Anthocyanin Recovery from Grape by-Products by Combining Ohmic Heating with Food-Grade Solvents: Phenolic Composition, Antioxidant, and Antimicrobial Properties.

Marta Coelho,António Sebastião Rodrigues,Eduardo Costa,José António Teixeira,Sara Silva,Manuela Pintado,Ricardo N Pereira

doi:10.3390/molecules26133838

Marta Coelho, António Sebastião Rodrigues + Show 5 more

Open Access

https://doi.org/10.3390/molecules26133838

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Abstract

Usually, wine-making by-products are discarded, presenting a significant environmental impact. However, they can be used as a source of bioactive compounds. Moreover, consumers’ increasing demand for naturally nutritious and healthy products requires new formulations and food product improvement, together with sustainable, environmentally friendly extraction methods. Thus, this work aimed to compare ohmic heating (OH) with conventional methodology (CONV), using food-grade solvents, mainly water, compared to standard methanol extraction of anthocyanins. No significant differences were found between the CONV and OH for total phenolic compounds, which were 2.84 ± 0.037 and 3.28 ± 0.46 mg/g DW gallic acid equivalent, respectively. The same tendency was found for antioxidant capacity, where CONV and OH presented values of 2.02 ± 0.007 g/100 g and 2.34 ± 0.066 g/100 g ascorbic acid equivalent, respectively. The major anthocyanins identified were malvidin-3-O-acetylglucoside, delphinidin-3-O-glucoside, petunidine-3-O-glucoside, cyanidin-3-O-glucoside, and peonidine-3-O-glucoside. These extracts displayed antimicrobial potential against microorganisms such as Yersinia enterocolitica, Pseudomonas aeruginosa, Salmonella enteritidis, methicillin-sensitive Staphylococcus aureus, a methicillin-resistant Staph. aureus (MRSA), and Bacillus cereus. In conclusion, OH provides similar recovery yields with reduced treatment times, less energy consumption, and no need for organic solvents (green extraction routes). Thus, OH combined with water and citric acid allows a safe anthocyanin extraction from grape by-products, thus avoiding the use of toxic solvents such as methanol, and with high biological potential, including antimicrobial and antioxidant activity.

Highlights

(TPC) (Figure (Figure 1), 1), aa better better recovery recovery yield yield was was ning obtained with MeOH acidified in all extraction methods oh ith
The malvidin-3-O-glucoside is the corroborated by results from antioxidant analysis measured by ABTS, where citric acid ly, with OH extraction. These results presented are corroborated by results from antioxidant analysis measured by ABTS, where citric acid corroborated by results from antioxidant analysis measured by ABTS, where citric acid main anthocyanin present for all extracts (Table and showed the highest values of antioxidant capacity (AA)
The present study assessed the recovery of anthocyanins based on thermal and solvent treatments of grape by-products by OH, control positive (CP), and CT extraction methods

Summary

Introduction

The wine-making process produces a large number of by-products that have a significant environmental impact This process generates a high amount of solid organic waste, namely stalks, pomace (including skins, seeds, grape pulp l) and lees, which may be disposed of or beneficial use [1,2]. These by-products can be used as a source of bioactive compounds, such as dietary fiber, grape seed oil, hydrocolloids, and phenolic compounds, which might be applied by the agri-food and feed industries promoting economic value. Strategies for smart, sustainable, and inclusive growth must be adopted, promoting environmental protection [3,4,5]

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