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

Extraction of Bioactive Compounds from Wine Lees: A Systematic and Bibliometric Review

The extraction of bioactive compounds from wine lees involves a variety of methods, the selection of which is crucial to ensure optimal yields. This systematic review, following PRISMA guidelines and utilizing the Web of Science database, aimed to examine the current state of this field, providing insights for future investigations. The search employed strategies with truncation techniques and Boolean operators, followed by a three-step screening using well-defined eligibility criteria. A bibliometric analysis was conducted to identify authors, affiliations, countries/regions, and research trends. Thirty references were selected for analysis, with Spain standing out as the main source of research on the topic. The majority of studies (66%) focused on the extraction of bioactive compounds from alcoholic fermentation lees, while 33% were directed towards malolactic fermentation lees. Binary mixtures (ethanol-water) were the predominant solvents, with ultrasound being the most used extraction method (31.3%), providing the highest average yields (288.6%) for the various evaluated compounds, especially flavonoids. The potential of wine lees as a source of bioactive compounds is highlighted, along with the need for further research exploring alternative extraction technologies and the combination of methods. Additionally, the importance of "in vitro" and "in vivo" tests to assess the bioactive potential of lees, as well as the use of computational tools to optimize extraction and identify the molecules responsible for bioactive activity, is emphasized.

Valorization of Peach Fruit and Wine Lees through the Production of a Functional Peach and Grape Juice

The valorization of agri-food products not only represents important economic and environmental benefits but can also be a source of potentially profitable, functional, and safe ingredients. This study aimed to valorize peach fruit and wine lees (WL) by producing functional juice. WL were incorporated at different concentrations (1.5 and 2%; w:w) in unpasteurized peach and grape juice and subsequently stored under refrigeration (5 °C). The antimicrobial activity of WL in peach and grape juices was assessed against Listeria monocytogenes and Saccharomyces cerevisiae as well as physicochemical, nutritional microbiological, and sensory acceptability. The maximum addition of WL to the juice (2%) showed a significant inhibitory effect against L. monocytogenes (4-log reduction) and increased the content of total soluble solids (TSS) (10%), total polyphenol content (TPC) (75%), and total antioxidant activity (AOX) (86%). During storage, AOX, TPC, TSS, pH, and titratable acidity (TA) remained stable. A significant correlation was observed between TPC and AOX. Total mesophilic aerobic bacteria and yeast counts increased during storage. Fifty-seven percent of tasters (n = 26) rated the functional juice positively. Thus, these agri-food products could be useful for producing functional juices with a longer shelf life, contributing to their valorization.

Waste to value: Enhancing xanthan gum hydrogel with wine lees extract for optimal performance

The current study investigated the potential of utilizing wine lees extract (WLE) from red wine to enhance the sustainability and cost-effectiveness of xanthan gum (XG). A novel hydrogel system was successfully generated by cross-linking WLE and XG. Response surface methodology (RSM) was used to thoroughly analyze the characteristics of this novel hydrogel to understand its behavior and possible applications. Consistency index (K), flow behavior index (n), water holding capacity (%), and oil binding capacity (%) of the cross-linked hydrogels were optimized, and the best formulation was determined to be 0.81 % XG + 0.67 % WLE and crosslink temperature of 47 °C. The addition of WLE (0-1 % w/v) to different concentrations of XG (0-1 % w/v) was found to have a notable impact on the rheological properties, but changes in cross-link temperature (45-65 °C) did not have a significant effect. The activation energy was increased by incorporating WLE at XG concentration above 0.5 %, indicating a more robust and stable structure. FTIR and SEM analyses confirmed the chemical bonding structure of the optimum hydrogel. Incorporating WLE could significantly improve the functional properties of XG hydrogels, allowing the development of healthier product formulations.

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

BACKGROUND

The purpose of this study was to evaluate the potential of incorporating wine lees (WL), an inexpensive and widely available high-value winery waste product, into gelatin-based jellies to improve their technological and functional properties. We also aimed to evaluate the suitability of WL as a jelly colorant by comparing it with a commercial colorant.

RESULTS

Wine lees were characterized for their anthocyanin, phenolic, antioxidant, and mineral content. Subsequently, physicochemical, functional, textural, rheological, and thermal analyses were conducted on soft candies containing 21, 14, and 7 g kg-1 WL (labeled as WL30, WL20, and WL10, respectively). The total phenolic, anthocyanin, antioxidant, and cupric-reducing antioxidant capacity (CUPRAC) values of WL30 were determined as 57.80 ± 6.12 mg gallic acid equivalent per kilogram (GAE kg-1 ), 17.58 ± 0.36 mg malvidin-3-glucoside equivalent kg-1 , 0.04 ± 0.01 μg mL-1 , and 45.55 ± 1.00 mmol L-1 Trolox equivalent (TE), respectively. The control sample had the best rheological characteristics, including K', G', and n*, as well as the greatest hardness value, followed by WL30. However, during the storage period, WL30 exhibited superior color stability and retained higher levels of phenolic and anthocyanin components in comparison with the control sample.

CONCLUSION

Wine lees have the potential to be utilized as a natural colorant and alternative flavoring agent in jelly production. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Enhancing Anthocyanin Extraction from Wine Lees: A Comprehensive Ultrasound-Assisted Optimization Study

Wine lees, an important by-product of the wine industry, pose a major environmental problem due to the enormous quantities of solid-liquid waste that are discarded annually without defined applications. In this study, the optimization of a method based on a Box-Behnken design with surface response has been carried out to obtain extracts with high anthocyanin content and potent antioxidant activity. Six variables have been considered: %EtOH, temperature, amplitude, cycle, pH, and ratio. The developed method exhibited important repeatability properties and intermediate precision, with less than 5% CV being achieved. Furthermore, these novel methods were successfully applied to diverse wine lees samples sourced from Cabernet Sauvignon and Syrah varieties (Vitis vinifera), resulting in extracts enriched with significant anthocyanin content and noteworthy antioxidant activity. Additionally, this study evaluated the influence of grape variety, fermentation type (alcoholic or malolactic), and sample treatment on anthocyanin content and antioxidant activity, providing valuable insights for further research and application in various sectors. The potential applications of these high-quality extracts extend beyond the winemaking industry, holding promise for fields like medicine, pharmaceuticals, and nutraceuticals, thus promoting a circular economy and mitigating environmental contamination.

Recent Progress in Distiller's Grains: Chemical Compositions and Biological Activities

Distiller's grains (DGs) are solid mixtures that remain after the production of alcoholic beverages. A large amount of DGs is produced each year during the brewing process. Currently, they are mostly used as a feedstock or substrate in the feed industry. However, the lack of a comprehensive understanding of the chemical composition of DGs is a major constraint on their further development and application for high-value-added usages. Some studies were published on the bioactive constituents of DGs in several different types of journals. Data were therefore collated to provide a comprehensive overview of these natural products. DGs are rich in phenols, phytosterols, and fatty acids, in addition to general lipid and protein constituents. These compounds and their related extracts possess diverse biological activities, including antioxidant, anti-inflammatory, and anti-hyperglycaemic effects. We hope that this review will provide research incentives for the further development and utilisation of DGs to develop high-value-added products.

Comparative Methods to Evaluate the Antioxidant Capacity of Propolis: An Attempt to Explain the Differences

Propolis is a natural product produced by bees that contains a complex mixture of compounds, including phenolic compounds and flavonoids. These compounds contribute to its biological activities, such as antioxidant capacity. This study analysed the pollen profile, total phenolic content (TPC), antioxidant properties, and phenolic compound profile of four propolis samples from Portugal. The total phenolic compounds in the samples were determined by six different techniques: four different Folin-Ciocalteu (F-C) methods, spectrophotometry (SPECT), and voltammetry (SWV). Of the six methods, SPECT allowed the highest quantification, while SWV achieved the lowest. The mean TPC values for these methods were 422 ± 98 and 47 ± 11 mg GAE/g sample, respectively. Antioxidant capacity was determined by four different methods: DPPH, FRAP, original ferrocyanide (OFec), and modified ferrocyanide (MFec). The MFec method gave the highest antioxidant capacity for all samples, followed by the DPPH method. The study also investigated the correlation between TPC and antioxidant capacity with the presence of hydroxybenzoic acid (HBA), hydroxycinnamic acid (HCA), and flavonoids (FLAV) in propolis samples. The results showed that the concentrations of specific compounds in propolis samples can significantly impact their antioxidant capacity and TPC quantification. Analysis of the profile of phenolic compounds by the UHPLC-DAD-ESI-MS technique identified chrysin, caffeic acid isoprenyl ester, pinocembrin, galangin, pinobanksin-3-O-acetate, and caffeic acid phenyl ester as the major compounds in the four propolis samples. In conclusion, this study shows the importance of the choice of method for determining TPC and antioxidant activity in samples and the contribution of HBA and HCA content to their quantification.

Antiherpetic Activity of Taurisolo®, a Grape Pomace Polyphenolic Extract

Herpes simplex virus (HSV) is widespread in the population, causing oral or genital ulcers and, rarely, severe complications such as encephalitis, keratitis, and neonatal herpes. Current available anti-HSV drugs are acyclovir and its derivatives, although long-term therapy with these agents can lead to drug resistance. Thus, the discovery of novel antiherpetic compounds merits additional studies. In recent decades, much scientific effort has been invested in the discovery of new synthetic or natural compounds with promising antiviral properties. In our study, we tested the antiviral potential of a novel polyphenol-based nutraceutical formulation (named Taurisolo^®) consisting of a water polyphenol extract of grape pomace. The evaluation of the antiviral activity was carried out by using HSV-1 and HSV-2 in plaque assay experiments to understand the mechanism of action of the extract. Results were confirmed by real-time PCR, transmission electron microscope (TEM), and fluorescence microscope. Taurisolo^® was able to block the viral infection by acting on cells when added together with the virus and also when the virus was pretreated with the extract, demonstrating an inhibitory activity directed to the early phases of HSV-1 and HSV-2 infection. Altogether, these data evidence for the first time the potential use of Taurisolo^® as a topical formulation for both preventing and healing herpes lesions.

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

The conversion of plant byproducts, which are phenolic-rich substrates, to valuable co-products by implementing non-conventional extraction techniques is the need of the hour. In the current study, ultrasound- (UAE) and microwave-assisted extraction (MAE) were applied for the recovery of polyphenols from peach byproducts. Two-level screening and Box-Behnken design were adopted to optimize extraction efficiency in terms of total phenolic content (TPC). Methanol:water 4:1% v/v was the extraction solvent. The optimal conditions of UAE were 15 min, 8 s ON-5 s OFF, and 35 mL g^-1, while MAE was maximized at 20 min, 58 °C, and 16 mL g^-1. Regarding the extracts' TPC and antioxidant activity, MAE emerged as the method of choice, whilst their antiradical activity was similar in both techniques. Furthermore, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine chlorogenic acid and naringenin in byproducts' extracts. 4-Chloro-4'-hydroxybenzophenone is proposed as a new internal standard in LC-MS/MS analysis in foods and byproducts. Chlorogenic acid was extracted in higher yields when UAE was used, while MAE favored the extraction of the flavonoid compound, naringenin. To conclude, non-conventional extraction could be considered as an efficient and fast alternative for the recovery of bioactive compounds from plant matrices.