Phenolic compounds profiling in Ahmar Bou-Amar grapes extracted using two statistically optimized extraction methods.

This research revolutionizes phenolic compound extraction from grape pulp (Ahmar Bou-Amar variety). We optimized extraction methods to assess the efficiency and identify individual molecules. Response Surface Methodology (RSM) was employed to fine-tune 2 extraction methods: Conventional Solvent Extraction (CSE) and microwave-assisted extraction (MAE) using Box-Behnken and central composite designs, respectively. Identification and quantification of the various phenolic classes in the pulp of the studied grape variety were carried out using HPLC–DAD, a first for this variety. This characterization revealed that the quantitative profile of individual and total phenolic compounds is closely linked to the extraction method. Results indicate that extracts obtained via MAE exhibit approximately 20% higher concentrations of individual flavonols (Quercetol 3-glucoside, Quercetol-hexoside, Isorhamnitol-hexoside), individual hydroxycinnamic acids (cis- and trans-Caftaric, cis- and trans-Coutaric, p-Coumaric), and flavan-3-ols (trans-Catechin-SH and Epicatechin-3-O-gallate) compared to CSE. Conversely, CSE proves more efficient in extracting molecules like Catechin, Epicatechin, cis-Catechine-SH, and Ferulic acid, resulting in reductions of 16%, 21%, 75%, and 57%, respectively. Notably, the molecules Epicatechin-SH, Epicatechin-O-3-gallate, and Epigallocatechin-SH remain unaffected by the extraction method. The results concerning antioxidant activity indicate that irrespective of the measurement method employed, extracts obtained via MAE display notably greater antioxidant efficacy compared to those obtained through CSE. These findings underscore the significant impact of the chosen extraction method on the composition and quality of phenolic extracts obtained from grape pulp. [ABSTRACT FROM AUTHOR]