Thermal degradation of grape marc polyphenols

• Published in: Food chemistry Vol. 159; pp. 361 - 366
• Main Authors: Sólyom, Katalin, Solá, Ruth, Cocero, María José, Mato, Rafael B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.09.2014; Elsevier
• Subjects: Anthocyanin; Anthocyanins - chemistry; Antioxidants; Antioxidants - chemistry; Biological and medical sciences; Byproducts; Cosmetics; Degradation kinetics; Food toxicology; Foods; Grape pomace; Grapes; Heating; Hot Temperature; Kinetics; Medical sciences; Non-isothermal heating; ORAC; pH differential method; Plant Extracts - chemistry; Polyphenols - chemistry; Thermal degradation; Toxicology; Vitis - chemistry; Waste Products - analysis; Wine - analysis; Wines; ORAC; Anthocyanin; Non-isothermal heating; Degradation kinetics; Grape pomace; pH differential method; Fruit; Antioxidant; Flavonoid; Micronutrient; Degradation; Polyphenol; Heating; Grape; Plant origin; Phenols; Pigments; pH; Proanthocyanidin; Kinetics
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.03.021

•Thermal treatments on enhanced polyphenol extraction degrades active compounds.•Antioxidant degradation was studied at 80–150°C of grape marc and filtered extract.•Anthocyanins (AC) follow first order degradation; total phenol content and ORAC not.•Degradation was 10 times faster in grape marc than in filtered extract.•90% of AC can be preserved in a pretreatment at 150°C, if no longer than 1min. Bioactive compounds of wine making by-products are of interest in food, cosmetics and pharmaceutical industries. Extraction of antioxidants under mild conditions is time-consuming, giving ground to the development of intensification processes where the operation at high temperature may deteriorate extract quality. This study examined thermal degradation of grape marc and its filtered extract (80, 100 and 150°C). The decrease in anthocyanin content was modelled under non-isothermal conditions by first order kinetics, using the Arrhenius equation. Simulated degradation under isothermal heating showed that the grape marc is more sensitive by one order of magnitude to heat than the filtered extract. This tendency was also confirmed by analyses of the total phenolic content and antioxidant activity. It is suggested that an optimal combination of temperature, treatment time and also raw material environment could be found in process intensification.