Enzymatic protein hydrolysates of a residue from grape by-products industry for winemaking application: influence of the starting material and hydrolysis time

Abstract

Large quantities of defatted grape seed meal (DGSM) are discarded annually in the grape pomace industry. This residue could be exploited as a new source of non-animal protein to improve the chemical and color stabilization of red wines from warm regions. Different protein hydrolysates have been characterized, considering two different variables in their obtaining: type of raw material (DGSM from white and red grape pomaces) and hydrolysis time (1 and 4 h). The protein content of the hydrolysates, their molecular weight distribution, color, amino acid and peptide composition, and antioxidant activity were evaluated. Products obtained were mainly influenced by the type of raw material, regardless of the hydrolysis time. Hydrolysates from red DGSM displayed a higher protein content (∼67.4%) and protein yield (∼28.9%), visually perceptible (ΔE*_ab > 3) lower lightness (∼23.3) and color intensity (∼13.2), and a greater variety of peptides related to red wine color stabilization. However, hydrolysates from white DGSM showed a higher amino acid content and antioxidant capacity (∼33.5 µmol TE/g, by DPPH; ∼3710.9 µmol TE/g, by ORAC). According to the results obtained, both red and white DGSM are susceptible starting materials to be selected as optimal for application in winemaking, fixing 1 h as hydrolysis time.

Keywords:

• Grape seed protein hydrolysates
• molecular weight distribution
• differential tristimulus colorimetry
• antioxidant peptides
• warm climate

REVIEWING EDITOR:

• Manuel Tejada
• University of Seville
• Spain

SUBJECTS:

• Food Chemistry
• Food Analysis
• Natural Products
• Environment & Resources

Acknowledgments

The authors thank the technical staff of the Biology Service (Servicios Generales de Investigación (SGI), Universidad de Sevilla. The authors also thank Alvinesa Natural Ingredients, S.A (Daimiel, Ciudad Real, Spain) for supplying the by-product samples.

Author contributions

Ana Belén Mora-Garrido: Investigation, Writing – original draft. M. Luisa Escudero-Gilete: Writing – original draft, Writing – review & editing, Funding acquisition. Francisco J. Heredia: Conceptualization, Supervision, Funding acquisition. María Jesús Cejudo-Bastante: Supervision, Writing - review & editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Additional information

Funding

This work was supported by the MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” under Grants PID2021-127126OB-C22 and PID2021-124964OB-C22.

Notes on contributors

Ana Belén Mora-Garrido

Ana Belén Mora-Garrido is a predoctoral student at the Department of Nutrition and Bromatology of the University of Seville, being part of the research group AGR-225 “Color and Food Quality”. The research line of her thesis deals with the use of by-products of the winemaking industry to improve the organoleptic qualities of wines produced in warm climates.