Simultaneous extraction of tocochromanols and flavan-3-ols from the grape seeds: Analytical and industrial aspects

• Published in: Food chemistry Vol. 462; p. 140913
• Main Authors: Górnaś, Paweł, Mišina, Inga, Waśkiewicz, Agnieszka, Perkons, Ingus, Pugajeva, Iveta, Segliņa, Dalija
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2025
• Subjects: Antioxidants - chemistry; Antioxidants - isolation & purification; Aqueous ethanol solutions; Co-extraction; Extractability; Flavonoids - analysis; Flavonoids - chemistry; Flavonoids - isolation & purification; Phytochemicals; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Seeds - chemistry; Sustainable approach; Tocopherols - analysis; Tocopherols - chemistry; Tocopherols - isolation & purification; Tocotrienols; Tocotrienols - analysis; Tocotrienols - chemistry; Tocotrienols - isolation & purification; Vitaceae; Vitis - chemistry; Phytochemicals; Extractability; T; Co-extraction; UAE; Vitaceae; Sustainable approach; Tocotrienols; Aqueous ethanol solutions; T3
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2024.140913

Grape processing generates large amounts of by-products, including seeds rich in hydrophilic and lipophilic antioxidants. This study demonstrates, for the first time, that subjecting grape seeds to a single ultrasound-assisted extraction (UAE) with aqueous ethanolic solutions yields both flavan-3-ols and tocochromanols in the final extract. Notably, the water content in ethanol significantly influences the extractability of tocochromanols more than flavan-3-ols. Solid-to-solvent ratios of 1:50 to 1:2 were tested for both analytical and industrial applications. A sustainable analytical approach for recovering flavan-3-ols and tocochromanols using 60% and 96.4% ethanol extractions was validated and employed to profile nineteen genotypes of lesser-studied interspecific grape crosses (Vitis spp.). Different genotypes showed a wide range of concentrations of tocopherols (1.6–6.3 mg/100 g), tocotrienols (1.0–17.4 mg/100 g), and flavan-3-ols (861–9994 mg/100 g). This indicated that the genetic background and maturity of the plant material are crucial factors from an industrial perspective due to the initial concentration of bioactive compounds. Finally, the study also discussed the fundamental aspects of hydrophobic antioxidant extractability from the lipid matrix with aqueous ethanol solutions and the limitations of the workflow, such as the non-extractable tocochromanols and their esters and the losses of these lipophilic antioxidants during extraction. [Display omitted] •Seeds of grape crosses (Vitis spp.) consist of diverse phytochemical profiles.•Sustainable water-ethanol methods for phytochemical extraction were proposed.•Tocochromanols are co-extractable during the flavan-3-ols recovery from grape seeds.•Solid-to-solvent ratios 1:50 and 1:2 tested for analytical and industry applications.•The presence of non-extractable and bound tocochromanols in grape seeds was studied.