Anthocyanin composition and extraction from Grenache noir ( Vitis vinifera L.) vine leaf using an experimental design. I - By ethanol or sulfur dioxide

摘要

Aim: Anthocyanins are water soluble pigments mainly located in grape skin; however, these phenolic compounds are also located in vine leaves. The aim of this work was to identify, quantify and determine for the first time the anthocyanin composition in Grenache noir (Vitis vinifera) leaves.Methods and results: Five anthocyanins were identified and quantified in Grenache noir leaves by HPLC-UV-MS. Of these, cyanidin-3-O-glucoside and peonidin-3-O-glucoside were the main anthocyanins and represented 44 and 37%, respectively, while delphinidin-3-O-glucoside, petunidin-3-O-glucoside and malvidin-3-O-glucoside accounted for only 6, 5 and 8%, respectively. A multi-factorial design experiment was used to build a mathematical model to estimate the best extraction condition (highest anthocyanin extraction yield from leaf extract) for both SO2 and ethanol in the aqueous extraction solvent. For SO2, the optimal extraction parameters were an extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO2 in the aqueous extraction solvent. Using the hydro-alcoholic extraction solvent, the optimal extraction parameters were an extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration in the extraction solvent ranging between 32 and 40%.Conclusion: Only the five mono-glucoside anthocyanins usually detected in grapes have been detected, indentified and quantified in Grenache noir leaves by HPLC-UV-MS. Using a multi-factorial design experiment the optimum conditions for the extraction of these anthocyanins were obtained in hydro-alcoholic solution (i.e., extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration ranging between 32 and 40%) and in water with SO2 (i.e., extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO2 in water).Significance and impact of the study: Five anthocyanins were detected, identified and quantified in Grenache noir leaves by HPLC-UV-MS and the main anthocyanin were with cyanidin-3-O-glucoside and peonidin-3-O-glucoside. The.