Profile of bioactive compounds from grape pomace (Vitis vinifera and Vitis labrusca) by spectrophotometric, chromatographic and spectral analyses

• The Mix sample had the highest concentrations for phenolics and flavonoids content.
• The polyunsaturated fatty acids were predominant in all samples.
• For all samples it was possible to identify 13 different anthocyanins by HPLC–MS/MS.
• Infrared spectroscopic signals were used to identify aromatic compounds groups.

The aim of this study was to characterize grape pomace (GP) from winemaking byproducts of different grape samples (Cabernet Sauvignon—CS; Merlot—ME; Mix composed of 65% Bordeaux, 25% Isabel and 10% BRS Violet—MI and Terci—TE) with a view to exploiting its potential as a source of bioactive compounds and an alternative to the reuse of waste. Bioactive compounds such as individual phenolic compounds and polyunsaturated fatty acids (PUFA) were identified and quantified by spectrophotometric, chromatographic and spectral analyses. The sample of MI had the highest concentrations for total phenolic compounds and total flavonoids, while TE had the highest content for total monomeric anthocyanins. For all samples it was possible to identify 13 different anthocyanins by high performance liquid chromatography (HPLC) and mass spectrometry (MS). Moreover, the GP samples showed phenolic acids; flavan-3-ols such as catechin; flavonols such as quercetin, rutin and kaempferol; and stilbenes such as trans-resveratrol. Therefore, grape pomace can be considered a source for the recovery of phenolic compounds having antioxidant activity as well as a rich source of PUFA. Thus it can be used as an ingredient in the development of new food products, since it is suitable for human consumption, and a viable alternative both to adding nutritional value to food and to reduce environmental contamination.