Waste grape skins thermal dehydration: potential release of colour, phenolic and aroma compounds into wine

Polyphenolic Profile of Red Wines for the Discrimination of Controlled Designation of Origin

“…Phenolic compounds contribute to astringency and bitterness, which are produced mainly by flavonoids from the skins and seeds of grape (Basha et al 2005;Lutz et al 2012). Consumers are demanding functional foods, as wine with high characteristics, as colour, body, soft tannins (Boggia et al 2013;Pedroza et al 2012) and high content in polyphenols with high antioxidant activity (Crupi et al 2013). The red wine is a rich source of polyphenols that contribute to antioxidant activity and sensorial characteristics (Melendez et al 2013;Toaldo et al 2013).…”

Influence of Temperature and Drying Time on Extraction Yield of Phenolic Compounds from Grape Pomace Variety “Portogizac”

“…Otherwise, convection drying based on heated air in different designed drying devices (cabinet driers, tunnel driers, fluid-bed driers), vacuum drying, freeze-drying, and alternative methods, such as infrared drying and microwave drying, ensure better process control, shelf-stability and microbiologically safe dried product, with minimal degradation of nutrients and sensory quality 21,22 . Several studies have investigated the effects of different drying methods on the recovery of phenolic compounds from grape pomace [32][33][34][35][36][37] . These studies have compared conventional hot air or vacuum drying with freeze-drying as a more effective drying method for by-products where material is not exposed to high temperatures resulting with preservation of organoleptic and nutritive properties of the products.…”

Pre-bottling use of dehydrated waste grape skins to improve colour, phenolic and aroma composition of red wines

“…Such changes are particularly important for red wines because colour is an important quality parameter that may influence consumer preferences (Parpinello, Versari, Chinnici, & Galassi, 2009). Previous work on dehydration and characterization of waste grape skins from the juice industry (Pedroza et al, 2012) and extraction conditions in wine model solution and white wines (Pedroza et al, 2011) pointed out favourable parameters for releasing colour, polyphenols and aroma compounds. These works also suggested that the use of DWGS mixtures could be studied in order to fit the needs of certain types of wines like those having colour loss before bottling.…”

“…Samples obtained immediately after pressing the macerated must were collected in plastic bags (60 kg) and frozen at À20°C. In the laboratory, waste grape marcs were thawed at 25°C and oven dried at 60°C, according to Pedroza, Carmona, Pardo, Salinas, and Zalacain (2012) until a constant weight was achieved (3-5% moisture content). Dried samples were sieved through 3 mm mesh to remove seed and stalks.…”