Stages Of Winemaking Research Articles

Non-Thermal Technology Approaches to Improve Extraction, Fermentation, Microbial Stability, and Aging in the Winemaking Process

Research into non-thermal wine processing technologies is constantly evolving due to the increasing trend towards high-quality, minimally processed, and preservative-free wines. Technologies such as high-power ultrasound, high hydrostatic pressure, pulsed electric field, ultra-high pressure homogenization, and, more recently, cold plasma are some of the best examples currently being explored. This article provides an overview of the latest scientific research into these five non-thermal technologies and their current status in relation to winemaking. By exploring the potential applications of these technologies, it becomes possible to enhance extraction, shorten maceration time, inactivate microorganisms and oxidative enzymes, reduce the addition of chemical additives, accelerate aging, improve wine quality, and much more. However, further experiments are necessary to better comprehend the short- and long-term impacts on the overall quality of the wines produced, especially in terms of sensory characteristics and consumer acceptance. Optimizing processing conditions and scaling up are also of paramount importance to ensure better performance of these technologies at the various stages of winemaking. Additionally, a combined technologies approach has been highlighted as one of the future directions to overcome the limitations of processing with a single technology.

The use of a specific glutathione-rich inactivated yeast to protect organic Catarratto grape must and wine from oxidation in the pre-fermentative phase

This study aimed to investigate the effects of using a specific glutathione-rich inactivated yeast (GIY) during the pre-fermentative stages of winemaking. The antioxidant properties of GIY were evaluated both alone and in combination with a selected strain of Metschnikowia pulcherrima, at various grape pressing stages. The assessment included measuring soluble oxygen levels and color browning in the musts. Additionally, the impact of different oenological protocols on the final aromatic profile of the wines was assessed through volatile organic compounds (VOCs) and sensory analysis. The results showed that inoculating M. pulcherrima during the pre-pressing phase, followed by GIY addition during the post-pressing stage, effectively reduced O2 uptake (1.49 mg/L) and minimized browning (0.093 OD at 420 nm) during the pre-fermentative phase. Furthermore, the protocol involving GIY addition during pressing resulted in higher concentrations of specific compounds associated with fruity and floral aromas, such as ethyl octanoate (26.03 mg/L) and ethyl decanoate (26.87 mg/L). Sensory evaluations confirmed that all treatments had no off-odours or off-flavours, but the M. pulcherrima and GIY combination received the highest scores for smoothness and colour attributes. In conclusion, GIY treatments offer a promising alternative to enhance wine colour and mitigate oxidation effects, potentially reducing the reliance SO2 in wine production.

Dosing oxygen from the early stages of white winemaking: Effect on oxidation–reduction potential, browning stability, volatile composition, and sensory properties

This study investigated the effect of controlled oxygen addition during alcoholic fermentation (4 mg/L, at 2nd, 4th, 6th, 10th, 14th, 16th, 20th day) and aging on lees (2 mg/L, every 15 days for 3 months) in a stainless-steel tank for white wine production from a nearly neutral grape. Under less reductive conditions (Ox), alcoholic fermentation was completed in 27 days, whereas one extra week was required under more reductive conditions (no-Ox). The greatest amount of dissolved oxygen in Ox wine triggered the increase of redox potential (EH) starting from the end of alcoholic fermentation and throughout aging (169 and 150 mV in Ox and no-Ox wine, respectively), also improving the wine resistance to browning. Oxygen addition from the early stages of winemaking significantly modulated volatile composition and sensory attributes, which may contribute to the diversification of wine style.

Influence Evaluation of Enzyme Treatments on Aroma Profile of White Wines

Improving aroma profile represents one of the principal goals in winemaking. This paper focuses to evaluate the influence of enzymes applied before alcoholic fermentation of Fetească regală and Sauvignon blanc wines, even if most studies analyze their use in different winemaking stages. Fetească regală wines are described by higher proportions (1.07–4.28%) of ethyl octanoate (exotic fruits), 3-methylbutyl acetate (pear, banana), hexanoic acid (creamy, phenolic, exotic fruits), propan-2-yl acetate (ripe fruits, banana), and ethyl decanoate (floral, fruity, woody), while Sauvignon blanc wines are distinguished by significant proportions (2.77–42.15%) of 3-methylbutan-1-ol (exotic fruits), acetic acid (vegetal, sour), 1-phenylethanol (floral, honey), and diethyl butanedioate (fruity, floral). Variables as 3-methylbutyl acetate-ethyl decanoate, ethyl decanoate-hexanoic acid (r > 0.8) showed proportional levels in Fetească regală wines. In Sauvignon blanc samples, positive correlations were observed for 2-ethyl hydroxypropanoate-diethyl butanedioate or 2,3-butanediol-ethyl 4-hydroxybutanoate (r > 0.7). Data confirmed a significant influence of enzymes on wine’s aroma profile (p < 0.05). The higher proportions of the most volatile compounds were obtained in samples treated with pectinases, for both varieties. In correlation with the sensory analysis, these variants showed the lowest intensity for negative descriptors such as phenolic sensation, the mineral or bitter taste, demonstrating that pectinases can give more acceptable results regarding the sensory perception compared to β-glycosidases.

Modulating a wine profileModulating a wine profile via an innovative use of vine-shoots

The chemical composition of vine-shoots is characterised by oenological compounds with high added value, which could contribute to the sensory profile of wines. In this study, toasted vine-shoots from two varieties were used in two different formats, granules and chips, and added to wine at different winemaking stages. The results show that oenological additives in the form of vine-shoots can modulate the chemical composition of wines, and therefore their quality, by enhancing their varietal and woody aromas; thus connecting viticulture and oenology and creating a new concept: circular viticulture.

The effect of pulsed electric fields pre-treatment on the volatile and phenolic profiles of Merlot grape musts at different winemaking stages and the sensory characteristics of the finished wines

This study investigated the effect of pulsed electric fields (PEF) applied at different electric field strengths (up to 41.5 kV/cm) and energy inputs (up to 49.4 kJ/kg) on the volatile and phenolic profiles of Merlot grapes at different stages of winemaking. Immediately after PEF treatment, greater amounts of anthocyanins and phenolics (e.g., catechin) were extracted while 2-hexenal (green aroma) was detected in lower concentrations in PEF-treated musts. At completion of alcoholic and malolactic fermentations, high-energy PEF treatment generally produced wines with increased anthocyanins, stilbenoids, hydroxycinnamic and hydroxybenzoic acids. A trained sensory panel assessed the sensory attributes of the finished wines using descriptive analysis. It was found that those Merlot wines vinified with PEF-treated grapes possessed higher intensities of blackcurrant flavour and odour. The intensity of spice flavour in the Merlot wines also differed significantly between the wines. Overall, PEF treatment has the capability to provide winemakers the means to tailor the extraction of phenolic compounds towards the creation of red wines with distinct sensory characteristics.

Population Dynamics and Yeast Diversity in Early Winemaking Stages without Sulfites Revealed by Three Complementary Approaches

Nowadays, the use of sulfur dioxide (SO2) during the winemaking process is a controversial societal issue. In order to reduce its use, various alternatives are emerging, in particular bioprotection by adding yeasts, with different impacts on yeast microbiota in early winemaking stages. In this study, quantitative-PCR and metabarcoding high-throughput sequencing (HTS) were combined with MALDI-TOF-MS to monitor yeast population dynamic and diversity in the early stages of red winemaking process without sulfites and with bioprotection by Torulaspora delbrueckii and Metschnikowia pulcherrima addition. By using standard procedures for yeast protein extraction and a laboratory-specific database of wine yeasts, identification at species level of 95% of the isolates was successfully achieved by MALDI-TOF-MS, thus confirming that it is a promising method for wine yeast identification. The different approaches confirmed the implantation and the niche occupation of bioprotection leading to the decrease of fungal communities (HTS) and Hanseniaspora uvarum cultivable population (MALDI-TOF MS). Yeast and fungi diversity was impacted by stage of maceration and, to a lesser extent, by bioprotection and SO2, resulting in a modification of the nature and abundance of the operational taxonomic units (OTUs) diversity.

Determination of Iron, Copper and Zinc in the Wine by FAAS

Objectives: The purpose of this paper has been to determine quantitatively the presence of some heavy metals (Fe, Cu and Zn) which are of particular importance for the wine quality and human health. A total of 41 samples have been analyzed during different stages of winemaking. Methods: The determination of heavy metals is done by analytical technique known as Flame Atomic Absorption Spectroscopy (FAAS). The limit set by the EU directive EC 606/2009 and International Office of Vine and Wine (OIV) has been taken as reference values. Results and Discussion: None of the analyzed samples has exceeded the limits set by the EU and OIV, excluding the type of white wine known as Rhine Riesling. In this sample the Cu concentration exceeds several times the permissible values. Findings: It has been observed that heavy metals immediately after the alcoholic fermentation process probably continue to remain even for a while in the upper part until wine sediment forms at the bottom of the tank. A higher concentration of heavy metals was observed in the samples taken from the bottom of the wine tank. Conclusion: The analyzed wines samples do not pose a risk in the future to human health. Doi: 10.28991/esj-2020-01240 Full Text: PDF

The impact of carbohydrate-active enzymes on mediating cell wall polysaccharide-tannin interactions in a wine-like matrix.

Tannins are present in grape skins and seeds from where they are transferred into the must-wine matrix during the maceration stages of winemaking. However, tannin transfer is often incomplete. This could be due, among other reasons, to tannins becoming bound to grape cell wall polysaccharides, including soluble polymers, which are released during vinification and are present in high concentrations in the must/wine. The use of cell wall deconstructing enzymes offers the possibility of reducing these interactions, releasing more tannins into the final wine. The main aim of this study was to evaluate the optimal addition (individually, in combination or sequentially) of hydrolytic enzymes that would prevent tight polysaccharide-tannin associations. The use of comprehensive microarray polymer profiling (CoMPP) methodology provided key insights into how the enzyme treatments impacted the grape cell wall matrix and tannin binding. The results demonstrated that polygalacturonase + pectin-lyase promoted the highest release of tannins into solution.

Quantification of toxic metals during different winemaking stages

Heavy metals in beverages can constitute serious problems to human health. Consumption of wine may contribute to the daily dietary intake of pollutants, especially of toxic (heavy) metals. These compounds are also known as priority pollutants due to their potential toxic effects, if concentrations are not kept under allowable limits. Many characteristics such as: quality, origin, aroma and health safety of wine are influenced by environmental and anthropogenic factors. Hence, the contamination of wine by priority pollutants may occur at different stages of vine-growing, due to the application of agricultural chemicals, or at different stage of winemaking and ageing, because of the extended contact of wine with winemaking equipment materials (aluminium, brass, glass, stainless steel and wood, etc.), or chemicals used for cleaning and sanitation. The aim of this study is to identify and quantify the heavy metal ions from red wines. A particular focus was attributed to Zn and Cd from destemming-pressing-filtration-bottling stages in Fetească neagră grape variety from Cotnari vine growing region of Romania. Results indicated that heavy metals were linked to diverse Zn and Cd sources and complexes during the winemaking processes. Concentration of Zn and Cd were generally higher in must than in wine, although heavy metals concentrations were lower than the limits recommended by the International Organization of Vine and Wine for human health safety.

A Novel Method for the Quantification of White Wine Mannoproteins by a Competitive Indirect Enzyme-Linked Lectin Sorbent Assay (CI-ELLSA).

Mannoproteins (MPs) are cell wall proteoglycans released in wine by yeast during fermentation and ageing on lees, a procedure used for the production of several wines to enrich them in these components with consequences from both a technological and sensory point of view. Given the significance that wine MPs have for wine quality, winemakers would welcome a simple and accurate method for their quantification, as this would allow them to have a better control of this aspect at different winemaking stages. This study develops and validates a novel, simple and accurate method for MPs quantification in white wines based on a competitive indirect enzyme-linked lectin sorbent assay (CI-ELLSA), using the highly mannosylated yeast invertase as the standard. The method utilizes the lectin concanavalin A (ConA) as the immobilized ligand for MPs, and peroxidase, an enzyme rich in mannose, as the competitor for ConA. After addition of the peroxidase substrate, the intensity of the signal produced by the activity of this enzyme (absorbance at 450 nm) is inversely proportional to the amount of mannosylated proteins in the sample. Results have been validated on several wine styles including still, sparkling and sweet wines.

Aroma modulation of Cabernet Gernischt dry red wine by optimal enzyme treatment strategy in winemaking

Cabernet Gernischt (CG) is a famous Chinese wine grape cultivar, the red wine of which is known for its green trait, especially when produced from grapes cultivated in regions with monsoon climate. To modify CG wine aroma, three enzyme preparations (H. uvarum extracellular enzyme, AR2000, and pectinase) were introduced in different winemaking stages with Saccharomyces cerevisiae. Free and bound aroma compounds in young wines were detected using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry, and aroma characteristics were quantified by trained panelists. Results showed that simultaneous inoculation of enzymes and yeasts improved wine aroma. Partial least-squares regression revealed that the green trait was due mainly to varietal compounds, especially C6 compounds, and could be partly weakened by fermentative compounds. Moreover, H. uvarum enzyme treatments enriched the acid fruit note of CG wine by enhancing the synergistic effect of varietal volatiles and certain fermentative compounds, such as esters and phenylethyls.

Management of mycotoxin contamination in stored grains by using ecological means

The state of art about data available on the toxicology and public concern for human exposure to ochratoxin A (OTA) is summarized, taking into account that the International Program on Chemical Safety/World Health Organisation has indicated a need for further study and evaluation with respect to human health potential. The fungi responsible for OTA presence in grapes and wine are defined, as are favorable meteorological conditions and cropping systems. A short description of efforts devoted to understanding the problem (i.e., research projects) is included. Grape processing has a significant impact on the OTA fate during the main stages of winemaking (crushing, maceration, alcoholic fermentation, malolactic fermentation, bottle, aging), and critical steps of the process have been identified. Postharvest strategies for the control of OTA in wines are focused on developments in the field of biological decontamination of OTA through the use of yeasts and lactic acid bacteria. Worldwide surveys have determined the main risk factors. The approach of risk assessment is described and data on wine consumption and related risk of OTA ingestion are reported with some comments on the effective related risk. The approach of a Decision Support System (DSS) is described, including the development of a predictive model, good agricultural practices, and good manufacturing practices to minimize OTA in grapes and wine.

Xanthan production on wastewaters from wine industry

Wine industry generates large volumes of wastewaters resulting from numerous cleaning operations that occur during the different stages of winemaking. Disposal of these effluents in the environment causes huge problems due to their high organic and inorganic load and seasonal variability. The bioconversion of winery wastewaters in valuable product, such as xanthan, is an important alternative to overcome environmental problems. In this research, the possibility of xanthan production using Xanthomonas campestris on blended wastewaters from different stages of white and rose wine production with initial sugar content of 50 g/L was investigated. In addition to the media parameters (content of sugars, total and assimilable nitrogen, phosphorus, total dissolved salts and apparent viscosity), raw xanthan yield and degree of sugar conversion into product were determined in order to examine the success of xanthan biosynthesis. In applied experimental conditions, xanthan yield of 20.92 and 30.64 g/L and sugar conversion into product of 40.23 and 60.73% were achieved on wastewaters from white and rose wine production, respectively. The results of these experiments suggest that winery wastewaters, after additional optimization of the process in terms of the substrate composition and the cultivation conditions, may be a suitable raw material for industrial xanthan production.

Improvement of Verdejo white wines by contact with oak chips at different winemaking stages

The effect that the addition of wood at different stages of the winemaking process has on the volatile composition and sensory characteristics of Verdejo wines has been studied. Verdejo control wine was made by the traditional winemaking process without oak chips. Oak chips (7 g/L) were added at different stages of the winemaking process: during alcoholic fermentation (OCAF) and in the young wine (OCW). Higher alcohols, ethyl acetate, hexyl acetate, isoamyl acetates and ethyl esters of straight-chain fatty acids were present at higher concentrations in wines that had contact with oak chips during alcoholic fermentation when compared to control wines. The highest concentrations of benzene compounds, oak lactones and furanic compounds were found in both wines in contact with oak chips, particularly in CW samples. Different sensorial profiles were obtained for the wines depending on the stage of the winemaking process at which the chips were added. All wines investigated in this study can provide a viable alternative to traditional Verdejo wines.

Exploitation of Simultaneous Alcoholic and Malolactic Fermentation of Incrocio Manzoni, a Traditional Italian White Wine

Malolactic fermentation (MLF) is a key feature in the production of high-quality wines. Its evolution is not always guaranteed, especially in white wine, due to certain limiting factors (low pH, sulphur dioxide, low temperature) acting against malolactic bacteria. The inoculation of grape must with bacteria is an alternative approach to the management of oenological fermentation, favouring the survival of bacteria due to the absence of ethanol or sulphur dioxide – toxic compounds made by yeasts in the first stages of winemaking. We compared the activity of two strains of Oenococcus oeni during MLF in wines made from an emerging white grape variety, native to north-eastern Italy, namely Incrocio Manzoni. Different winemaking protocols were assayed, comparing sequential or simultaneous inoculation of microbial starters. The monitoring of bacterial viability through fermentations and a comprehensive characterisation of the volatile profile of the wines were achieved by advanced analytical approaches, flow cytometry and GC-MS respectively. According to the preliminary hypothesis, the chemical composition of the grape must was characterised by high acidity, which represented a serious barrier to bacterial development. Simultaneous inoculation of the two O. oeni strains ensured a regular evolution of MLF. Some differences were highlighted, both in terms of fermentation kinetics and the aromatic profile of the wines obtained, in relation to the strain of lactic bacteria. The work provides an exhaustive overview of the opportunities and risks related to different wine fermentation approaches in order to enhance the quality of white wines made from “new” or “local” wine grapes.

Effect of Winemaking on the Composition of Red Wine as a Source of Polyphenols for Anti-Infective Biomaterials.

Biomaterials releasing bactericides have currently become tools for thwarting medical device-associated infections. The ideal anti-infective biomaterial must counteract infection while safeguarding eukaryotic cell integrity. Red wine is a widely consumed beverage to which many biological properties are ascribed, including protective effects against oral infections and related bone (osteoarthritis, osteomyelitis, periprosthetic joint infections) and cardiovascular diseases. In this study, fifteen red wine samples derived from grapes native to the Oltrepò Pavese region (Italy), obtained from the winemaking processes of “Bonarda dell’Oltrepò Pavese” red wine, were analyzed alongside three samples obtained from marc pressing. Total polyphenol and monomeric anthocyanin contents were determined and metabolite profiling was conducted by means of a chromatographic analysis. Antibacterial activity of wine samples was evaluated against Streptococcus mutans, responsible for dental caries, Streptococcus salivarius, and Streptococcus pyogenes, two oral bacterial pathogens. Results highlighted the winemaking stages in which samples exhibit the highest content of polyphenols and the greatest antibacterial activity. Considering the global need for new weapons against bacterial infections and alternatives to conventional antibiotics, as well as the favorable bioactivities of polyphenols, results point to red wine as a source of antibacterial substances for developing new anti-infective biomaterials and coatings for biomedical devices.

Optimization of Extraction of Bioactive Compounds from Different Types of Grape Pomace Produced at Wineries and Distilleries

Natural extracts obtained from grape pomace are particularly interesting, due to the substantial variety of valuable compounds present with health benefits, specifically phenolic compounds such as anthocyanins, trans-resveratrol, quercetin, and proanthocyanidins. The production of such extracts has been recognized as a profitable way to valorize grape byproducts, which are low-value and most abundant. First, the effect of the solvent on the extraction of bioactive compounds from grape pomace is studied. The selected solvents are water and ethanol, biocompatible and available in wineries and distilleries. Then, different types of grape pomace obtained along the various stages of current industrial winemaking and distillation processes are analyzed. As a result, the best stage of the winemaking and distillation processes for pomace valorization is identified, corresponding to the grape byproduct with the highest potential as source of bioactive compounds. These studies were performed with Vitis vinifera variety of Tempranillo grapes (same year, same vineyard). This work optimizes the production of natural extracts from (byproduct) grape pomace with recognized health benefits, to be used as high value nutraceuticals ingredients. The process proposed uses renewable and low-cost resources existent in wineries and distilleries. The select solvent extracting is a mixture of the biocompatible water and ethanol. The selected fermented grape pomace was chosen from different and comparable types of grape pomace obtained at current winemaking and distillation processes, to be used in extraction without any pretreatment.

Chemometric Analysis for the Detection of Biogenic Amines in Chilean Cabernet Sauvignon Wines: A Comparative Study between Organic and Nonorganic Production

In this work, the presence of biogenic amines (BAs) was correlated with the type of wine grape culture (traditional or organic) and their concentration in the different stages of winemaking (must, alcoholic fermentation [AF] and malolactic fermentation [MLF]). The formation of BA occurred mainly during MLF in which the percentages for putrescine, cadaverine, phenylethylamine, histamine, and tyramine were 100%, 70%, 13%, 61%, and 44% for the wines produced with traditional grapes and 100%, 94%, 25%, 88%, and 13% for the wines produced with organic grapes, respectively. In general, these latter wines exhibited a lower concentration of total amines. The principal component analysis and partial least-square discriminate analysis indicated that the generation of BA has a certain behavioral pattern in the wines analyzed, which is associated with the different stages of wine production and with the type of culture (traditional or organic) used in the wine grapes. Chemometrics tools can be useful as a method of characterization and classification in a global overview of the process variables involved in the development of toxic chemicals in foods, such as the production of BA in wine.

Simultaneous yeast–bacteria inoculum. A feasible solution for the management of oenological fermentation in red must with low nitrogen content

The simultaneous inoculum of yeasts and bacteria is a feasible solution for improving fermentation in wines with a harsh chemical composition, capable of inhibiting microbial activity. Considering the risk of wine spoilage due to lactic bacteria, co-inoculum is suggested in white wines with a low pH. However, climate change has also caused problems in achieving malolactic fermentation in red wines, due to the high concentration of ethanol and the low nutrient content. In this work, 5 pairs of commercial oenological starters were tested in simultaneous fermentation, using 4 red musts with a low nitrogen content, and compared with a traditional winemaking process. The simultaneous inoculum caused a slowdown in the activity of yeasts, although no problems in the accomplishment of alcoholic fermentations were observed. More reliable malolactic fermentation was performed in the co-inoculum trials, while, in traditional winemaking, some failures in the degradation of malic acid were observed. Microbiological analyses agreed with these observations. No differences were found in yeast density during alcoholic fermentation, demonstrating the absence of negative interaction between the yeast and the bacteria. However, simultaneous fermentation is not without risks; the highest increases of acetic acid were noted in the co-inoculum trials. The addition of yeast and bacteria to must with a serious lack of nutrients would appear to be a promising alternative to traditional fermentation; however, careful control of the chemical composition of must is mandatory to obtain reliable microbiological activity in the first stages of winemaking.