Grape water: reclaim and nutraceutical potential of a by-product from the industrial cryoconcentration of grape (Vitis vinifera L.) must.

The term “grape water” refers to a by-product from the cryoconcentration of grape (Vitis vinifera L.) must, conventionally treated as wastewater. Aim of this study was to evaluate the nutraceutical potential of pasteurized waters, reclaimed from the cryoconcentration of organic Grillo and Moscato grapes musts. Aside from pH, physicochemical parameters, such as conductivity, hardness and fixed point, were in agreement with Italian regulation for drinking waters. The elemental analysis was carried out by means of ICP-MS: both waters showed interesting levels of F- (3.02-8.02 mg L-1) and SO4- (52.85-49.34 mg L-1), a very low Na content, and valuable Mg (5.54-7.78 mg L-1), K (47.12-59.87 mg L-1), Fe (219.09-205.32 µg L-1), and Zn (189.65-127.30 µg L-1) amounts. Through GC-FID, the free fatty acid distribution was determined, with palmitic, oleic and linoleic acids as major components, higher in Moscato than in Grillo samples (27.71% vs. 21.90%, 64.42% vs. 58.22%, and 5.42% vs. 6.07%, respectively). A rich aromatic fingerprint was revealed by means of HS-SPME-GC-(MS/FID) in both the two types of water samples; linalool and a-terpineol were predominant in Moscato water, whereas hexanol, cis-rose oxide, and linalyl acetate in Grillo water. A moderate antioxidant activity, attributed to the presence of specific elements and of polyphenols (total amount <35 mg GAE L-1), was observed in all samples by means of the DPPH free radical-scavenging assay. Statistical analysis (two-tailed Student’s t-test) was applied to the whole set of analyses.