Semi-industrial ultrasound-assisted extraction of grape-seed proteins.

BACKGROUND: Handling grape-seeds, an abundant by-product of the wine-making process, is essential for managing industrial waste in accordance with the circular bioeconomy concept. An ultrasound-technology-based scaling-up process for the extraction of grape-seed proteins, due to their nutritional and techno-functional properties, is therefore presented herein. The protein contents of the extracts obtained under silent and on lab and semi-industrial ultrasound conditions have been compared, and the chemical composition (carbohydrates, total phenols and lipids) and elemental profile of the final, up-scaled downstream extract have been characterized.

RESULTS: The findings of the present work showed that the maximum protein amount in the final product was 378.31 g.kg-1 of extract. The chemical characterization revealed that each 1 kg of extract had an average content of 326.19 g gallic acid equivalents as total phenols, 162.57 g glucose equivalents as carbohydrates and 382.76 g of lipophilic compounds. Furthermore, when the extract was checked for hazardous elements, none were found in levels that could be considered a risk for human health.

CONCLUSION: The proposed semi-industrial strategy has the potential to greatly contribute to the valorisation of grape-seeds through the preparation of a protein-rich extract that can be used as an alternative to synthetic wine stabilizers and for the development of novel food and nutraceutical products. This article is protected by copyright. All rights reserved.