Factors affecting extraction and evolution of phenolic compounds during red wine maceration and the role of process modelling

Effect of Cap Management Frequency on the Phenolic, Chromatic, and Sensory Composition of Cabernet Sauvignon Wines from the Central Coast of California over Two Vintages

Cabernet Sauvignon from the California Paso Robles AVA was processed with a contrasting array of cap management frequencies, consisting of punch-down (PD) frequencies (0, 1, 2, and 3 PD/day) over two vintages, one of which the fruit was harvested at two contrasting maturity levels. Wines followed with up to 3 years of bottle aging for basic and phenolic chemistry, and the wines of the second harvest of 2020 were submitted to sensory analysis. There were almost non-existent effects due to the frequency of punch downs on parameters such as ethanol, pH, titratable acidity, lactic acid, and glucose + fructose. In 2019, the chromatic differences between different PD regimes were subtle, and minor effects of the punch-down frequency were observed for tannins and total phenolics. During the early stages of alcoholic fermentation, higher levels of all anthocyanin classes were observed in 1 PD wines and the lowest levels in 0 PD wines. The anthocyanin content of the wines of the first harvest (unripe) was 27% higher than that of the wines of the second harvest (ripe), but these differences disappeared after 3 years of bottle aging irrespective of the vintage and harvest date. Acylated anthocyanins were preferentially lost during aging, especially in 2019 wines and, to a lesser extent, in 2020 wines. In 2020, the polymeric pigment content of the wines of the second harvest was higher than in the wines of the first harvest, with 3 PD wines showing higher polymeric pigments and yellow hues than 0 and 2 PD wines after 3 years of bottle aging. Sensory analysis of the second harvest of the 2020 wines showed that the wines of all four PD regimes were perceived as drying, signifying they were perceived as equally astringent, which is consistent with comparable tannin levels on said wines. The perception of bitterness increased with the frequency of punch downs; thus, 3 PD wines showed the highest bitterness perception. It was concluded that in sufficiently warm fermentations and small volumes, phenolic extraction occurs regardless of fruit maturity and under conditions of minimum mixing.

Leaching and evolution of anthocyanins and aroma compounds during Cabernet Sauvignon wine fermentation with whole-process skin-seed contact

This study explores the leaching and evolution of anthocyanins and aroma compounds during wine-making, using an industrial-scale vinification of Cabernet Sauvignon with whole-process skin-seed contact. The results indicated that compounds within the same class displayed similar evolutionary patterns during fermentation. The extraction of anthocyanins, C6 aldehydes, and β-damascenes occurred continuously during cold soak, accompanied by the conversion of C6 aldehydes into alcohols and hydrolytic release of glycosidic β-damascenone. During alcoholic fermentation, pyranoanthocyanins, polymeric pigments, esters, benzene compounds, higher alcohols, and acids were generated. The concurrent occurrence of malolactic fermentation and prolonged maceration led to aromas associated with lactic acid bacteria metabolism. Finally, a comparison between free-run wine and pressed wine revealed high concentrations of C6 compounds and polymeric pigments with flavanol dimers in the pressed wine. These results can be used as a reference to optimize the vinification process to enhance the red due and fruity aromas of the wine.

Major Active Metabolite Characteristics of Dendrobium officinale Rice Wine Fermented by Saccharomyces cerevisiae and Wickerhamomyces anomalus Cofermentation

Rice, supplemented with Dendrobium officinale, was subjected to cofermentation using Saccharomyces cerevisiae FBKL2.8022 (Sc) and Wickerhamomyces anomalus FBKL2.8023 (Wa). The alcohol content was determined with a biosensor, total sugars with the phenol-sulfuric acid method, reducing sugars with the DNS method, total acids and total phenols with the colorimetric method, and metabolites were analyzed using LC-MS/MS combined with multivariate statistics, while metabolic pathways were constructed using metaboAnalyst 5.0. It was found that the quality of rice wine was higher with the addition of D. officinale. A total of 127 major active substances, mainly phenols, flavonoids, terpenoids, alkaloids, and phenylpropanoids, were identified. Among them, 26 substances might have been mainly metabolized by the mixed-yeasts fermentation itself, and 10 substances might have originated either from D. officinale itself or from microbial metabolism on the newly supplemented substrate. In addition, significant differences in metabolite could be attributed to amino acid metabolic pathways, such as phenylalanine metabolism and alanine, aspartate, and glutamate metabolism. The characteristic microbial metabolism of D. officinale produces metabolites, which are α-dihydroartemisinin, alantolactone, neohesperidin dihydrochalcone, and occidentoside. This study showed that mixed-yeasts cofermentation and fermentation with D. officinale both could increase the content of active substances in rice wine and significantly improve the quality of rice wine. The results of this study provide a reference for the mixed fermentation of brewer's yeast and non-yeast yeasts in rice wine brewing.

Grape skin anthocyanin extraction from red varieties during simulated maceration: Influence of grape seeds and pigments adsorption on their surface

The impact of seeds on anthocyanin extraction from skins was assessed on four Italian red winegrape varieties presenting different anthocyanin profile. Grape skins were macerated alone or in presence of seeds for ten days in model solutions. Aglianico, Nebbiolo, Primitivo, and Sangiovese cultivars showed differences in the anthocyanin extraction rate, content, and profile. The presence of seeds did not significantly affect the anthocyanin content and forms extracted from skins and kept into solution, but it generally led to an increase in the polymerization rate. For the first time, anthocyanins adsorbed on seed surface have been quantified after maceration. The amount of anthocyanins retained by seeds was less than 4 mg/kg berries and it seems variety-dependent, with a possible role of seeds number and weight. Individual anthocyanin forms were adsorbed mainly according to their abundance in the solution, but cinnamoyl-glucoside anthocyanin forms showed a higher affinity with seed surface.

The importance of outlier rejection and significant explanatory variable selection for pinot noir wine soft sensor development

Sensory attributes are essential factors in determining the quality of wines. However, it can be challenging for consumers, even experts, to differentiate and quantify wines' sensory attributes for quality control. Soft sensors based on rapid chemical analysis offer a potential solution to overcome this challenge. However, the current limitation in developing soft sensors for wines is the need for a significant number of input parameters, at least 12, necessitating costly and time-consuming analyses. While such a comprehensive approach provides high accuracy in sensory quality mapping, the expensive and time-consuming studies required do not lend themselves to the industry's routine quality control activities. In this work, Box plots, Tucker-1 plots, and Principal Component Analysis (PCA) score plots were used to deal with output data (sensory attributes) to improve the model quality. More importantly, this work has identified that the number of analyses required to fully quantify by regression models and qualify by classification models can be significantly reduced. Based on regression models, only four key chemical parameters (total flavanols, total tannins, A_520nm^HCl, and pH) were required to accurately predict 35 sensory attributes of a wine with R² values above 0.6 simultaneously. In addition, for classification models to accurately predict 35 sensory attributes of a wine at once with prediction accuracy above 70%, only four key chemical parameters (A_280nm^HCl, A_520nm^HCl, chemical age and pH) were required. These models with reduced chemical parameters complement each other in sensory quality mapping and provide acceptable accuracy. The application of the soft sensor based on these reduced sets of key chemical parameters translated to a potential reduction in analytical cost and labour cost of 56% for the regression model and 83% for the classification model, respectively, making these models suitable for routine quality control use.

Yeast or water: producing wine with lower alcohol levels in a warming climate: a review

Climate change effects over the last century have seen grape wine growers being faced with earlier budburst and shorter seasons. One effect is higher sugar levels in the grape berries, resulting in wines with higher than typical alcohol concentrations. Winemakers, both in Australia and globally, need to reassess their wine making approaches to address the challenges associated with warmer drier conditions. This review focuses on two pre-fermentation approaches that address ethanol production during fermentation, so that wine makers can produce a wine with lower final alcohol levels at the same time as addressing any negative impacts on wine quality. First, microbiological yeast approaches are reviewed. This approach can reduce final alcohol levels in a treated wine between 0.2% v/v-3.7% v/v; however, diverse wine quality impacts can result, dependant on the microbiological yeast approach taken. Second, the pre-fermentation approach of water addition/substitution into a high sugar grape must is reviewed. To date, recent studies indicate that this 'water treatment' of musts approach is effective with respect to reducing final alcohol levels from between 0.6% v/v-5.9% v/v in the resultant wines, with less variation effects on final wine quality. It is noted that further studies for the 'water treatment' of high sugar musts approach are required to provide additional foundational data sets with respect to impacts on chemical, phenolic and sensory attributes of the final wine products, both within and across vintages. This is especially important as winemakers adapt their winemaking approaches in a changing climate. © 2022 Society of Chemical Industry.

Diffusion of phenolic compounds during a model maceration in winemaking: role of flesh and seeds

BACKGROUND

During red winemaking, diffusion of phenolic compounds from the grape berry cells into the liquid phase occurs simultaneously with the adsorption of the same compounds onto the pulp. In previous studies, we quantified the proportions of polyphenols diffusing from the skins and then assessed the amounts that can be fixed by the pulp. In this work, we added the impact of seeds, also present during vinification, by carrying out macerations in a model medium with the following berry compartments: skins, seeds, skins + seeds, skins + seeds + pulp.

RESULTS

Interestingly, the seeds alone released a rather high amount of polyphenols. As soon as they were in the presence of cell walls of skin/flesh, and/or anthocyanins, the concentration of seed tannins in the solution dropped dramatically, due to a combined effect of adsorption and/or precipitation and/or chemical reactions. The pulp certainly adsorbed tannins, but they also tended to shift the extraction equilibria, and it seems that more tannins could be extracted from skins and seeds when pulp was present. Polyphenol amounts extracted in model systems with skins + seeds + pulp were close to what was extracted in microvinification.

CONCLUSION

These model experiments reflect relatively well extraction during microvinification experiments and highlight the respective impact of the grape berry's different compartments in the wine's final phenolic composition as well as some of the mechanisms involved. © 2022 Society of Chemical Industry.

Impact of the variety on the adsorption of anthocyanins and tannins on grape flesh cell walls

BACKGROUND

During winemaking, after extraction from the skins, anthocyanins and tannins adsorb onto the pulp flesh cell walls. The present study aimed to quantify the amounts adsorbed and their impact on wine composition, the impact of variety and ethanol on adsorption, and whether the presence of anthocyanins plays a role and impacts tannin adsorption.

RESULTS

Anthocyanin and tannin fractions obtained by mimicking winemaking conditions were mixed with fresh flesh cell walls of two varieties: Carignan and Grenache. Adsorption isotherms were measured. Adsorption of tannins was higher with Carignan than with Grenache and decreased when the ethanol content increased. In comparison, anthocyanins were adsorbed in small amounts, and their mixing with tannins had no impact on their adsorption. The differences were related to differences in pulp cell wall composition, particularly in terms of extensins and arabinans.

CONCLUSION

Adsorption of tannins, which can reach 50% of the initial amount, depends on the pulp cell wall composition. This needs to be investigated further. © 2021 Society of Chemical Industry.

Optimisation of PLS Calibrations for Filtered and Untreated Samples towards In-Line Monitoring of Phenolic Extraction during Red-Wine Fermentations

Infrared spectroscopy provides an efficient, robust, and multivariate means to measure phenolic levels during red-wine fermentations. However, its use is currently limited to off-line sampling. In this study, partial least squares (PLS) regression was used to investigate the possibility of using spectral data from minimally pre-treated or untreated samples for the optimisation of prediction calibrations towards an in-line monitoring set-up. The evaluation of the model performance was conducted using a variety of metrics. Limits of detection and quantification of the PLS calibrations were used to assess the ability of the models to predict lower levels of phenolics from the start of fermentation. The calibrations were shown to be useful for the quantification of phenolic compounds and phenolic parameters with minimal or no sample pre-treatment during red-wine fermentation. Upon evaluation of performance, the calibrations built for attenuated-transmission Fourier-transform mid-infrared (ATR-FT-MIR) and diffuse-reflectance Fourier-transform near-infrared (DR-FT-NIR) were shown to be the most suitable spectroscopy techniques for eventual application in an automated and in-line system with values for limits of detection and quantification being suitable for the entire duration of fermentation.

An Evaluation of Food Safety Performance in Wineries

Wine production has food safety hazards. A Hazard Analysis Critical Control Point (HACCP) system makes it possible to identify, evaluate, and control significant food safety hazards throughout the wine production process. The Prerequisites Programs (PPRs) and HACCP performance in Protected Denomination of Origin “Vinos de Madrid” wineries were analyzed. Winery performances were evaluated for every critical control point (CCPs) in each winemaking process stage, including their implementation of PPR and HACCP principles. This study was developed through a survey of 55 questions divided into 11 sections, and it was conducted on a sample of 21 wineries. The results revealed that the CCPs worst performance level are for the control of metals (Cd, Pb, As) in grapes and fungicides or pesticide control in the harvest reception. A total of 91.5% of the wineries had implemented a prerequisites program (PPRs), regardless of their annual wine production. However, there was variability in the type of prerequisite plans, training, level of knowledge of operators, and annual budget allocation. Three out of four wineries had an HACCP, although corrective action procedures and verification procedures had the lowest and the worst HACCP practical implementation. The significant barriers for HACCP performance in wineries are linked with a lack of food safety staff training, low involvement of all staff in food safety tasks, and poor application of CCP chemical and microbiologic control methods.

Two-Step PEF Processing for Enhancing the Polyphenol Concentration and Decontaminating a Red Grape Juice

This study’s aim is to evaluate Pulsed Electric Fields (PEF) technology as an alternative method for the processing of red grape juice. For this purpose, two PEF treatments were applied: first to grapes for polyphenol enrichment of the juice, and subsequently for microbial decontamination of the obtained juice. Juice obtained from PEF-treated grapes (5 kV/cm, 63.4 kJ/kg) had the polyphenol content 1.5-fold higher and colour intensity two times higher of control juices by spectrophotometric measurement (p ≤ 0.05). A subsequent decontamination treatment by PEF (17.5 kV/cm and 173.6 kJ/kg) achieved inactivation of the present microbiota (yeasts, moulds, and vegetative mesophilic bacteria) below detection level (<30 CFU/mL). Furthermore, PEF-treated juices were microbiologically stable up to 45 days, even at abusive refrigeration storage temperatures (10 °C). PEF juice quality and sensory characteristics were similar to a fresh juice; they were neither affected by the PEF decontamination treatment, nor by storage time and temperature. Results obtained in this study demonstrate the considerable potential of PEF for the production of a polyphenol-enriched and microbially stabilized red grape juice as a unique and sustainable alternative for the juice industry, while avoiding enzymatic and heat treatments.

Influence of keeping the calyces during fermentation on physicochemical and sensory properties of Hibiscus sabdariffa wines

Hibiscus (Hibiscus sabdariffa) wines are usually made through the fermentation of its calyces extracts. However, the exhausted calyces could still contain a considerable amount of extractable bioactive compounds. This work analyzed the effect of keeping the hibiscus calyces during fermentation on the physicochemical and sensory characteristics and acceptance of its wines. Hibiscus wines Filtered-Ch and Filtered-C were generated by fermentation of filtered musts of China and Colima varieties, respectively, while Unfiltered-Ch and Unfiltered-C were obtained by fermentation of musts from calyces that were kept for 120 days. Unfiltered-C and Unfiltered-Ch wines had higher contents of total monomeric anthocyanins (32.5 mg/L in Unfiltered-C and 48.5 mg/L in Unfiltered-Ch), condensed tannins (around 200 mg_CE/L), total phenolic compounds (800 mg_GAE/L), and antioxidant activity (8.4-8.8 mM_TE/L), as well as a higher concentration of tartaric, citric and malic acids (0.26, 0.32 and 2.25 g/L, respectively) than Filtered-C and Filtered-Ch wines (P < 0.05). Moreover, Unfiltered-C and Unfiltered-Ch wines had darker red colors, evidenced by lower lightness, chroma and hue values, than those observed in Filtered-C and Filtered-Ch wines (P < 0.01). Furthermore, Unfiltered-Ch and Unfiltered-C wines were more appreciated, having a more intense taste and smell according to the descriptions obtained from consumers by applying the Check-All-That-Apply technique. Sensory attributes observed in hibiscus wines were statistically correlated with the physicochemical characteristics. Keeping hibiscus calyces during fermentation allows for the production of wines with acceptable sensory characteristics and a higher concentration of bioactive compounds than producing wines from filtered musts.

Identification of Tentative Traceability Markers with Direct Implications in Polyphenol Fingerprinting of Red Wines: Application of LC-MS and Chemometrics Methods

This study investigated the potential of using the changes in polyphenol composition of red wine to enable a more comprehensive chemometric differentiation and suitable identification of authentication markers. Based on high performance liquid chromatography-mass spectrometry (HPLC-MS) data collected from Feteasca Neagra, Merlot, and Cabernet Sauvignon finished wines, phenolic profiles of relevant classes were investigated immediately after vinification (Stage 1), after three months (Stage 2) and six months (Stage 3) of storage, respectively. The data were subjected to multivariate analysis, and resulted in an initial vintage differentiation by principal component analysis (PCA), and variety grouping by canonical discriminant analysis (CDA). Based on polyphenol common biosynthesis route and on the PCA correlation matrix, additional descriptors were investigated. We observed that the inclusion of specific compositional ratios into the data matrix allowed for improved sample differentiation. We obtained simultaneous discrimination according to the considered oenological factors (variety, vintage, and geographical origin) as well as the respective clustering applied during the storage period. Subsequently, further discriminatory investigations to assign wine samples to their corresponding classes relied on partial least squares-discriminant analysis (PLS-DA); the classification models confirmed the clustering initially obtained by PCA. The benefits of the presented fingerprinting approach might justify its selection and warrant its potential as an applicable tool with improved authentication capabilities in red wines.

Commercial Mannoproteins Improve the Mouthfeel and Colour of Wines Obtained by Excessive Tannin Extraction

In the production of red wines, the pressing of marcs and extended maceration techniques can increase the extraction of phenolic compounds, often imparting high bitterness and astringency to finished wines. Among various oenological products, mannoproteins have been shown to improve the mouthfeel of red wines. In this work, extended maceration (E), marc-pressed (P), and free-run (F) Sangiovese wines were aged for six months in contact with three different commercial mannoprotein-rich yeast extracts (MP, MS, and MF) at a concentration of 20 g/hL. Phenolic compounds were measured in treated and control wines, and sensory characteristics related to the astringency, aroma, and colour of the wines were studied. A multivariate analysis revealed that mannoproteins had a different effect depending on the anthocyanin/tannin (A/T) ratio of the wine. When tannins are strongly present (extended maceration wines with A/T = 0.2), the MP conferred mouthcoating and soft and velvety sensations, as well as colour stability to the wine. At A/T = 0.3, as in marc-pressed wines, both MF and MP improved the mouthfeel and colour of Sangiovese. However, in free-run wine, where the A/T ratio is 0.5, the formation of polymeric pigments was allowed by all treatments and correlated with silk, velvet, and mouthcoat subqualities. A decrease in bitterness was also obtained. Commercial mannoproteins may represent a way to improve the mouthfeel and colour of very tannic wines.

Using untargeted metabolomics to profile the changes in roselle (Hibiscus sabdariffa L.) anthocyanins during wine fermentation

In this study, an UHPLC-QE-MS approach in combination with multivariate statistical analyses was used to investigate the metabolic profiles, especially the anthocyanin profiles, during the fermentation of roselle wine. Overall, a large number of different metabolites (e.g., phenols, lipids, carbohydrates, amino acids and peptides, and others) were identified in the fermentation processes. Eight anthocyanin metabolites were identified in roselle wine for the first time, of which six were identified in the main fermentation process and two in the post-fermentation process. In addition, we identified several metabolic pathways during the fermentation process, and the metabolic pathways of anthocyanins in roselle wine are mainly related to flavonoid biosynthesis and to anthocyanin biosynthesis. These findings are expected to be useful for further studies on wine chemistry and yeast metabolism.

Optimal Control Applied to Oenological Management of Red Wine Fermentative Macerations

The management of wineries for industrial red winemaking is limited by the capacity and availability of fermentation tanks over the harvest season. The winemakers aim to optimize the wine quality, the fermentative maceration length, and the fermentation tank’s productive cycle simultaneously. Maceration in varietal wine production is carried out until a specific sugar content (digging-out point) is attained, finishing before alcoholic fermentation. Winemakers have found that by trial and error handling of the digging-out point, they can improve the winery capacity and production cost. In this work, we develop an optimal control problem for managing the digging-out point considering two objectives associated with process efficiency and costs. A good compromise between these objectives was found by applying multi-criteria decision-making (MCDM) techniques and the knee point. Two control strategies were compared: free nutrition and traditional nutrition. TOPSIS and LINMAP algorithms were used to choose the most suitable strategy that coincided with the knee point. The preferred option was nitrogen addition only at the beginning of fermentation (6.6–10.6 g/hL of DAP) and a high fermentation temperature (30 °C), yielding the desired digging-out point with a small error (6–9 g/L).

Impact of grape variety, berry maturity and size on the extractability of skin polyphenols during model wine-like maceration experiments

BACKGROUND

Skin cell walls modulate anthocyanin and tannin extraction from grape skins. However, relationships between the composition of alcohol-insoluble cell wall solids (AIS) and extraction are still unclear. Our objectives were to characterize the impact of variety, berry size and ripeness on skin AIS composition (polysaccharides, proteins) and polyphenol extraction during maceration.

RESULTS

Grape skin composition and its impact on polyphenol extraction was compared for two varieties - Carignan and Grenache - with skins of berries sorted according to their size and density. Extractions were performed under model wine-like maceration conditions. Fresh skins had similar content of polymeric tannins, but strongly differed in their anthocyanin content (higher in Carignan and in the ripest berries) and composition (higher proportions in coumaroylated anthocyanins in Carignan). Anthocyanin extraction was proportionally much higher in Grenache, which was not just related to the Carignan's higher levels in coumaroylated anthocyanins. Chemical reactions decreased anthocyanin concentrations in solution for both varieties. Tannin extraction for Grenache was slightly higher and faster than for Carignan. Skin AISs differed slightly between the two varieties in their carbohydrate composition and protein content, but not between modalities. Polyphenol analyses in the precipitates evidenced at the end of the maceration and in residual skins highlighted differences between the two varieties and between berries with different ripeness.

CONCLUSION

Structural information on the cell wall network and on its changes during maceration, along with a better understanding of the chemical reactions of anthocyanins and tannins, is needed to better relate grape and wine polyphenol composition. © 2020 Society of Chemical Industry.

Chemical composition of dried Stevia rebaudiana Bertoni leaves and effect of ultrasound-assisted extraction on total steviosides content in extract

Introduction: Steviol stevioside, which has been used in the production of food products as a low-calorie sweeten, is one of the main glycoside groups in the leaves of the Stevia plants. It is useful for human health.

Objective: The main objection of the present study was to find out some major chemical compositions of the dried Stevia rebaudiana Bertoni leaves and an effective, affordable, and environmentally friendly method to reach the high extraction yield of total steviosides from them. Therefore, a novel extraction, ultrasound-assisted extraction (UAE), was carried out to extract total steviosides from dried leaves of S. rebaudiana plant with ethanol of 70% (v/v) as a solvent.

Methods: Some major chemical compositions of the dried S. rebaudiana leaves were analyzed according to the AOAC (Association of Official Analytical Chemists) and total steviosides content (TSC) was measured by anthrone-sulphuric acid colorimetric assay with main influencing factors including material/solvent ratio, extraction temperature, and extraction time.

Results: The results referred that some chemical compounds such as protein, lipid, fibre, sugar, etc. existed in this material. The best extraction conditions were the sample/solvent ratio of 1:100 (g/ml), extraction temperature of 75oC, and extraction time of 30 min.

Conclusion: The highest amount of total steviosides content of 8.894 % was obtained at the optimal extraction condition. Consequently, these results demonstrated that the parameters of UAE were applied successfully for producing total glycosides.

Influence of Temperature during Pre-Fermentative Maceration and Alcoholic Fermentation on the Phenolic Composition of 'Cabernet Sauvignon' Wines

This study presents the effects of different working temperatures on the transfer of compounds during the pre-fermentative and fermentative stages of the wine making process with ‘Cabernet Sauvignon’ grapes. Two different procedures have been evaluated. Firstly, the pre-fermentative maceration of the crushed grapes at two different temperatures (20 °C and 10 °C). Then, the alcoholic fermentation under two different sets of conditions, the fermentation at a constant temperature of 20 °C and the fermentation under a positive temperature gradient from 10 to 20 °C. According to the experimental results, the phenolic contents (total phenolics, total anthocyanins, and total tannins) were mainly conditioned by the fermentation temperature, however the pre-fermentative conditions also affected the content levels of these compounds. Furthermore, the use of a fermentation temperature gradient improved the organoleptic characteristics of the wines. However, the color was not as stable as that of wines produced through fermentation at a higher constant temperature. Consequently, the implementation of a temperature gradient during the alcoholic fermentation process is recommended and a longer period at high temperature over the last phase of the process would be desirable to obtain aromatic wines with the desirable color stability.

Peptides in Brewed Wines: Formation, Structure, and Function

The traditional low-alcoholic beverages, such as grape wine, sake, and rice wine, have been consumed all over the world for thousands of years, each with their unique methods of production that have been practiced for centuries. Moderate consumption of wine is generally touted as beneficial for health, although there is ongoing debate for the responsible components in wine. In this review, the structural and functional characteristics, the formation mechanisms, and their health-promoting activities of peptides in three brewed wines, grape wine, Chinese rice wine (also called Chinese Huangjiu or Chinese yellow wine), and Japanese sake, are discussed. The formation of peptides in wine imparts sensorial, technological, and biological attributes. Prospects on future research, with an emphasis on the peptide characterization, formation mechanism, physiological activity, and molecular mechanisms of action, are presented.

Bio-Protection as an Alternative to Sulphites: Impact on Chemical and Microbial Characteristics of Red Wines

In wine, one method of limiting the addition of sulphites, a harmful and allergenic agent, is bio-protection. This practice consists of the early addition of microorganisms on grape must before fermentation. Non-Saccharomyces yeasts have been proposed as an interesting alternative to sulphite addition. However, scientific data proving the effectiveness of bio-protection remains sparse. This study provides the first analysis of the chemical and microbiological effects of a Metschnikowia pulcherrima strain inoculated at the beginning of the red winemaking process in three wineries as an alternative to sulphiting. Like sulphiting, bio-protection effectively limited the growth of spoilage microbiota and had no influence on the phenolic compounds protecting musts and wine from oxidation. The bio-protection had no effect on the volatile compounds and the sensory differences were dependent on the experimental sites. However, a non-targeted metabolomic analysis by FTICR-MS highlighted a bio-protection signature.

Non-Targeted Metabolite Profiles and Sensory Properties Elucidate Commonalities and Differences of Wines Made with the Same Variety but Different Cultivar Clones

Grapes, one of the oldest agricultural crops, are cultivated to produce table fruits, dried fruits, juice, and wine. Grapevine variety is composed of clones that share common morphological traits. However, they can differ in minor genetic mutations which often result in not only notorious morphological changes but also in other non-visible sensorial distinctive attributes. In the present work, we identified three Vitis vinifera cv. Pinot noir clones grown under identical field conditions that showed different grape cluster types. Here, sensorial analysis together with non-targeted metabolite profiles by Ultra High performance Liquid Chromatography (UPLC) couples to Ultra High Resolution Mass Spectrometry (FT-ICR-MS) of wines elaborated from the three different grape cluster types was studied with the aim of (i) finding sensorial differences among these three types of wines, and, if there were, (ii) determining the molecular features (metabolites) associated with these sensorial attributes by a multivariate statistical approach.

Response surface optimization of phenolic compounds from jabuticaba (Myrciaria cauliflora [Mart.] O.Berg) seeds: Antioxidant, antimicrobial, antihyperglycemic, antihypertensive and cytotoxic assessments

The aim of this study was to evaluate the effects of different solvents and maximize the extraction of bioactive compounds from jabuticaba (Myrciaria cauliflora) seeds. In general, the solvent system composed of water and propanone (52:48 v/v) modified the extract polarity and increased extraction yield of bioactive compounds. The optimized extract presented antioxidant capacity measured by different chemical and biological assays. The optimized extract exerted antiproliferative and cytotoxic effects against A549 and HCT8 cells, antimicrobial and antihemolytic effects, inhibited α-amylase/α-glucosidase activities and presented in vitro antihypertensive effect. Nonetheless, the optimized extract showed no cytotoxicity in a human cell model (IMR90). Vescalagin, castalagin and ellagic acid were the major phenolic compounds in the optimized extract. Our results show that jabuticaba seed may be a potential ingredient for the development of potentially functional foods.

Evolution of Polyphenolic Compounds and Sensory Properties of Wines Obtained from Grenache Grapes Treated by Pulsed Electric Fields during Aging in Bottles and in Oak Barrels

The evolution of polyphenolic compounds and sensory properties of wines obtained from Grenache grapes, either untreated or treated with pulsed electric fields (PEF), in the course of bottle aging, as well as during oak aging followed by bottle aging, were compared. Immediately prior to aging in bottles or in barrels, enological parameters that depend on phenolic extraction during skin maceration were higher when grapes had been treated with PEF. In terms of color intensity, phenolic families, and individual phenols, the wine obtained with grapes treated by PEF followed an evolution similar to untreated control wine in the course of aging. Sensory analysis revealed that the application of a PEF treatment resulted in wines that are sensorially different: panelists preferred wines obtained from grapes treated with PEF. Physicochemical and sensory analyses showed that grapes treated with PEF are suitable for obtaining wines that require aging in bottles or in oak barrels.

Comparison of conventional extraction technique with ultrasound assisted extraction on recovery of phenolic compounds from lemon scented tea tree (Leptospermum petersonii) leaves

Leptospermum petersonii is a native Australian medicinal and aromatic plant. This study was designed to evaluate the influence of solvents and ultrasound-assisted extraction (UAE) parameters including time, temperature, and sonication power on the yield of phenolic compounds and antioxidant capacity from lemon scented tea tree leaves. Extraction efficiency of the optimal UAE conditions were compared with that of shaking water bath technique. The results show that extraction solvents significantly affect extraction yield of phenolic compounds and antioxidant properties, and 50% acetone in water was found to be the most suitable solvent. The UAE optimal conditions were 60 min, 50 °C and sonication power of 200 W. Under these optimal conditions the yields of total phenolics, flavonoids, proanthocyanidins were 98.91 ± 1.20 (mg GAE/g DW), 76.12 ± 0.79 (mg CE/g DW), 117.71 ± 2.18 (mg CE/g DW), respectively. Antioxidant properties from four assays including FRAP, CUPRAC, ABTS and DPPH were 581.29 ± 14.23, 5534.87 ± 19.56, 1636.18 ± 4.11, and 889.29 ± 20.68 (mM TE/g DW) respectively. The UAE extraction technique was found to be more efficient in extraction of total phenolics and antioxidant capacity in comparison with conventional shaking water bath extraction. This study also observed a strong correlation between phenolic compounds and antioxidant capacities. All three phenolic compound groups (TPC, TFC, and Pro.A) were contributed to both free radical scavenging and ion reducing properties in the lemon scented tea tree leaves extract. However, the order of the phenolic groups was TPC > Pro.A > TFC for antioxidant properties.

Role of anthocyanin traits on the impact of oenological tannins addition in the first stage of red winegrape skin simulated maceration

In winemaking, exogenous tannins are added before maceration to improve future wine color characteristics derived from extracted grape anthocyanins. The study aimed to investigate the relation between different grape varieties, selected according to their anthocyanin profile, and the effect of five exogenous tannin formulations differing in origin and chemical features. Anthocyanin content, polymeric pigments, and color traits were assessed during a 72-hour skin simulated maceration. Grape skin-derived tannins increased color intensity (up to one unit) and polymeric pigments formation (up to 6.5%) in malvidin-prevalent Merlot and Cabernet sauvignon, with different extent depending on the anthocyanin richness. Grape seed-derived and ellagic formulations favored the pigment polymerization, the first in Nebbiolo and Sangiovese (up to 8.2%), which are characterized by high ratios of disubstituted anthocyanins, and the latter in malvidin-rich Syrah and Aglianico (up to 5%). A positive effect of quebracho regarded the defense of anthocyanin forms, particularly in Sangiovese and Nebbiolo.

Analysis of factors related to browning of Dangshan pear (Pyrus spp.) wine

The effects of different dissolved oxygen concentrations (DOC) on the browning degree, amino acids, total phenols, reducing sugars, polyphenoloxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL) of pear wine, and the relationship between various quality indicators and browning degree were investigated. Dynamic model fitting analysis of the changes of physiochemical indicators of pear wine in the storage process were performed. The importance of the physiochemical indicators effect on the browning of pear wine during the storage process was analyzed by OPLS (orthogonal partial least squares discriminant analysis), and the effect of dissolved oxygen on the browning of pear wine was systematically revealed. The results showed that dissolved oxygen, total phenols and amino acids had the greatest influence on the browning degree of pear wine. It provided a theoretical basis for revealing the browning mechanism and inhibiting the browning of pear wine.

Camu-camu seed (Myrciaria dubia) - From side stream to anantioxidant, antihyperglycemic, antiproliferative, antimicrobial, antihemolytic, anti-inflammatory, and antihypertensive ingredient

Camu-camu (Myrciaria dubia) seeds are discarded without recovering the bioactive compounds. The main aim of the present work was to optimise the solvent mixture to extract higher total phenolic content and antioxidant capacity of camu-camu seeds. The optimised solvent system increased the extraction of phenolic compounds, in which vescalagin and castalagin were the main compounds. The optimised extract displayed antioxidant capacity measured by different chemical and biological assays, exerted antiproliferative and cytotoxic effects against A549 and HCT8 cancer cells, antimicrobial effects, protected human erythrocytes against hemolysis, inhibited α-amylase and α-glucosidase enzymes and presented in vitro antihypertensive effect. Additionally, the optimized extract inhibited human LDL copper-induced oxidation in vitro and reduced the TNF-α release and NF-κB activation in macrophages cell culture. Thus, the use of camu-camu seed showed to be a sustainable way to recover bioactive compounds with in vitro functional properties.

A combined phenolic extraction and fermentation reactor engineering model for multiphase red wine fermentation

Red wine production begins with a simultaneous fermentation and solid-phase extraction process. Red wine color and mouthfeel is the result of the extraction of phenolics from grape skins and seeds during fermentation, where extraction is a strong function of temperature and ethanol concentration. During fermentation, grape solids form a porous "cap" at the top of the fermentor, resulting in a heterogeneous fermentation system with significant temperature and concentration gradients. In this work, we present a spatial, time-variant reactor engineering model for phenolic extraction during red wine fermentation, incorporating fermentation kinetics, mass transfer, heat transfer, compressible fluid flow, and phenolic extraction kinetics. The temperature and ethanol concentration profiles predicted by this model allow for the calculation of phenolic extraction rates over the course of fermentation. Phenolic extraction predictions were validated against prior experimental data to good agreement and compared to a well-mixed model's predictions to show the utility of a spatial model over well-mixed models.

Thermal and Non-Thermal Physical Methods for Improving Polyphenol Extraction in Red Winemaking

Maceration-fermentation is a critical stage in the elaboration of high-quality red wine. During this stage, the solid parts of the grape berries remain in contact with the fermenting must in order to extract polyphenols mainly located in the grape skin cells. Extracted polyphenols have a considerable impact on sensory properties (color, flavor, astringency, and bitterness) and on the aging behavior of red wine. In order to obtain wines with a sufficient proportion of those compounds, long maceration times are required. The presence of the solid parts of the grapes during red wine fermentation involves several problems for the wineries such as production capacity reduction, higher energy consumption for controlling the fermentation temperature and labor and energy consumption for periodically pump the grape must over the skin mass. Physical techniques based on heating such as thermovinification and flash expansion are currently being applied in wineries to improve the extraction of polyphenols and to reduce maceration time. However, these techniques present a series of problems derived from the heating of the grapes that affect wine quality. A series of recent studies have demonstrated that non-thermal innovative technologies such as pulsed electric fields (PEF) and ultrasound may represent effective alternatives to heating for assisting polyphenol extraction. In terms of general product quality and energetic requirements, this review compares these thermal and non-thermal physical technologies that aim to reduce maceration time.

Chemical consequences of extended maceration and post-fermentation additions of grape pomace in Pinot noir and Zinfandel wines from the Central Coast of California (USA)

Pinot noir and Zinfandel wines were produced with traditional maceration (Control), and extended maceration for one (1 month-EM), and six months (6 months-EM). Addition of an extra amount of pomace during EM was also evaluated through a treatment referred to as Double pomace. The application of EM and Double pomace decreased the chromatic as well as the anthocyanin and anthocyanin-derived pigment composition of the wines. Large polymeric pigments were favored in EM and Double pomace wines, but the total polymeric pigment content was not improved by any of the winemaking treatments. The 6 months-EM wines showed a 13-fold (Pinot noir) and a 1.6-fold increase (Zinfandel) in tannins, respectively, relative to Control wines. However, the 1 month-EM and Double pomace treatments did not affect tannin levels, suggesting that in these wines, the extraction of tannins during EM may depend upon desorption of previously extracted tannins during extended contact time.