Changes in polyphenolic content and antioxidant activity after thermal treatments of grape seed extract and grape pomace

• Published in: European food research & technology Vol. 234; no. 1; pp. 147 - 155
• Main Authors: Chamorro, Susana, Goñi, Isabel, Viveros, Agustín, Hervert-Hernández, Deysy, Brenes, Agustín
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.01.2012; Springer; Springer Nature B.V
• Subjects: Acids; Agriculture; Analytical Chemistry; Antioxidants; Biological and medical sciences; Biotechnology; By products; Chemistry; Chemistry and Materials Science; Chromatography; Cocoa; Food; Food industries; Food Science; Forestry; Fruit and vegetable industries; Fruits; Functional foods & nutraceuticals; Fundamental and applied biological sciences. Psychology; Heat; Heat treatment; Liquid chromatography; Original Paper; Phenols; Polymerization; Polyphenols; Seeds; Sorghum; Studies; Temperature effects; Spain; Polyphenols; Heat treatment; Autoclave; Grape pomace; Antioxidant activity; Grape extract; Seeds; Fruit; Grape marc; Extract; Antioxidant; Polyphenol; Grape
• ISSN: 1438-2377; 1438-2385
• DOI: 10.1007/s00217-011-1621-7

This study was undertaken to investigate the effect of heat treatment on polyphenolic content and antioxidant activity in grape pomace (GP) and grape seed extract (GSE). GP and GSE were heat treated in a furnace or autoclaved at 100 °C for 15, 30 and 60 min. Structural modifications of the polyphenols during thermal processes were determined by HPLC–MS, and the antioxidant activity was determined by ABTS, DPPH and photochemiluminescence methods. In general, furnace thermal treatment of GSE and GP did not affect the total extractable polyphenols content, tannin content, procyanidin components and the antioxidant activity. Autoclave treatment caused an extensive hydrolysis of gallocatechin (70%), catechin (61%), epicatechin (65%), procyanidin B1 (75%) and procyanidin B2 (73%) in GSE, and an increase in gallic acid (71%), gallocatechin (100%) and epicatechin gallate (129%) in GP. Autoclave treatment did not affect the antioxidant activity of GSE or GP. It can be concluded that the effect of autoclave was more severe than furnace heat treatment modifying the phenolic profile in a different manner depending on the grape seed product used. These modifications were not related with changes in antioxidant activity.