Bench-scale extraction of stilbenoids and other phenolics from stored grape canes (Vitis vinifera): Optimization process, chemical characterization, and potential protection against oxidative damage

Abstract

Dietary supplements have become the key to complement deficiencies in the occidental diet and therefore to reduce the incidence of oxidative stress related diseases. A bench-scale extraction procedure was studied to obtain a valuable product rich in phenolic compounds and antioxidant capacity from Pinot Noir grape cane enhanced by storage. Extraction solvent, cane-size, solid:liquid ratio, temperature, and extraction time, were systematically evaluated in order to obtain a natural functional product. Complete chemical characterization of a Pinot Noir grape cane extract produced under bench scale process is presented for the first time. Phenolic profiles of the extracts were characterized by HPLC-PDA-MS/MS and minerals by ICP-OES. Proteins, carbohydrates and lignins were also evaluated. The main phenolic compounds in the final product were stilbenoids, flavan-3-ols, procyanidins, and flavonols, with 6.53%, 4.84%, 2.11%, and 0.25%, respectively on a dry matter basis. Other chemical constituents were carbohydrates (27%), minerals (1%) and lignins (38.7%). The antioxidant capacity of the product was demonstrated using chemical assays (TEACABTS/CUPRAC and ORAC-FL) and endothelial cells model. The extract produced under the described bench scale process using grape cane enhanced by storage have a chemical composition and protecting capacities to be used in functional foods industry.