Autohydrolysis Application on Vine Shoots and Grape Stalks to Obtain Extracts Enriched in Xylo-Oligosaccharides and Phenolic Compounds

Agronomic practices and the winemaking process lead to the production of considerable quantities of waste and by-products. These are often considered waste with negative effects on environmental sustainability. However, vine shoots and grape stalks can be reused, representing a potential source of xylo-oligosaccharides and polyphenols. In this context, the purpose of this work was to obtain enriched extracts using three different autohydrolysis treatments with (i) H2O, (ii) H2O:EtOH, and (iii) H2O:Amberlyst. The obtained extracts were characterized by their xylo-oligosaccharide and polyphenol profiles using LC-MS techniques. The use of ethanol during autohydrolysis allowed for greater extraction of xylan-class compounds, especially in vine shoot samples, while an increase in antioxidant activity (128.04 and 425.66 mu mol TE/g for ABTS and DPPH, respectively) and in total phenol content (90.92 mg GAE/g) was obtained for grape stalks.

Automated summary

Agronomic practices and winemaking processes generate a significant amount of waste and by-products, which are usually seen as environmentally unsustainable. However, vine shoots and grape stalks can be reused to obtain xylo-oligosaccharides and polyphenols. This study examined three different autohydrolysis treatments using water, water:ethanol, and water:Amberlyst to extract enriched extracts. Ethanol enhanced the extraction of xylan-class compounds, especially in vine shoot samples, while grape stalks showed increased antioxidant activity (128.04 and 425.66 mu mol TE/g for ABTS and DPPH) and total phenol content (90.92 mg GAE/g).