Carotenoid Content and Antioxidant Activity of Organic and Conventional Grape Juice Processing Waste

Abstract

The grapes used in the wine and juice agribusinesses generate large amounts of solid wastes rich in bioactive compounds, which include its seeds. From this, solid waste can be extracted from an oil, and this process yields a residual material. Numerous studies have suggested that the cultivation method can influence the content of secondary metabolites in food. This study aimed to investigate the carotenoids content and the antioxidant activity of grape seeds cultivated by conventional and organic farming (Vitis labrusca) and their residues after oil processing. Color was measured by a colorimeter; carotenoide content by HPLC-UV and antioxidant activity by tow different methods. Organic residue and Organic Seed presented more saturated and lighter color parameters with a greater tendency toward yellow and brown colors (lower h*). Organic residue and Conventional Residue showed higher levels of total carotenoids, provitamin A, and antioxidant activity by one method. Conventional Residue exhibited higher antioxidant activity, as determined quantitatively and qualitatively by another method, and higher levels of carotenoids in the extract. The results from this study suggest that food produced by organic farming is not different and can present even lower levels of carotenoids than that produced through conventional methods. Keywords: Antioxidant potential, bioactive compounds, carotene, conventional, organic, Vitis vinifera.