Major Flavonoids in Grape Seeds and Skins:  Antioxidant Capacity of Catechin, Epicatechin, and Gallic Acid

Abstract

Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds.

Antioxidant activities of young apple polyphenols and its preservative effects on lipids and proteins in grass carp (Ctenopharyngodon idellus) fillets

“…In addition, soluble tannins are also responsible for the high water-soluble antioxidant properties (Homoki et al, 2016). Phlorizin, chlorogenic acid, and epicatechin, three phenolic compounds accounting for relatively high content in YAP, have been shown antioxidant potentials as well (Cai et al, 2013;Sato et al, 2011;Yilmaz & Toledo, 2004). All the methods used in this study showed a high reducing capacity for YAP, by which the oxyradicals could be scavenged.…”

Microbicidal Activity of Artificially Generated Hydroxyl Radicals

“…The advantage of this disinfection technique is that polyphenols are supposed to be safe for humans because they are edible compounds naturally occurring in fruits, vegetables, nuts, seeds, and flowers. In addition, since those polyphenolic compounds are noteworthy for its antioxidative activity [74,75], they might alleviate the oxidative damage in the tissue after the disinfection treatment. Therefore, it is expected that this disinfection technique is applicable to the fields of medical and food sanitation.…”

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

“…The following list gives an enumeration of all the measures or procedures investigated: Maturity, ripening and time of harvest [63,74,82,99,115,116,176,178,179,188,189,194] 58,112,142,162,181,191,196], differentiation in fractions [114,167,174], peeling [109,142,153,180], special pressing or extraction [2, 64,72,165], enzymatic treatment and maceration [51], irradiation [53,158,175,183], drying [8,102,132,152,159], sensory effects [51], germination [88], browning-blanching and polyphenoloxidase (PPO) activity [124], proveniences [8,12,63,107,110,112,…”