Towards the Optimization of Microwave-Assisted Extraction and the Assessment of Chemical Profile, Antioxidant and Antimicrobial Activity of Wine Lees Extracts

Abstract

Wine lees, a sub-exploited byproduct of vinification, is considered a rich source of bioactive compounds, such as (poly)phenols, anthocyanins and tannins. Thus, the effective and rapid recovery of these biomolecules and the assessment of the bioactive properties of wine lees extracts is of utmost importance. Towards this direction, microwave-assisted extraction (MAE) factors (i.e., extraction time, microwave power and solvent/material ratio) were optimized using experimental design models in order to maximize the (poly)phenolic yield of the extracts. After optimizing the MAE process, the total phenolic content (TPC) as well as the antiradical, antioxidant and antimicrobial activity of the extracts were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed to investigate the chemical profile of wine lees extracts. Red varieties exhibited higher biological activity than white varieties. The geographical origin and fermentation stage were also considered as critical factors. The white variety Moschofilero presented the highest antioxidant, antiradical and antimicrobial activity, while Merlot and Agiorgitiko samples showed noteworthy activities among red varieties. Moreover, IR spectra confirmed the presence of sugars, amino acids, organic acids and aromatic compounds. Thus, an efficient, rapid and eco-friendly process was proposed for further valorization of wine lees extracts.

Optimization of Ultrasound- and Microwave-Assisted Extraction for the Determination of Phenolic Compounds in Peach Byproducts Using Experimental Design and Liquid Chromatography–Tandem Mass Spectrometry

“…Since the real values (X 1, X 2, X 3 ) of the extraction factors are expressed in different physical units (i.e., minutes, Celsius degrees, seconds, volume-to-weight), they were switched and normalized to coded dimensionless values (x 1 , x 2 , x 3 ) to provide unbiased and reliable results [ 52 ]. The real and normalized values of the extraction parameters for the DOE models of the two extraction techniques are presented in Table 4 .…”

Antiherpetic Activity of Taurisolo®, a Grape Pomace Polyphenolic Extract

“…From the literature, we know that grape extracts are endowed with antimicrobial activity against various microorganisms. This activity is due to a higher number of polyphenols found in grapes skin, seed, shoot, and stem [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. However, none of these studies have described a possible antiviral effect.…”

Investigating the potential of wine lees as a natural colorant and functional ingredient in jelly production

“…2 This steady demand in wine production has been accompanied by a notable surge in the production of winery byproducts, including grape pomace/marc (comprising skins, seeds, and stems) and lees. 3 The term 'wine lees' (WL) is used to describe the sediment that forms at the base of wine bottles after the completion of several winemaking procedures, such as fermentation, storage, racking, and filtration. 4 Wine lees constitute a complex mixture of yeast cells, insoluble carbohydrates, organic acids, ethanol, phenolic compounds, proteins, inorganic salts, and lignin, accounting for approximately 2-6% of the total wine produced and representing 14-25% of all waste generated in wineries.…”

“…Global wine production in 2022 was estimated to be approximately 260 million hectoliters 2 . This steady demand in wine production has been accompanied by a notable surge in the production of winery by‐products, including grape pomace/marc (comprising skins, seeds, and stems) and lees 3 . The term ‘wine lees’ (WL) is used to describe the sediment that forms at the base of wine bottles after the completion of several winemaking procedures, such as fermentation, storage, racking, and filtration 4 .…”