18 and carbograph cartridges) has been applied to purify and fractionate the oligosaccharidic compounds. Chemical characterization of the fractions was performed using a UPLC-ESI-MS method. Complex oligosaccharides consist principally of neutral oligosaccharides rich in arabinose and glucose. Then, the oligosaccharides contained in the different fractions as potential functional ingredients with prebiotic activity toward well-known probiotic bacteria, such as Lactobacillus acidophilus and Lactobacillus plantarum, were evaluated. Data showed how, in some combination, oligosaccharidic fractions obtained may be considered a novel "functional ingredient" with potential prebiotic activity mainly towards L. acidophilus.