Composition of Saccharomyces cerevisiae strains in spontaneous fermentations of Pinot Noir and Chardonnay

There is a lack of knowledge about the composition of Saccharomyces cerevisiae strains in spontaneous fermentations of Pinot Noir and Chardonnay cultivars. The objectives were to determine the relative abundance of indigenous and commercial S. cerevisiae strains in spontaneous fermentations at three wineries from the two cultivars and to compare the composition of the S. cerevisiae strains between cultivars and wineries. Three fermentation vessels were sampled at three stages of fermentation for each cultivar at each winery. Isolates were identified to the strain level using seven microsatellite loci. Commercial S. cerevisiae strains were isolated at a frequency higher than that of the indigenous strains at each winery for both cultivars. The composition of S. cerevisiae strains was different for each cultivar and at each winery. Our results illustrate the clear influence of inoculated commercial active dry yeast strains on the composition of S. cerevisiae strains in spontaneous fermentations at wineries conducting both inoculated and spontaneous fermentations.     

Deacidification of red and white wines by a mutant ofSchizosaccharomyces malidevoransunder commercial winemaking conditions

A mutant ofSchizosaccharomyces malidevorans, which utilizes malic acid more rapidly than the wild-type strain and does not utilize significant amounts of glucose or fructose, was used in commercial scale deacidification of grape juice during two vintages in a New Zealand winery. Four trials were conducted in Chardonnay, Semillon and Cabernet Sauvignon juices, 1000–4500 l. In the first two trials, the juices were inoculated with the alcoholic fermentation yeast,Saccharomyces cerevisiae, 33–48 h after the mutant inoculation. In the remaining two trials, the juices were inoculated simultaneously with the mutant andS. cerevisiae. Malic acid, ranging from 3.5–10 g l⁻¹in the juices, was completely degraded within 21–73 h. TheSchiz. malidevoransmutant utilized malic acid at sulfur dioxide levels and temperatures used in red and white winemaking. The wines produced in the trials lacked obvious organoleptic defects. They were blended with untreated wines for acid balance and retailed as varietal wines.     

Influence of the farming system and vine variety on yeast communities associated with grape berries

Wine production in most countries is based on the use of commercial strains leading to the colonisation of the wineries by these strains with the consequent reduction of autochthonous biodiversity. This implies that wine styles could therefore become standardised. The vineyard could be an important source of native yeasts of oenological interest. For this reason the objective of this study was to compare two agronomic conditions with the aim of preserving yeast biodiversity in the vineyard. A three year sampling plan was designed to evaluate the influence of different agronomic parameters on the biodiversity of fermentative grape yeasts. Thus two vineyards, one organic and one conventional, with three different grape varieties (Shiraz, Grenache and Barbera) were chosen. In total, 27 samples were collected from both vineyards. Of these, 1080 colonies were isolated and a total of 9 species were identified. The strains identified as Saccharomyces cerevisiae were genotyped by microsatellite analysis obtaining nine different electrophoretic patterns. Classical ecology indexes were used to obtain the richness (S), the biodiversity (H') and the dominance (D) of the species studied. The results indicated a clear influence on grape associated yeast diversity of the phytosanitary treatment used in the vineyard. This is the first time that classical ecology indexes have been used to study the ecology of the spontaneous fermentation of grape musts and the species Candida sorbosa and Pichia toletana have been described in vineyards of the Madrid winegrowing region.     

Natural yeast flora of different varieties of grapes used for wine making in India

The natural Saccharomyces and non-Saccharomyces yeast flora present on the grape berries significantly affect wine production. Six grape varieties, Bangalore blue, Zinfandel, Cabernet, Chenin Blanc, Sauvignon Blanc and Shiraz are being used in India for wine making. The yeast diversity was studied on the basis of morphological, colony, physiological characteristics and 5.8S-ITS sequencing of rDNA of the isolates. Eleven different species belonging to seven genera were identified as: Candida azyma, Candida quercitrusa, Debaryomyces hansenii, Hanseniaspora guilliermondii, Hanseniaspora viniae, Hanseniaspora uvarum, Issatchenkia orientalis, Issatchenkia terricola, Pichia membranifaciens, Saccharomyces cerevisiae and Zygoascus steatolyticus.H. guilliermondii was the predominant species while S. cerevisiae was observed occasionally in the six vine varieties. For the first time, C. azyma was isolated from Bangalore blue and Cabernet varieties grown in different localities. This association may be attributed to the change in cropping pattern from sugarcane to viticulture in the vine growing regions and the known association of C. azyma with sugarcane phylloplane. Further analysis of the indigenous strains and the qualitative and quantitative changes in the flora during fermentation will be useful to understand wine quality and to design preservation strategies to control wine spoilage.     

Contribution by Saccharomyces cerevisiae Yeasts to Fermentation and Flavour Compounds in Wines from cv. Kalecik karasi Grape

The effect of indigenous and commercial S. cerevisiae yeasts on fermentation and flavour compounds of wines was examined in pasteurised grape juice. The flavour compounds were analysed and identified by GC‐FID and GC‐MS, respectively and in general, the amounts of these volatiles were increased by the use of both indigenous and commercial yeasts. The levels of isoamyl alcohol, isoamyl acetate, ethyl octanoate and ethyl deconoate exceeded flavour thresholds. All grape juices were fermented to dryness. Selected yeasts produced higher ethanol concentrations compared to spontaneous fermentations.     

Indigenous Saccharomyces cerevisiae strains and their influence on the quality of Cataratto, Inzolia and Grillo white wines

The present paper deals with three new strains of Saccharomyces cerevisiae, isolated in old wineries of Sicily, which were microbiologically and molecularly characterized and tested for their ability to produce white wines. Examined in terms of their growth pattern, fermentation vigour, sulphite tolerance, fermentative power, spore formation, and production of acetic acid, hydrogen sulphide and phenolic off-flavours, the strains were utilized as starters in experimental fermentations of musts obtained from the cultivars Inzolia, Grillo and Catarratto. Further, the three musts were also fermented using two commercial S. cerevisiae strains. The quality of the wines produced was confirmed by their principal oenochemical parameters, by sensory analysis and qualitative and quantitative determination of the volatile aroma constituents. All the data were statistically elaborated. Interestingly, the new selected yeasts were able to increase the pear notes (Z)-ethyl-4-decenoate, (E)-ethyl-3-decenoate, and (Z)-ethyl-3-decenoate which are fundamental for the aroma of these Sicilian wines. From our results, the new yeast strains were found to produce white wines of a quality which was not inferior to those obtainable with the best commercial strains selected in other geographical areas, but also with a distinctive aromatic profile.     

Differentiation between fermenting and spoilage yeasts in wine by total free fatty acid analysis

Differentiation between fermenting and spoilage yeasts in wine was estimated by cellular fatty acid profiles. Forty-two strains of yeasts representing 17 genera were grown on a defined liquid medium for 48 h at 25°C in a rotary shaker. After saponification of yeast cells, free fatty acid extracts were analysed by gas chromatography. Multivariate analysis was performed by Principal Components Analysis (PCA) to define clusters of fatty acids and yeasts. Strains were characterised especially by long-chain fatty acids, palmitic (C16) to linolenic (C18:3) acid under aerobic culture. Nevertheless, most of Saccharomyces cerevisiae and also Dekkera bruxellensis (former names D intermedia and Brettanomyces lumbicus) synthesized medium-chain fatty acids, octanoic (C8) acid to dodecanoic (C12) acid. With this method it was possible to differentiate fermenting grape yeasts such as S cerevisiae from spoilage yeasts on the basis of the absence of linoleic (C18:2) and linolenic (C18:3) acids. However, the method seemed unreliable for the identification of strains, more particularly those of species of S cerevisiae.     

Biodiversity of Saccharomyces cerevisiae populations in Malbec vineyards from the "Zona Alta del Río Mendoza" region in Argentina

The “Zona Alta del Río Mendoza” (ZARM) is the major Malbec grape viticulture region of Argentina. The aim of the present study was to explore Saccharomyces cerevisiae biodiversity in ZARM vineyards. Interdelta PCR and RFLP mtDNA molecular markers were applied to differentiate S. cerevisiae strains. The presence of commercial strains on ZARM vineyards was also assessed. Our results reveal a highly diverse, but genetically closely related, S. cerevisiae population (containing more than 190 molecular patterns among 590 S. cerevisiae isolates). According to the S. cerevisiae strain diversity found in vineyards, they were classified as vineyards with high and low polymorphic S. cerevisiae populations. Six vineyards showed a high polymorphic population, with more than 20 different S. cerevisiae molecular patterns. S. cerevisiae populations in these vineyards were diverse and irregularly distributed, with different strains in each vineyard site. Low polymorphic S. cerevisiae population vineyards displayed very low yeast diversity, with only 9 to 10 different S. cerevisiae strains and presence of two commercial strains widely distributed. Population diversity estimators were calculated to determine the population structure of S. cerevisiae in the ZARM vineyards. The obtained values support the hypothesis that the eight sampled subpopulations come indeed from a larger population.     

Descriptive analysis of bacterial profile,physicochemical and sensory characteristics of grape juice containing Saccharomyces cerevisiae cell wall‐coated probiotic microcapsules during storage

In this study the feasibility of incorporation of probiotic microcapsules coated with fragmented yeast cell wall in grape juice was evaluated during 60 days at 4 °C. Lactobacillus acidophilus and Bifidobacterium bifidum were encapsulated in alginate microbeads and coated with fragmented Saccharomyces cerevisiae cell wall and calcium alginate and were added into grape juice. At the end of storage, the survival of probiotics was higher than recommended minimum value (10⁷ cfu mL^?1) and the results demonstrated that applying yeast cell wall layer for L. acidophilus microcapsules significantly enhanced its survival while did not affect the survival of B. bifidum (P > 0.05). Generally, probiotic grape juice showed decrease in °Brix, pH and colour and increase in acidity and turbidity during storage and the presence of yeast wall layer had no significant effect on its properties expect colour and turbidity. Overall acceptance of grape juices containing yeast cell wall‐coated microcapsules scored the least.     

Effects of mediums on fermentation behaviour and aroma composition in pure and mixed culture of Saccharomyces cerevisiae with Torulaspora delbrueckii

The nutrient status and composition in mediums have a significant effect on yeast metabolism and phenotypic characteristics in wine fermentation. In this study, the effects of three frequently used mediums, including synthetic grape juice (SGJ), grape juice without grape pericarp and seeds (GJ) and grape must with grape pericarp and seeds (GMPS), on yeast fermentation behaviour and aroma compounds produced by pure and mixed culture of Saccharomyces cerevisiae T73 with Torulaspora delbrueckii TD20 were investigated after alcoholic fermentation. The results showed that high fermentation activities and cell population were always found in GJ medium irrespective of inoculated approach. More esters and higher alcohols were produced in GMPS medium fermented by pure S. cerevisiae, while SGJ medium had increased levels of fatty acids. Consistent with previous literatures, the mixed fermentation of T. delbrueckii and S. cerevisiae produced more acetate esters and fatty acids than the pure culture of S. cerevisiae, while this enological trait was only found in SGJ and GJ, not in GMPS. Our results highlighted that more attention should be paid to the fermentation medium when evaluating the enological and aromatic properties of selected yeasts used in industrial winemaking. In this regard, the combined use of GJ and GMPS medium might be a suitable choice.     

Flow cytometric analysis of Saccharomyces cerevisiae populations in high‐sugar Chardonnay fermentations

Fermentation of high‐sugar grape juice by five commercial strains of Saccharomyces cerevisiae was analyzed in real time both microbiologically and chemically. Viable, dead and ‘injured’ yeast were enumerated by flow cytometry. Chemical changes in the fermentations were measured by Fourier transform infrared spectroscopy. Sensory testing of wines was conducted at 3 and 6 months post bottling. Fermentation kinetics varied among the five strains of yeast, with two of the yeasts unable to completely ferment the juice. Wines differed in glycerol and volatile acidity production. Sensorial differences were detected in all wine pairs tested at 3 months, but only in one of the four wine pairs tested at 6 months. Copyright © 2006 Society of Chemical Industry     

A new simplified AFLP method for wine yeast strain typing

A simplified method of AFLP (Amplified Fragment Length Polymorphisms) is presented for typing yeast present during wine fermentations. The changes introduced allowed analysis by gel electrophoresis and considerably reduced the need for equipment. Another remarkable improvement was the use of non-labelled primers which reduces the cost of the analysis. This method was applied to reference strains from culture collection to test the reliability of the technique. A total of 180 colonies isolated from a spontaneous fermentation were typed into eleven different strains of Hanseniaspora uvarum, six of Hanseniaspora vineae, four of Candida zemplinina, and eleven of Saccharomyces cerevisiae. This method is suitable for typing yeast strains for routine grape and wine ecology analysis.     

Alternative yeasts for winemaking: Saccharomyces non-cerevisiae and its hybrids

Wine fermentation has not significantly changed since ancient times and the most traditional aspects are seen by the market as elements that uplift wine nuances and quality. In recent years, new trends have emerged from the sector in line with consumer preferences, and due to the effects of global climate change on grape ripening. In the first cases, the consumers are looking for wines with less ethanol and fruitier aromas and in the second cases the wineries want to reduce the wine alcohol levels and/or astringency. New yeast starters of alternative Saccharomyces species and their hybrids can help to solve some problems that wineries face. In this article we review several physiological and genetic aspects of S. uvarum and S. kudriavzevii and the hybrids, which are especially relevant during the winemaking process, such as their good fermentative capabilities at low temperatures, resulting in wines with lower alcohol and higher glycerol amounts.     

Influence of different yeasts on the growth of lactic acid bacteria in wine

The influence of various yeasts on the growth of lactic acid bacteria in wine was tested by inoculating Lactobacillus hilgardii, L. brevis and two strains of Leuconostoc mesenteroides into experimental wines made with twelve different yeasts of the genus Saccharomyces. Wines made from juice which had been infected with several spoilage yeasts and then fermented with a wine yeast were also tested in this way. It was found that the yeasts differed considerably in their effects on bacterial growth. In some of the experimental wines bacterial growth was delayed or failed altogether. Generally, the unfavourable influence of any yeast on bacterial growth was much reduced if the wines were left in contact with the yeast cells for some weeks after the fermentation. The significance of these results in relation to the occurrence of malo-lactic fermentation in commercial wineries is discussed.     

The Effect of Proanthocyanidins on Growth and Alcoholic Fermentation of Wine Yeast under Copper Stress

Proanthocyanidins (PAs) derived from the grape skin, as well as from grape seeds, grape stems, are an important group of polyphenols in wine. The aim of this study was to understand the effect of PAs (0.1, 1.0 g/L) on growth and alcoholic fermentation of 2 strains of Saccharomyces cerevisiae (commercial strain FREDDO and newly selected strain BH8) during copper‐stress fermentation, using a simple model fermentation system. Our results showed that both PAs and Cu²⁺ could pose significant inhibition effects on the growth of yeast cells, CO₂ release, sugar consumption, and ethanol production during the initial phase of the fermentation. Compared to PAs, Cu²⁺ performed more obvious inhibition on the yeast growth and fermentation. However, adding 1.0 g/L PAs increased in the vitality and metabolism activity of yeast cells at the mid‐exponential phase of fermentation in the mediums with no copper and 0.1 mM Cu²⁺ added, shortened the period of wine fermentation, and decreased the copper residues. It indicated that PAs could improve the ability of wine yeast to resist detrimental effects under copper‐stress fermentation condition, maintaining cells metabolic activity, and fermentation could be controlled by manipulating PAs supplementation.     

Yeast strain affects 3‐isopropyl‐2‐methoxypyrazine concentration and sensory profile in Cabernet Sauvignon wine

Background and Aims: 3‐Isopropyl‐2‐methoxypyrazine (IPMP) is both a grape‐ and insect‐derived trace compound found in wine that can contribute green characters. There has been renewed interest in examining how wine IPMP concentrations can be modulated due to recent concerns regarding ladybug taint – an off‐flavour from IPMP extracted from Harmonia axyridis (Pallas) (multicoloured Asian lady beetle). This study sought to determine the influence of commercial Saccharomyces yeast strains on IPMP concentration in Cabernet Sauvignon wines and to describe their sensory impact. Methods and Results: Rehydrated juice from Cabernet Sauvignon concentrate was spiked with 30 ng/L IPMP and fermented in triplicate by yeast strains Lalvin BM45, Lalvin EC1118, Lalvin ICV‐D21 or Lalvin ICV‐D80. IPMP concentration was determined using headspace solid‐phase micro‐extraction coupled with gas chromatography mass spectrometry (HS‐SPME‐GC‐MS), and was unchanged from juice levels in wine fermented by EC1118, Lalvin D21 and Lalvin D80 but increased by 11 ng/L (29%) in wine fermented by Lalvin BM45. Yeast strains differed in their sensory impact on wine made from IPMP‐spiked juice for five aroma and four flavour attributes. Conclusions: HS‐SPME‐GC‐MS allows for sensitive measurement of IPMP that, for the first time, has demonstrated the capacity for wine yeast to affect IPMP concentration. Yeast strains demonstrate varying ability to mask green or ladybug taint characters in wine. Significance of the Study: This information should be useful in guiding selection of yeast strains for juices of high IPMP concentration, including those that are multicoloured Asian lady beetle‐affected, under‐ripe or from varieties with high methoxypyrazine loads such as Cabernet Sauvignon.     

Study of pulsed light inactivation and growth dynamics during storage of Escherichia coli ATCC 35218, Listeria innocua ATCC 33090, Salmonella Enteritidis MA44 and Saccharomyces cerevisiae KE162 and native flora in apple,orange and strawberry juices

The response of some inoculated strains and native flora to PL treatment (Xenon lamp, 3 pulses s^?1, 10 cm distance from the lamp, 71.6 J cm^?2) in apple, orange and strawberry fresh juices with different absorbance, turbidity and particle size was investigated. Microbial growth dynamics during 12‐day storage (5 °C) of PL‐treated juices was also evaluated. PL treatments provoked 0.3–2.6 log reductions for inoculated microorganisms and 0.1–0.7 for native flora. High turbidity and particles with high UV absorbance seemed to play a major role in the PL efficiency compared to particle size. Cold storage of PL‐processed juices provoked an increase in Salmonella Enteritidis and Listeria innocua inactivation, achieving 5.0–8.0 log reductions, while no recovery of Escherichia coli and retardation for yeast growth was observed, compared to untreated samples. This study gives valuable information regarding the influence of juice variables on PL effectiveness and emphasises the beneficial effect of a postcold storage on microbial safety of PL‐treated juices.     

Yeasts Isolated from the Alcoholic Fermentation of Agave duranguensis During Mezcal Production

Mezcal is a spirit produced in some regions of México. In the state of Durango, mezcal is produced via traditional fermentation of the Agave duranguensis plant. To better understand traditional fermentation processes, it is necessary to know which yeast species are present in fermentations in different producer regions. The aim of this research was to study yeasts involved in traditional mezcal fermentation in Durango, México, and investigate the phylogeny of the native Saccharomyces cerevisiae strains involved in this process. The 5.8S-ITS genomic region was analyzed to identify strains present in the fermentation process samples in this study. To differentiate strains belonging to the genus Saccharomyces, different molecular techniques were used, including analysis of mitochondrial DNA and δ elements and sequencing of the 5.8S-ITS genomic region. Although a high diversity of microorganisms was found at the beginning of fermentation, Saccharomyces cerevisiae was the only yeast present at the end of fermentation in region I, while Torulaspora delbrueckii was found in a higher number than S. cerevisiae at the end of fermentation in the region II. Molecular techniques demonstrated that Saccharomyces cerevisiae isolated in Durango are phylogenetically independent from the strains isolated in other regions of Latin America and Europe.     

LONG-CHAIN FATTY ACID COMPOSITION AS A CRITERION FOR YEAST DISTINCTION IN THE BREWING INDUSTRY

The diversity of yeasts isolated from brewing plants and its role on beer quality makes yeast distinction a major concern in industrial microbiological control. Several approaches have been tried to develop rapid and simple methods to perform such tasks. Among these, stands the utilization of long-chain fatty acid composition of total yeast biomass. In this paper results are reported showing the potential of this technique to characterize yeast flora isolated from industrial plants. Fatty acid profiles of brewing species are clearly differentiated from those of non-Saccharomyces strains using statistical data treatment by principal component analysis (PCA). Distinction between brewing and wild strains of Saccharomyces spp. was not apparent. In comparison, fatty acid profiling showed higher discriminating ability than growth on lysine medium for non-Saccharomyces strains. For distinction of S. cerevisiae var. diastaticus from other Saccharomyces strains, growth on starch medium showed to be necessary.