Phenolic characterization of aging wine lees: Correlation with antioxidant activities

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.

Exploring the Antioxidant Potential of Phenolic Compounds from Winery By-Products by Hydroethanolic Extraction

The residues generated in the wine industry (pomace, stems, seeds, wine lees, and grapevine shoots) are a potential source of bioactive compounds that can be used in other industries despite being sometimes underestimated. Different extraction methods using various solvents and extraction conditions are currently being investigated. Due to its natural occurrence in wines, safe behavior, and low toxicity when compared to other organic solvents, ethanol is used as an extracting agent. The aim of this study was to identify the winery by-product from the Região Demarcada do Douro and its corresponding extraction solvents that yields the most favorable results in (poly)phenols content and antioxidant capacity. To achieve this, five different ratios of ethanol: water, namely 0:100, 25:75, 50:50, 75:25, and 100:0 (v/v), for extracting the phenolic compounds were employed. Afterwards, the determination of total phenolic content (TPC), ortho-diphenols content (ODC), and flavonoid content (FC) as well as the antioxidant capacity of the obtained extracts using three different methods was performed. Since the best results of the spectrophotometric assays were obtained mostly with hydroethanolic extracts of stems (50:50, v/v), identification by HPLC-DAD has carried out. It was possible to conclude that the Tinta Roriz variety displayed the highest number of identified (poly)phenols.

Preparative Fractionation of Phenolic Compounds and Isolation of an Enriched Flavonol Fraction from Winemaking Industry By-Products by High-Performance Counter-Current Chromatography

High-performance counter-current chromatography (HPCCC) was used as a tool for the isolation and fractionation of phenolic compounds (PCs) in extracts from wine lees (WL) and grape pomace (GP). The biphasic solvent systems applied for HPCCC separation were n-butanol:methyl tert-butyl ether:acetonitrile:water (3:1:1:5) with 0.1% trifluoroacetic acid (TFA) and n-hexane:ethyl acetate:methanol:water (1:5:1:5). After refining the ethanol:water extracts of GP and WL by-products by ethyl acetate extraction, the latter system yielded an enriched fraction of the minor family of flavonols. Recoveries of 112.9 and 105.9 mg of purified flavonols (myricetin, quercetin, isorhamnetin, and kaempferol) in GP and WL, respectively, from 500 mg of ethyl acetate extract (equivalent to 10 g of by-product) were obtained. The HPCCC fractionation and concentration capabilities were also exploited for the characterization and tentative identification of constitutive PCs by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). In addition to the isolation of the enriched flavonol fraction, a total of 57 PCs in both matrixes were identified, 12 of which were reported for the first time in WL and/or GP. The application of HPCCC to GP and WL extracts may be a powerful approach to isolate large amounts of minor PCs. The composition of the isolated fraction demonstrated quantitative differences in the individual compound composition of GP and WL, supporting the potential exploitation of these matrixes as sources of specific flavonols for technological applications.

Phytochemicals from Phillyrea latifolia L. leaves and fruit extracted with various solvents: Their identification and quantification by LC-MS and antihyperglycemic effects

Phillyrea latifolia L. is a type of shrubland, which is widely known as mock privet, and belongs to the Oleaceae family. The objective of this study was to compare and assess the phytochemical composition, antioxidant and antidiabetic activities of ethyl acetate, methanol and aqueous extracts of the fruit and leaves of P. latifolia L. Phenolics were analysed by detecting individual bioactive compounds using an LCMS-2020 quadrupole mass spectrometer and by calculating total phenolic content (TPC). For the first time, the antioxidant and antidiabetic activities of both leaves and fruit were determined using DPPH radical scavenging. The aqueous extract was indicated to have higher antioxidant activities than ethyl acetate and methanol extracts. The individual constituents within the different extracts for both fruit and leaves were detected as the luteolin-7-O-glucoside in the ethyl acetate (854 μg · g–1 and 1,098 μg · g–1), methanol (1,241 μg · g–1 and 2,136.43 μg · g–1) and aqueous (509 μg · g–1 and 898.23 μg · g–1) extracts, respectively. Extractions of ethyl acetate and methanol demonstrated stronger inhibitory activity against human salivary α-amylase than the aqueous extract of both parts of the mock privet. Similarly, extraction of ethyl acetate from the leaves and fruit of the mock privet indicated significantly better inhibitory activity than the methanol and aqueous extracts, respectively, for the inhibition of α-glucosidase activity. This study indicates that both fruit and leaves of mock privet may use as a potential source of natural biomolecules to promote healthy activities.

Functional Foods Acceptability: A Consumers' Survey on Bread Enriched with Oenological By-Products

In recent years, consumers have shown considerable attention to functional foods that can provide various benefits. At the same time, the awareness of the problem of waste generation from the agri-food supply chains has increased; thus, scholars and practitioners are devoting great attention to sustainable food waste management. Within the wine processing, the production phase generates by-products such as marc, grape seeds, stems, and wine lees. In most cases, these by-products are treated as waste rather than as a resource, creating environmental, economic, and social impacts related to their disposal. By contrast, the reuse of oenological by-products in food production can have several health benefits, since they are rich in functional molecules such as fibres, polyphenols, and vitamin E, and can also trigger a circular economy model. The aim of this research is to investigate the acceptance of consumers towards bread enriched with oenological by-products through the application of k-means clustering, providing insights on the characterisation of groups of consumers based on their specific features and declared attitudes. The results showed three different consumers' clusters, highlighting that the acceptance of this enriched bread is not influenced by the consumers' socio-economic features, but it is related to consumers' sensitivity. Therefore, target strategies should be put in place to inform consumers about the benefits associated with the consumption of bread enriched with oenological by-products.

Chemical Characterization and Bioactive Properties of Wine Lees and Diatomaceous Earth towards the Valorization of Underexploited Residues as Potential Cosmeceuticals

Annually, wine production is responsible for generating large quantities of residues, which are frequently disposed of and not valorized. So far, different studies have been conducted on grape pomace, yet less attention has been paid to other residues, such as wine lees and diatomaceous earth used in wine filtration. In this context, this study aimed to evaluate and compare the phenolic profile of these underexploited winemaking residues and assess their biological potential based on their antioxidant, antimicrobial, cytotoxic, and anti-aging activities (inhibition of tyrosinase and collagenase). Twenty-nine phenolic compounds, including twelve anthocyanins, were tentatively identified in the residues, with red grape pomace showing the highest diversity of compounds. The diatomaceous earth presented the highest content of non-anthocyanin phenolic compounds, being particularly rich in flavan-3-ols and myricetin-O-hexoside, and also presenting two anthocyanins. This sample also showed a high antioxidant activity, evidencing the best result in the reducing power assay. The red wine lees extract, despite showing a low content of phenolic compounds and less antioxidant activity, presented the highest inhibition capacity of bacteria growth. The extracts did not exhibit cytotoxicity against keratinocyte (up to 400 μg/mL) and fibroblast (up to 100 μg/mL) skin cell lines. However, the capacity of inhibiting tyrosinase and collagenase was low for the lees and diatomaceous earth, contrary to the grape pomace, seeds, and skins extracts that showed promising results, evidencing its potential as a cosmeceutical. Overall, this study highlights for the first time the potential of diatomaceous earth, an underexploited winemaking waste, in the obtention of added-value extracts and/or ingredients for cosmetic industry.

Wine Lees as Source of Antioxidant Molecules: Green Extraction Procedure and Biological Activity

An ultrasound-assisted extraction method, employing ethanol and water as solvents at low temperature (30 °C) and reduced time (15 min), was proposed to extract bioactive molecules from different cultivars (Magliocco Canino, Magliocco Rosato, Gaglioppo, and Nocera Rosso) of wine lees. All the extract yields were evaluated and their contents of phenolic acids, flavonoids, and total polyphenols were determined by means of colorimetric assays and high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and Fourier transform infrared (FTIR) techniques. Radical scavenging assays were performed and the Magliocco Canino extracted with a hydroalcoholic mixture returned the best results both against ABTS (0.451 mg mL−1) and DPPH (0.395 mg mL−1) radicals. The chemometric algorithms principal component analysis (PCA) and partial least square regression (PLS) were used to process the data obtained from all qualitative–quantitative sample determinations with the aim of highlighting data patterns and finding possible correlations between composition and antioxidant features of the different wine lees cultivars and the extraction procedures. Wine lees from Magliocco Canino and Magliocco Rosato were found to be the best vegetable matrices in terms of metabolite content and antioxidant properties. The components extracted with alcoholic or hydroalcoholic solvents, specifically (−)-epigallocatechin gallate, chlorogenic acid, and trans-caftaric acid, were found to be correlated with the antioxidant capacity of the extracts. Multivariate data processing was able to identify the compounds related to the antioxidant features. Two PLS models were optimized by using their concentration levels to predict the IC50 values of the extracts in terms of DPPH and ABTS with high values of correlation coefficient R2, 0.932 and 0.824, respectively, and a prediction error lower than 0.07. Finally, cellular (SH-SY5Y cells) antioxidant assays were performed on the best extract (the hydroalcoholic extract of Magliocco Canino cv) to confirm its biological performance against radical species. All these recorded data strongly outline the aptness of valorizing wine lees as a valuable source of antioxidants.

The (Poly)phenolic Profile of Separate Winery By-Products Reveals Potential Antioxidant Synergies

The by-products of grapes (Vitis vinifera L.) in the winemaking process present a diverse phytochemical profile of (poly)phenols, essentially represented by phenolic acids, flavonoids, and stilbenes, which have health benefits. In winemaking, solid (grape stems and pomace) and semisolid (wine lees) by-products are generated, negatively impacting the sustainability of the agro-food activity and the local environment. Although information on the phytochemical profile of grape stems and pomace has been reported, especially information concerning (poly)phenols, research on wine lees is necessary to take advantage of the compositional traits of this residue. So, in the present work, an updated, in-depth comparison of the (poly)phenolic profiles of these three resulting matrices in the agro-food industry has been carried out to provide new knowledge and interesting data on the action of yeast and lactic acid bacteria (LAB) metabolism in the diversification of phenolic composition; additionally, we extract complementarities for the possible joint application of the three residues. The phytochemical analysis of the extracts was carried out using HPLC-PDA-ESI-MSn. The (poly)phenolic profiles of the residues showed significant discrepancies. The results obtained showed that the greatest diversity of (poly)phenols was found in the stems of the grapes, followed closely by the lees. Through technological insights, it has been suggested that yeasts and LAB, responsible for the fermentation of must, might play a key role in the transformation of phenolic compounds. This would provide new molecules with specific bioavailability and bioactivity features, which might interact with different molecular targets and, consequently, improve the biological potential of these underexploited residues.

Recovery of phenolic compounds from wine lees using green processing: Identifying target molecules and assessing membrane ultrafiltration performance

Winery wastes are rich in polyphenols with high added value to be used in cosmetics, pharmaceuticals, and food products. This work aims at recovering and purifying the polyphenolic fraction occurring in the malolactic fermentation lees generated during the production of Albariño wines. Phenolic acids, flavonoids, and related compounds were recovered from this oenological waste by green liquid extraction using water as the solvent. The resulting extract solution was microfiltered to remove microparticles and further treated by ultrafiltration (UF) using membranes of 30 kDa and 5 kDa molecular weight cut-offs (MWCOs). The feed sample and the filtrate and retentate solutions from each membrane system were analyzed by reversed-phase liquid chromatography (HPLC) with UV and mass spectrometric (MS) detection. The most abundant polyphenols in the extracts were identified and quantified, namely: caftaric acid with a concentration of 200 µg g^-1 and trans-coutaric acid, cis-coutaric acid, gallic acid, and astilbin with concentrations between 15 and 40 µg g^-1. Other minor phenolic acids and flavanols were also found. The UF process using the 30 kDa membrane did not modify the extract composition, but filtration through the 5 kDa poly-acrylonitrile membrane elicited a decrease in polyphenolic content. Hence, the 30 kDa membrane was recommended to further pre-process the extracts. The combined extraction and purification process presented here is environmentally friendly and demonstrates that malolactic fermentation lees of Albariño wines are a valuable source of phenolic compounds, especially phenolic acids.

Multi-feedstock biorefinery concept: Valorization of winery wastes by engineered yeast

The wine industry produces significant amounts of by-products and residues that are not properly managed, posing an environmental problem. Grape must surplus, vine shoots, and wine lees have the potential to be used as renewable resources for the production of energy and chemicals. Metabolic engineering efforts have established Saccharomyces cerevisiae as an efficient microbial cell factory for biorefineries. Current biorefineries designed for producing multiple products often rely on just one feedstock, but the bioeconomy would clearly benefit if these biorefineries could efficiently convert multiple feedstocks. Moreover, to reduce the environmental impact of fossil fuel consumption and maximize production economics, a biorefinery should be capable to supplement the manufacture of biofuel with the production of high-value products. This study proposes an integrated approach for the valorization of diverse wastes resulting from winemaking processes through the biosynthesis of xylitol and ethanol. Using genetically modified S. cerevisiae strains, the xylose-rich hemicellulosic fraction of hydrothermally pretreated vine shoots was converted into xylitol, and the cellulosic fraction was used to produce bioethanol. In addition, grape must, enriched in sugars, was efficiently used as a low-cost source for yeast propagation. The production of xylitol was optimized, in a Simultaneous Saccharification and Fermentation process configuration, by adjusting the inoculum size and enzyme loading. Furthermore, a yeast strain displaying cellulases in the cell surface was applied for the production of bioethanol from the glucan-rich cellulosic. With the addition of grape must and/or wine lees, high ethanol concentrations were reached, which are crucial for the economic feasibility of distillation. This integrated multi-feedstock valorization provides a synergistic alternative for converting a range of winery wastes and by-products into biofuel and an added-value chemical while decreasing waste released to the environment.

Identification and Antioxidant Capacity of Free and Bound Phenolics in Six Varieties of Mulberry Seeds Using UPLC-ESI-QTOF-MS/MS

Mulberry seeds are a byproduct of juice processing and may be an important resource for its abundant compounds. In this study, we analyzed the qualitative composition of free and bound phenolics from six varieties of mulberry seeds using UPLC-ESI-QTOF-MS/MS. Free phenolics (FPs) and bound phenolics (BPs) were measured using the Folin–Ciocalteu method; antioxidant capacity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, using the ferric reducing antioxidant power assay. A total of 28 free and 11 bound phenolics were extracted and identified, wherein five free phenolics were found in mulberry matrices for the first time. The six varieties of mulberry seeds exhibited higher content of FPs than BPs, and there was a correlation between the phenolic content and antioxidant capacity. Consequently, three varieties were selected for their high phenolic content and antioxidant capacity. This study might offer a theoretical basis for the utilization of mulberry seed.

A green approach to phenolic compounds recovery from olive mill and winery wastes

The aim of this study was to evaluate the recovery of phenolic compounds from olive mill and winery wastes by conventional solid-liquid extraction (SLE) using water as the extraction solvent. The studied variables were extraction time (5-15 min), temperature (25-90 °C), solid-to-liquid ratio (1:10-1:100 (kg/L)), pH (3-10) and application of multiple extractions (1-3). The extraction efficiency was evaluated in terms of total phenolic content (TPC), determined by high performance liquid chromatography (HPLC-UV), but also from the recovery of some representative phenolic compounds. The optimized conditions were one extraction step, 10 min, 25 °C, 1:30 (kg/L), pH 5 for olive pomace, and one extraction step, 10 min, 70 °C, 1:100 (kg/L), pH 5 for winery residues. The extraction method is simple and suitable for scaling-up in industry, and the aqueous extracts are fully compatible with further purification schemes based on the use of membranes or resins. The optimized technique was applied to a set of different representative residues from olive mill and winery industries, to assess their suitability as sources for phenolic compounds recovery. The phenolic content in the extracts was evaluated by chromatographic analysis and by the Folin-Ciocalteu assay (FC). Furthermore, the antioxidant capacity was determined by 2,2-azinobis-3-etilbenzotiazolina-6-sulfonat (ABTS), 2,-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Because of their high contents in phenolic compounds and great antioxidant capacity, olive pomace and lees filters were identified as especially suited sources for phenolic compounds recovery.

Changes in the antioxidant activity of red dry wines depending on the production method

It is found that a production method affects the antioxidant activity of researched red dry wines made grapes produced in Kuban area. According to results of multivariate analysis of variance, grape variety (59% of influence), production method (27%) and usage of antioxidants during must extraction (7%) influenced on antioxidant activity values.

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

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.

Sequential Membrane Filtration to Recover Polyphenols and Organic Acids from Red Wine Lees: The Antioxidant Properties of the Spray-Dried Concentrate

The vinification process produces a considerable amount of waste. Wine lees are the second most generated byproduct, representing around 14% of total vinification wastes. They are a valuable source of natural antioxidants, mainly polyphenols, as well as organic acids, such as tartaric acid. This paper deals with the application of an integrated, environment friendly membrane separation process to recover polyphenols and organic acids. A two-step membrane process is described, consisting of an ultra- and a nano-filtration process. The physicochemical and antioxidant properties of all the process streams were determined. High Pressure Liquid Chromatography (HPLC) was employed for identifying certain individual organic acids and polyphenols, while the antioxidant potential was determined by the 2,2′-diphenyl-1-picrylhydrazyl radical) (DPPH) radical scavenging ability and ferric reducing ability. A liquid concentrate stream containing 1351 ppm of polyphenols was produced and then spray dried. The resulting powder retained most of the polyphenols and antioxidant properties and was successfully applied to a real food system to retard lipid oxidation, followed by Thiobarbituric Acid Reactive Substances (TBARS) and the determination of oxymyoglobin content. The results show that membrane separation technology is an attractive alternative process for recovering value-added ingredients from wine lees.

Integration of Nanofiltration and Reverse Osmosis Technologies in Polyphenols Recovery Schemes from Winery and Olive Mill Wastes by Aqueous-Based Processing

More sustainable waste management in the winery and olive oil industries has become a major challenge. Therefore, waste valorization to obtain value-added products (e.g., polyphenols) is an efficient alternative that contributes to circular approaches and sustainable environmental protection. In this work, an integration scheme was purposed based on sustainable extraction and membrane separation processes, such as nanofiltration (NF) and reverse osmosis (RO), for the recovery of polyphenols from winery and olive mill wastes. Membrane processes were evaluated in a closed-loop system and with a flat-sheet membrane configuration (NF270, NF90, and Duracid as NF membranes, and BW30LE as RO membrane). The separation and concentration efficiency were evaluated in terms of the total polyphenol content (TPC), and by polyphenol families (hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids), using high-performance liquid chromatography. The water trans-membrane flux was dependent on the trans-membrane pressure for the NF and RO processes. NF90 membrane rejected around 91% of TPC for the lees filters extracts while NF270 membrane rejected about 99% of TPC for the olive pomace extracts. Otherwise, RO membranes rejected more than 99.9% of TPC for both types of agri-food wastes. Hence, NF and RO techniques could be used to obtain polyphenol-rich streams, and clean water for reuse purposes.

Winery by-products as a valuable source for natural antihypertensive agents

Hypertension (HTN) is one of the leading causes of death in the world. Agri-food by-products are emerging as a novel source of natural antihypertensive agents allowing for their valorization and making food and agricultural industries more environmentally friendly. In this regard, wine making process generates large amounts of by-products rich in phenolic compounds that have shown potential to exert several beneficial effects including antihypertensive properties. The aim of this study was to review the blood pressure-lowering effects of winery by-products. In addition, molecular mechanisms involved in their bioactivity were also evaluated. Among the winery by-products, grape seed extracts have widely shown antihypertensive properties in both animal and human studies. Moreover, recent evidence suggests that grape stem, skin and pomace and wine lees may also have great potential to manage HTN, although more studies are needed in order to confirm their potential in humans. Improvement of endothelial dysfunction and reduction of oxidative stress associated with HTN are the main mechanisms involved in the blood pressure-lowering effects of these by-products.

Revalorization of Cava Lees to Improve the Safety of Fermented Sausages

The revalorization of food processing by-products not only reduces the environmental impact of their disposal, but also generates added economic value. Cava lees consist of inactive cells of Saccharomyces cerevisiae, and though regarded as a valueless winery by-product, they are rich in fiber and phenolic compounds. In this study, a challenge test was performed to assess the effect of cava lees and a phenolic extract (LPE) derived therefrom on the behaviour of technological microbiota (lactic acid bacteria used as a starter culture) and the foodborne pathogens Salmonella spp. and Listeria monocytogenes during the fermentation and ripening of pork sausages. Ten batches of fermented sausages were prepared with and without cava lees or the LPE, and with or without different strains of Latilactobacillus sakei (CTC494 or BAP110). The addition of cava lees reduced the pH values of the meat batter throughout the fermentation and ripening process. No growth-promoting effect on spontaneous lactic acid bacteria (LAB) or the starter culture was observed. In contrast, the presence of cava lees prevented the growth of the tested pathogens (Salmonella and L. monocytogenes), as did the starter culture, resulting in significantly lower counts compared to the control batch. In addition, the combination of cava lees with L. sakei CTC494 had a bactericidal effect on Salmonella. LPE supplementation did not affect the pH values or LAB counts but reduced the mean counts of Salmonella, which were 0.71 log10 lower than the control values at the end of the ripening. The LPE did not exert any additional effect to that of the starters applied alone. The revalorization of cava lees as a natural ingredient to improve the microbiological safety of fermented sausages is a feasible strategy that would promote a circular economy and benefit the environment.

A Simple Method for Evaluating the Bioactive Phenolic Compounds' Presence in Brazilian Craft Beers

There are a significant number of analytical methodologies employing different techniques to determine phenolic compounds in beverages. However, these methods employ long sample preparation processes and great time consumption. The aim of this paper was the development of a simple method for evaluating the phenolic compounds’ presence in Brazilian craft beers without a previous extraction step. Catechin, caffeic acid, epicatechin, p-coumaric acid, hydrated rutin, trans-ferulic acid, quercetin, kaempferol, and formononetin were analyzed in fifteen different craft beers. The method showed good linearity (R² ≥ 0.9966). The limit of detection ranged from 0.08 to 0.83 mg L⁻¹, and limits of quantification were between 0.27 and 2.78 mg L⁻¹. The method showed a satisfactory precision (RSD ≤ 16.2%). A good accuracy was obtained by the proposed method for all phenolic compounds in craft beer (68.6% ˂ accuracy ˂ 112%). Catechin showed higher concentrations (up to 124.8 mg L⁻¹) in the samples, followed by epicatechin (up to 51.1 mg L⁻¹) and caffeic acid (up to 8.13 mg L⁻¹). Rutin and formononetin were observed in all analyzed samples (0.52 mg L⁻¹ to 2.40 mg L⁻¹), and kaempferol was less present in the samples. The presence of plant origin products was determinant for the occurrence of the highest concentrations of phenolic compounds in Brazilian craft beers.

Antioxidant Determination with the Use of Carbon-Based Electrodes

Antioxidants are compounds that prevent or delay the oxidation process, acting at a much smaller concentration, in comparison to that of the preserved substrate. Primary antioxidants act as scavenging or chain breaking antioxidants, delaying initiation or interrupting propagation step. Secondary antioxidants quench singlet oxygen, decompose peroxides in non-radical species, chelate prooxidative metal ions, inhibit oxidative enzymes. Based on antioxidants’ reactivity, four lines of defense have been described: Preventative antioxidants, radical scavengers, repair antioxidants, and antioxidants relying on adaptation mechanisms. Carbon-based electrodes are largely employed in electroanalysis given their special features, that encompass large surface area, high electroconductivity, chemical stability, nanostructuring possibilities, facility of manufacturing at low cost, and easiness of surface modification. Largely employed methods encompass voltammetry, amperometry, biamperometry and potentiometry. Determination of key endogenous and exogenous individual antioxidants, as well as of antioxidant activity and its main contributors relied on unmodified or modified carbon electrodes, whose analytical parameters are detailed. Recent advances based on modifications with carbon-nanotubes or the use of hybrid nanocomposite materials are described. Large effective surface area, increased mass transport, electrocatalytical effects, improved sensitivity, and low detection limits in the nanomolar range were reported, with applications validated in complex media such as foodstuffs and biological samples.

Enzyme-Assisted Extraction to Obtain Phenolic-Enriched Wine Lees with Enhanced Bioactivity in Hypertensive Rats

The antihypertensive effect of the soluble fraction of wine lees (WL) from Cabernet variety grapes was recently reported by our group. This blood pressure (BP)-lowering effect was attributed to the presence of flavanols and anthocyanins. In this context, phenolic-enriched wine lees (PWL) could potentially exhibit a stronger bioactivity. Therefore, the aim of this study was to obtain a soluble fraction of WL with increased phenolic content and evaluate its functionality. The PWL were obtained using an enzyme-assisted extraction based on the hydrolysis of WL proteins with Flavourzyme^®. They contained 57.20% more total phenolic compounds than WL, with anthocyanins and flavanols being the largest families present. In addition, PWL also showed greater angiotensin-converting enzyme inhibitory and antioxidant activities. Finally, the antihypertensive activity of the PWL was evaluated in spontaneously hypertensive rats. A single dose of 5 mL/kg body weight of PWL showed a greater BP-lowering effect than the one shown by WL. Moreover, this antihypertensive effect was more prolonged than the one produced by the antihypertensive drug Captopril. These results demonstrate that enzymatic protein hydrolysis is a useful method to maximize the extraction of phenolic compounds from WL and to obtain extracts with enhanced functionalities.

ACE Inhibitory and Antihypertensive Activities of Wine Lees and Relationship among Bioactivity and Phenolic Profile

Wine lees (WL) are by-products generated in the winemaking process. The aim of this study was to investigate the angiotensin-converting enzyme inhibitory (ACEi) activity, and the blood pressure (BP) lowering effect of WL from individual grape varieties. The relationship among their activities and phenolic profiles was also studied. Three WL, from Cabernet, Mazuela, and Garnacha grape varieties, were firstly selected based on their ACEi properties. Their phenolic profiles were fully characterized by UHPLC-ESI-Q-TOF-MS. Then, their potential antihypertensive effects were evaluated in spontaneously hypertensive rats (SHR). BP was recorded before and after their oral administrations (2, 4, 6, 8, 24, and 48 h) at a dose of 5 mL/kg bw. Cabernet WL (CWL) exhibited a potent antihypertensive activity, similar to that obtained with the drug Captopril. This BP-lowering effect was related to the high amount of anthocyanins and flavanols present in these lees. In addition, a potential hypotensive effect of CWL was discarded in normotensive Wistar-Kyoto rats. Finally, the ACEi and antihypertensive activities of CWL coming from a different harvest were confirmed. Our results suggest the potential of CWL for controlling arterial BP, opening the door to commercial use within the wine industry.

Biological properties of almond proteins produced by aqueous and enzyme-assisted aqueous extraction processes from almond cake

The almond cake is a protein-rich residue generated by the mechanical expression of the almond oil. The effects of the aqueous (AEP) and enzyme-assisted aqueous extraction processes (EAEP) on the biological properties of the almond cake protein were evaluated. Total phenolic content (TPC), antioxidant capacity, inhibitory effects against crucial enzymes related to metabolic syndrome, antimicrobial potential, and in vitro protein digestibility profile were assessed. EAEP provided the best results for antioxidant capacity by both ORAC (397.2 µmol TE per g) and ABTS (650.5 µmol TE per g) methods and also showed a high (~ 98%) potential for α-glucosidase inhibition. The AEP resulted in protein extracts with the highest lipase inhibition (~ 70%) in a dose-dependent way. Enzymatic kinetic analyses revealed that EAEP generated uncompetitive inhibitors against α-glucosidase, while EAEP, AEP, and HEX-AEP (used as control) generated the same kind of inhibitors against lipase. No protein extract was effective against any of the bacteria strains tested at antimicrobial assays. An in silico theoretical hydrolysis of amandin subunits corroborated with the results found for antioxidant capacity, enzyme inhibitory experiments, and antimicrobial activity. Digestibility results indicated that the digestive proteases used were efficient in hydrolyzing almond proteins, regardless of the extraction applied and that HEX-AEP presented the highest digestibility (85%). In summary, EAEP and AEP skim proteins have the potential to be used as a nutraceutical ingredient. The biological properties observed in these extracts could help mitigate the development of metabolic syndrome where EAEP and AEP skim proteins could be potentially used as a prophylactic therapy for diabetes and obesity, respectively.

Current and future strategies for wine yeast lees valorization

Wine lees is a sludge material mainly composed of dead yeast precipitated at the bottom of wine tanks. Along with grape pomace and grape stalks, it is one of the main by-products of the winemaking industry. Given that wine lees are considered a soil pollutant, their disposal represents a cost for wineries. Numerous wine lees recovery and valorization strategies have been proposed, with a particularly steep increase in published research in recent years. This attention is strictly linked to the concepts of circular economy and environmental sustainability that are attracting the interest of the scientific community. In this review, an overview on the available wine lees recovery and valorization strategies is reported. Additionally, the methods for the extraction and valorization of yeast's cell wall polysaccharides (β-glucans and mannoproteins) are discussed. Finally, current and future innovative applications in different sectors of yeast β-glucans and mannoproteins are described and critically discussed.

One injection to profile the chemical composition and dual-antioxidation activities of Rosa chinensis Jacq

An on-line high-performance liquid chromatography-diode-array-detector-electrospray ionization-ion-trap-time-of-flight-mass spectrometry-total antioxidant capacity detection (HPLC-DAD-ESI-IT-TOF-MS-TACD) system was applied for the identification and evaluation of antioxidants in Rosa chinensis Jacq., an edible flower in food industry and a widely used traditional Chinese medicine. With the help of this platform, the HPLC fingerprint, mass fragmentations, and sample activity profiles against 1,1-diphenylpicryl-2-hydrazyl radical (DPPH•) and ferric reducing antioxidant power (FRAP) were recorded after one injection. Using this technique, 80 compounds were separated and identified by their LC/MS behaviors with the assistance of standard compounds. In addition, 11 different Rosa chinensis Jacq. samples were profiled and then quantified for their DPPH• and FRAP activities. Interestingly, a total of 52 compounds showed antioxidative effects against DPPH• and 61 were active against FRAP. The results demonstrated that the on-line system is a powerful technique for antioxidant discovery in Rosa chinensis Jacq. and other food resources.

Polyphenol-Rich Extracts Obtained from Winemaking Waste Streams as Natural Ingredients with Cosmeceutical Potential

Phenolics present in grapes have been explored as cosmeceutical principles, due to their antioxidant activity and ability to inhibit enzymes relevant for skin ageing. The winemaking process generates large amounts of waste, and the recovery of bioactive compounds from residues and their further incorporation in cosmetics represents a promising market opportunity for wine producers and may contribute to a sustainable development of the sector. The extracts obtained from grape marc and wine lees, using solid-liquid (SL) extraction with and without microwave (MW) pretreatment of the raw material, were characterized in terms of antioxidant activity through chemical (ORAC/HOSC/HORAC) and cell-based (keratinocytes-HaCaT; fibroblasts-HFF) assays. Furthermore, their inhibitory capacity towards specific enzymes involved in skin ageing (elastase; MMP-1; tyrosinase) was evaluated. The total phenolic and anthocyanin contents were determined by colorimetric assays, and HPLC-DAD-MS/MS was performed to identify the main compounds. The MW pretreatment prior to conventional SL extraction led to overall better outcomes. The red wine lees extracts presented the highest phenolic content (3 to 6-fold higher than grape marc extracts) and exhibited the highest antioxidant capacity, being also the most effective inhibitors of elastase, MMP-1 and tyrosinase. The results support that winemaking waste streams are valuable sources of natural ingredients with the potential for cosmeceutical applications.

Triterpene Acid and Phenolics from Ancient Apples of Friuli Venezia Giulia as Nutraceutical Ingredients: LC-MS Study and In Vitro Activities

Triterpene acid and phenolic constituents from nine ancient varieties of apple (Malus domestica) fruits cultivated in Fanna, Friuli Venezia Giulia region, northeast Italy, were analyzed and compared with four commercial apples ('Golden Delicious', 'Red Delicious', 'Granny Smith' and 'Royal Gala'). Total phenolic and flavonoid contents were measured by spectrophotometric assays. The quali-quantitative fingerprint of secondary metabolites including triterpene acid was obtained by LC-DAD-(ESI)-MS and LC-(APCI)-MS, respectively. Based on the two LC-MS datasets, multivariate analysis was used to compare the composition of ancient fruit varieties with those of four commercial apples. Significant differences related mainly to the pattern of triterpene acids were found. Pomolic, euscaphyc, maslinic and ursolic acids are the most abundant triterpene in ancient varieties pulps and peels, while ursolic and oleanolic acids were prevalent in the commercial fruits. Also, the content of the phenolic compounds phloretin-2-O-xyloglucoside and quercetin-3-O-arabinoside was greater in ancient apple varieties. The antioxidant (radical scavenging, reducing power, metal chelating and phosphomolybdenum assays) and enzyme inhibitory effects (against cholinesterase, tyrosinase, amylase and glucosidase) of the samples were investigated in vitro. Antioxidant assays showed that the peels were more active than pulps. However, all the samples exhibited similar enzyme inhibitory effects. Ancient Friuli Venezia Giulia apple cultivars can be a source of chlorogenic acid and various triterpene acids, which are known for their potential anti-inflammatory activity and beneficial effects on lipid and glucose metabolism. Our results make these ancient varieties suitable for the development of new nutraceutical ingredients.

Wine Lees as a Source of Antioxidant Compounds

The winemaking industry produces large amount of byproducts, including grape pomace, stalks, and lees. Wine lees are a natural source of phenolic compounds, which have important antioxidant and biological properties. Due to the high quantities produced worldwide, this byproduct can be an ideal raw material for obtaining phenolic compounds that could be of interest in the food and pharmaceutical industries. In this mini review, the main characteristics of wine lees as well as their phenolic composition and antioxidant activity have been summarized from the information in the literature.

Phenolic compounds and bioactivity evaluation of aqueous and methanol extracts of Allium mongolicum Regel

Allium mongolicum Regel (AM), widely distributed in western China, is a traditional Mongolian medicine herb. Two different solvents as water and methanol were used to extract AM, and their antioxidant capacity and inhibitory effects against key enzymes related to metabolic syndrome were assessed. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS and reducing power assays. In addition, the total phenolic content and total flavonoids content were quantificated and analyzed. Aqueous extract, having higher phenolic content (10.20 mg GAE/g DW) and flavonoid content (4.02 mg QE/g DW), showed better antioxidant and inhibitory effects against lipase and angiotensin-converting enzyme (ACE); as for α-glucosidase, the extract made by methanol showed better ability. In general, the aqueous extract of A. mongolicum Regel has the potential to be used as a functional food or nutraceutical in prevention and treatment of obesity and hypertension due to the high antioxidant and sound inhibitory potential against vital enzymes relevant to obesity and hypertension.

Identification and Antioxidant Activity of Flavonoids Extracted from Xinjiang Jujube (Ziziphus jujube Mill.) Leaves with Ultra-High Pressure Extraction Technology

In this study, the ultra-high pressure extraction (UHPE) conditions for obtaining the maximum flavonoid yield from Xinjiang jujube (Ziziphus jujuba Mill.) leaves (XJL) were optimized by response surface methodology (RSM). Box–Behnken design (BBD) was applied to evaluate the effects of four variables (extraction temperature, pressure, time and liquid-to-solid ratio) on flavonoid yield. The results showed that the optimal flavonoid yield (25.45 ± 0.21 mg/g) was derived at 50.0 °C, 342.39 MPa, 11.56 min, and a liquid-to-solid ratio of 43.95 mL/g. Eight compounds were tentatively identified and quantified as kaempferol and quercetin glycosides with UPLC-ESI-MS. Compared to ultrasound-assisted extraction (UAE), UHPE can obtain higher concentrations of total flavonoids and stronger DPPH and ABTS radical-scavenging activities in a much shorter time. Therefore, UHPE is an alternative to UAE for obtaining flavonoids from XJL, which may be an optional method for large-scale industrial flavonoid extraction from XJL.