Valorization of grape pomace: Extraction of bioactive phenolics with antioxidant properties

Influence of pH and ionic strength on the color parameters and antioxidant properties of an ethanolic red grape marc extract

“…The obtained values for antioxidant activity (ORAC) and total polyphenols comprised between 906 and 2,337 μmol TE/g, respectively, and 142.4 ± 1.1 mg GAE/g of dry pomace, which are higher than the ones obtained in this study. The results of the HPLC analysis revealed the presence of gallic acid, caffeic acid, (+) catechin, syringic acid, and (−) catechin, the latter two being the major compounds (Tournmour et al, ). Different results may be explained by the fact that the marc was obtained from different grape varieties and has resulted from different winemaking techniques (Apolinar‐Valiente, Romero‐Cascales, Gomez‐Plaza, Lopez‐Roca, & Ros‐Garcia, ).…”

“…The obtained values for antioxidant activity (ORAC) and total polyphenols comprised between 906 and 2,337 μmol TE/g, respectively, and 142.4 ± 1.1 mg GAE/g of dry pomace, which are higher than the ones obtained in this study. The results of the HPLC analysis revealed the presence of gallic acid, caffeic acid, (+) catechin, syringic acid, and (−) catechin, the latter two being the major compounds (Tournmour et al, 2015).…”

“…Negro, Tommasi, and Miceli (2003) have obtained the values 4.19 g/100 g for polyphenols, 3.94 g/100 g for flavonoids, and 0.98 g/100 g for anthocyanins, all the results being expressed as With regard to specific phenolics, gallic acid, procyanidins B1 and B2, catechin, epicatechin, ferulic acid methyl ester, hyperoside, polydatin, ferulic, chlorogenic, and salicylic acids were the main compounds found in the grape marc extract. Tournmour et al (2015) analyzed grape pomace from Portuguese cultivars. The obtained values for antioxidant activity (ORAC) and total polyphenols comprised between 906 and 2,337 μmol TE/g, respectively, and 142.4 ± 1.1 mg GAE/g of dry pomace, which are higher than the ones obtained in this study.…”

Grape and Apple Pomaces from Southern Brazil: Valorization of By-Products through Investigation of Their Antioxidant Potential

“…32 Farhadi et al 22 studied different cultivars, species and parts of grapes (seed, skin, peel and pulp) and identified other compounds with antioxidant capacities beyond those found in this work, particularly catechin, epicatechin, quercetin and rutin flavonoids. Tournour et al 8 conducted comparative studies of different varieties of Portuguese grapes using different methods of extraction, and their studies have revealed the presence of gallic acid, caffeic acid, syringic acid, catechin and epicatechin, and the major compounds were syringic acid and catechin.…”

“…2 Grapes, apples, their derivatives and by-products are considered source of antioxidant activity compounds because they have a high content of phenolic compounds as phenolic acids, several flavonoids, monomers (catechin, epicatechin and gallocatechin) and superior phenolic (proanthocyanidins or condensed tannins). 3,[5][6][7][8] When processing grapes and apples to produce wine, juice and jams, significant amount of waste is generated (peel, seeds, pulp and stems). It is estimated that only 20% of fruit weight is used and the remaining is discarded 9,10 as animal feed and to make compost, destinations that do not generate economic gains for agribusiness and represent problems for disposal.…”