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1.
Influence of nitrogen status in wine alcoholic fermentation.
Gobert, A, Tourdot-Maréchal, R, Sparrow, C, Morge, C, Alexandre, H
Food microbiology. 2019;:71-85
Abstract
Nitrogen is an essential nutrient for yeast during alcoholic fermentation. Nitrogen is involved in the biosynthesis of protein, amino acids, nucleotides, and other metabolites, including volatile compounds. However, recent studies have called several mechanisms that regulate its role in biosynthesis into question. An initial focus on S. cerevisiae has highlighted that the concept of "preferred" versus "non-preferred" nitrogen sources is extremely variable and strain-dependent. Then, the direct involvement of amino acids consumed in the formation of proteins and volatile compounds has recently been reevaluated. Indeed, studies have highlighted the key role of lipids in nitrogen regulation in S. cerevisiae and their involvement in the mechanism of cell death. New winemaking strategies using non-Saccharomyces yeast strains in co- or sequential fermentation improve nitrogen management. Indeed, recent studies show that non-Saccharomyces yeasts have significant and specific needs for nitrogen. Moreover, sluggish fermentation can occur when they are associated with S. cerevisiae, necessitating nitrogen addition. In this context, we will present the consequences of nitrogen addition, discussing the sources, time of addition, transcriptome changes, and effect on volatile compound composition.
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2.
Characterisation of hybrid yeasts for the production of varietal Sauvignon blanc wine - A review.
Hart, RS, Jolly, NP, Ndimba, BK
Journal of microbiological methods. 2019;:105699
Abstract
The wine yeast Saccharomyces cerevisiae forms an integral part of wine production by converting relatively 'neutral' flavoured grape must into varietal aromatic wines. Additionally, non-Saccharomyces strains can be used with S. cerevisiae for the production of wines with more complexity. Yeast strains, to varying extents, produce and/or mediate the release of a whole range of key metabolites, which in turn contribute to enhanced aroma and flavour of the final wine, especially Sauvignon blanc. These metabolites viz. thiols are dependent on yeast-expressed enzymes during fermentation. Inoculation with an appropriate yeast will, therefore, lead to more commercial wine sales due to resultant wines with sought-after aroma and flavour. Likewise, inoculation with the incorrect yeast will have a negative effect on sales. It is also important to have quality control measures in place to ensure that the inoculated yeast strain quickly dominate, and is present throughout the fermentation process. Traditionally, the laborious contour clamped homogeneous electric field (CHEF) DNA karyotyping technique was shown to be reliable in this regard, however cutting-edge matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) biotyping is proving to be a faster alternative. As both methods have advantages and disadvantages, they should be used in complementary as opposed to competitively. Standard chemical and descriptive sensory analyses of wine also serve as evaluation and/or characterisation tools of yeast starter cultures. Additionally, metabolomic and proteomic profiling using gas chromatography (GC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of final wines was shown to be instrumental yeast evaluation tools. Therefore, this review highlights the importance and practicality of a more inclusive approach to evaluate and characterise novel yeast strains used for winemaking by deploying traditional and modern chemical and organoleptic evaluation techniques of wines in conjunction with cutting-edge omics approaches towards enhancing white wine varietal aroma.
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3.
Importance and role of lipids in wine yeast fermentation.
Tesnière, C
Applied microbiology and biotechnology. 2019;(20):8293-8300
Abstract
This review summarizes the current knowledge on the importance and role of lipids in wine yeast fermentation. Lipids play an important role in membrane structure, adaptation to stress, or as signaling molecules. They are also essential nutrients whose availability can vary depending on winemaking technology, with major effects on yeast alcoholic fermentation. Moreover, lipid supplementation can greatly stimulate the formation of yeast volatile metabolites.
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4.
Creation and validation of a reactor engineering model for multiphase red wine fermentations.
Miller, KV, Oberholster, A, Block, DE
Biotechnology and bioengineering. 2019;(4):781-792
Abstract
Red wine fermentations are performed in the presence of grape skins and seeds to ensure the extraction of color and other phenolics. The presence of these solids results in two distinct phases in the fermentor, as the solids float to the top to form a "cap." Modeling of red wine fermentation is, therefore, complex and must consider spatial heterogeneity to predict fermentation kinetics. We have developed a reactor-engineering model for red wine fermentations that includes the fundamentals of fermentation kinetics, heat transfer, diffusion, and compressible fluid flow. To develop the heat transfer component of the model, the heat transfer properties of grapes were experimentally determined as a function of fermentation progression. COMSOL was used to solve all components of the model simultaneously utilizing a finite element analysis approach. Predictions from this model were validated using prior experimental work. Model prediction and experimental data showed excellent agreement. The model was then used to predict spatial profiles of active yeast cell concentration and ethanol productivity, as well as liquid velocity profiles. Finally, the model was used to predict how these gradients would change with differences in initial bioavailable nitrogen concentration, a key parameter in predicting fermentation outcome in nitrogen-limited wine fermentations.
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5.
Loss and formation of malodorous volatile sulfhydryl compounds during wine storage.
Kreitman, GY, Elias, RJ, Jeffery, DW, Sacks, GL
Critical reviews in food science and nutrition. 2019;(11):1728-1752
Abstract
Volatile sulfur compounds (VSCs), particularly low molecular weight sulfhydryls like hydrogen sulfide (H2S) and methanethiol (MeSH), are often observed in wines with sulfurous off-aromas. Recent work has shown both H2S and MeSH can increase up to a few µM (> 40 µg/L) during anoxic storage, but the identity of the latent sources of these sulfhydryls is still disputed. This review critically evaluates the latent precursors and pathways likely to be responsible for the loss and formation of these sulfhydryls during wine storage based on the existing enology literature as well as studies from food chemistry, geochemistry, biochemistry, and synthetic chemistry. We propose that three precursor classes have sufficient concentration and metastability to serve as latent sulfhydryl precursors in wine: 1) transition metal-sulfhydryl complexes, particularly those formed following Cu(II) addition, which are released under anoxic conditions through an unknown mechanism; 2) asymmetric disulfides, polysulfanes, and (di)organopolysulfanes formed through transition-metal mediated oxidation (e.g., Cu(II)) of sulfhydryls or pesticide degradation, and released through sulfitolysis, metal-catalyzed thiol-disulfide exchange or related reactions; 3) S-alkylthioacetates, primarily formed during fermentation, and releasable hydrolytically. Some evidence also exists for S-amino acids serving as precursors. Based on these findings, we propose a "decision tree" approach to choosing appropriate strategies for managing wines with sulfurous off-aromas.
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6.
New insights on yeast and filamentous fungus adhesion in a natural co-immobilization system: proposed advances and applications in wine industry.
Ogawa, M, Bisson, LF, García-Martínez, T, Mauricio, JC, Moreno-García, J
Applied microbiology and biotechnology. 2019;(12):4723-4731
Abstract
Fungi possess extraordinary strength in attachment to biotic and abiotic surfaces. This review focuses on adhesion mechanisms of yeast and filamentous fungi and the proposed combination of the adhesive forces of both organisms in an immobilization system called yeast biocapsules, whereby Saccharomyces cerevisiae cells are attached to the hyphae of Penicillium chrysogenum. The natural adherent properties of each organism, one multicellular and another unicellular, allow yeast to be fixated securely on the filamentous fungi and complete alcoholic fermentation. Following alcoholic fermentation, the hyphae become an inert support for yeast cells while maintaining shape and integrity. Biocapsules have been used successfully in both wine and bioethanol production. Investigation of the potential genes involved in fungal-yeast fusion suggests that natural hydrophobic interactions of both organisms play a major role. Analysis of the possible mechanisms involved in fungus and yeast adhesion, future perspectives on improving yeast immobilization, and proposed applications of the biocapsules are explored.
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7.
Effects of wine on blood pressure, glucose parameters, and lipid profile in type 2 diabetes mellitus: A meta-analysis of randomized interventional trials (PRISMA Compliant).
Ye, J, Chen, X, Bao, L
Medicine. 2019;(23):e15771
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Abstract
BACKGROUND Previous studies identified conflicting results about the effects of wine intake on glucose parameters and the risk of cardiovascular diseases in type 2 diabetes mellitus (T2DM). The present study further investigated the association between wine digestion and these outcomes in T2DM patients. MATERIAL AND METHODS A search of PubMed, Embase, and Scopus databases (up to November 2018) was performed for randomized interventional trials which evaluated the effect of wine on blood pressure (BP), glucose parameters and lipid profiles in T2DM people. We used a variety of tests: fixed and random effects models, Q Cochrane test and I index, Egger and Begg tests, forest plots, and sensitivity analysis in our study. RESULTS A total of 9 randomized interventional studies were included in this meta-analysis. Overall, significant association between wine intake with diastolic BP (weighted mean difference [WMD] = 0.10; 95% confidence interval [95% CI]: -0.01 to 0.20, P = .03 I = 13%) and total cholesterol (TC) (WMD = 0.16, 95% CI: 0.02-0.31, P = .03, I = 6%), whereas no noticeable differences in glucose parameters, systolic BP, low-density lipoprotein cholesterol (LDLC), triglyceride (TG) and high-density lipoprotein cholesterol (HDLC) were identified between wine and controls groups (fasting glucose [FG],WMD = -0.00, 95% CI: -0.58 to 0.58; fasting insulin [FI], -0.22, -2.09 to 1.65; HbAc1%, -0.16, -0.40 to 0.07; systolic blood pressure, 0.12, -0.05 to 0.28; LDLC, -0.02, -0.25 to 0.21; TG, -0.34, -1.31 to 0.64; HDLC, 0.22, -0.08 to 0.53]. CONCLUSION This meta-analysis revealed that moderate wine consumption among T2DM patients could reduce the level of diastolic blood pressure and TC, but not glucose parameters and other cardiovascular risk factors.
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8.
The impacts of Schizosaccharomyces on winemaking.
Benito, S
Applied microbiology and biotechnology. 2019;(11):4291-4312
Abstract
In the past century, yeasts from the genus Saccharomyces represented the only option in fermentation industries, such as winemaking, to produce wine, beer, and other fermented products. However, other genera are currently emerging to solve challenges in modern enology. Schizosaccharomyces pombe is showing promising results in solving specific challenges in northern, cool viticulture regions with highly acidic wines by deacidifying these wines through its malic acid metabolism. In addition, this microorganism is considered beneficial in warm growing regions with challenges such as the control of wine food safety problems such as the presence of biogenic amines, ochratoxin A, or ethyl carbamate. Indeed, the genus Schizosaccharomyces positively influences other important wine quality parameters, such as color and polysaccharide content. However, the main challenge of using this genus remains the selection of proper strains that alleviate problems such as the production of high acetate concentrations. Industries other than wine production such as ginger fermentation, apple wine, Kei-apple fermentation, plum wine, sparkling wine, and bilberry fermentation industries have also started to study Schizosaccharomyces species as an alternative tool for solving specific related problems. The review discusses the influence of Schizosaccharomyces on different fermentation quality parameters and its main applications in different industries.
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A Metagenomic-Based Approach for the Characterization of Bacterial Diversity Associated with Spontaneous Malolactic Fermentations in Wine.
Berbegal, C, Borruso, L, Fragasso, M, Tufariello, M, Russo, P, Brusetti, L, Spano, G, Capozzi, V
International journal of molecular sciences. 2019;(16)
Abstract
This study reports the first application of a next generation sequencing (NGS) analysis. The analysis was designed to monitor the effect of the management of microbial resources associated with alcoholic fermentation on spontaneous malolactic consortium. Together with the analysis of 16S rRNA genes from the metagenome, we monitored the principal parameters linked to MLF (e.g., malic and lactic acid concentration, pH). We encompass seven dissimilar concrete practices to manage microorganisms associated with alcoholic fermentation: Un-inoculated must (UM), pied-de-cuve (PdC), Saccharomyces cerevisiae (SC), S. cerevisiae and Torulaspora delbrueckii co-inoculated and sequentially inoculated, as well as S. cerevisiae and Metschnikowia pulcherrima co-inoculated and sequentially inoculated. Surprisingly, each experimental modes led to different taxonomic composition of the bacterial communities of the malolactic consortia, in terms of prokaryotic phyla and genera. Our findings indicated that, uncontrolled AF (UM, PdC) led to heterogeneous consortia associated with MLF (with a relevant presence of the genera Acetobacter and Gluconobacter), when compared with controlled AF (SC) (showing a clear dominance of the genus Oenococcus). Effectively, the SC trial malic acid was completely degraded in about two weeks after the end of AF, while, on the contrary, malic acid decarboxylation remained uncomplete after 7 weeks in the case of UM and PdC. In addition, for the first time, we demonstrated that both (i) the inoculation of different non-Saccharomyces (T. delbrueckii and M. pulcherrima) and, (ii) the inoculation time of the non-Saccharomyces with respect to S. cerevisiae resources (co-inoculated and sequentially inoculated) influence the composition of the connected MLF consortia, modulating MLF performance. Finally, we demonstrated the first findings of delayed and inhibited MLF when M. pulcherrima, and T. delbrueckii were inoculated, respectively. In addition, as a further control test, we also assessed the effect of the inoculation with Oenococcus oeni and Lactobacillus plantarum at the end of alcoholic fermentation, as MLF starter cultures. Our study suggests the potential interest in the application of NGS analysis, to monitor the effect of alcoholic fermentation on the spontaneous malolactic consortium, in relation to wine.
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10.
Contribution of cross-cultural studies to understanding wine appreciation: A review.
Rodrigues, H, Parr, WV
Food research international (Ottawa, Ont.). 2019;:251-258
Abstract
People from different cultures or geographical regions vary significantly in terms of their food and beverage consumption patterns, preferences, and purchase choices. Recent decades have seen cross-cultural research in food science flourish with research programmes in fields as diverse as perception science, conceptual behaviour, health sciences, and marketing. In this review, we describe cross-cultural research that has contributed to our understanding of wine appreciation. We begin by providing a brief historical perspective, and then outline the types of studies and methodologies employed in cross-cultural wine sensory research. We then review systematically cross-cultural studies concerning intrinsic wine factors, extrinsic wine factors, cerebral representation studies and those investigating attitudes and opinions about wine, and cross-cultural research addressing emotional response to wine. Finally, we bring together the major results reported from the varying methodologies to discuss how a cross-cultural approach can help advance our understanding of wine appreciation. We also raise contemporary issues relevant to traditional ways of defining and investigating culture in light of increasing globalisation. This review is relevant for wine industry marketing strategists as well as for those interested in the science of wine tasting.