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Changes in polysaccharide composition during sparkling wine making and aging.
Abstract: The evolution in polysaccharide composition and molecular weights during sparkling wine making and aging was studied for the first time in this work. Different autochthonous grape varieties from Spain (Verdejo, Viura, Malvası́a, Albarı́n, Godello, Garnacha and Prieto Picudo) were used to elaborate sparkling wines following the champenoise method. Principal component analysis showed differentiation of wines according to polysaccharide families. This differentiation was due to the process of aging on yeast lees, but not to the variety employed. The content of mannoproteins during aging was positively correlated (r = 0.792) with total polysaccharides from grapes. After six months of aging the highest content of mannoproteins and polysaccharides rich in arabinose and galactose was obtained. Also a shift to lower molecular weights was observed. The combination of these two characteristics could imply a better foam stability and thus sensory quality of sparkling wines.
Pub.: 07 Dec '13, Pinned: 10 Nov '16
The phenolic chemistry and spectrochemistry of red sweet wine-making and oak-aging.
Abstract: A natural sweet wine (NSW) was made with dried grapes from Vitis vinifera L. cv Garnacha Tintorera. A fortified sweet wine (FSW) was also obtained: the maceration-alcoholic fermentation of Garnacha Tintorera must was stopped by addition of ethanol 96% (v/v). UV/Vis spectrophotometry and HPLC/DAD-ESI/MS were applied to determine, respectively, the evolution of colour and phenolic compounds in Garnacha Tintorera based-sweet wines during aging. In sweet wines, aging decreased a(∗) (red/green), colour saturation and lightness and increased b(∗) (yellow/blue), and hue angle. Most of the phenolic compounds determined, such as anthocyanins, esters of hydroxycinnamic acids, flavan-3-ols monomers, oligomers and polymers decreased in both sweet wines during aging. On the contrary, hydroxybenzoic and hydroxycinnamic acids and vitisins increased after one year of aging. Despite that both terminal and extension subunit compositions show very small changes, mean degree of polymerisation of proanthocyanidins decline slightly as aging progressed in both sweet wines.
Pub.: 22 Jan '14, Pinned: 10 Nov '16
ELIZABETH HEATH. Wine, Sugar, and the Making of Modern France: Global Economic Crisis and the Racialization of French Citizenship, 1870-1910.
Abstract: Authors: Guy ; K. M. Article URL: http://ahr.oxfordjournals.org/cgi/content/short/121/3/1031?rss=1 Citation: Vol 121 No. 3 (2016) pp 1031 1032 Publication Date: 2016-06-06T23:35:42-07:00 Journal: American Historical Review
Pub.: 07 Jun '16, Pinned: 10 Nov '16
Effect of temperature on Chinese rice wine brewing with high concentration presteamed whole sticky rice.
Abstract: Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23 °C. The highest peak value of maltose (90 g/L) was obtained at 18 °C. Lactic acid and acetic acid both achieved maximum values at 33 °C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines.
Pub.: 29 Mar '14, Pinned: 08 Nov '16
Characteristics of traditional Chinese shanlan wine fermentation.
Abstract: Shanlan rice wine is made by a unique method by removing the saccharified liquid from wine mash constantly since it appeared during saccharification and fermentation. The objective of this study is to find the advantages of this technique of wine making by analyzing data of shanlan wine fermentation. Since the liquid was removed, the mash (rice) bed was fluffier than immersed in the saccharified liquid, under ambient condition constantly and it is favorable for starch degradation. This technique made shanlan rice wine tasted sweet and slightly acidic, lower content of alcohol and higher alcohol than in other non-distilled rice wines.
Pub.: 10 Sep '13, Pinned: 08 Nov '16
Flavor of cold-hardy grapes: impact of berry maturity and environmental conditions.
Abstract: Since the arrival on the market of high-quality cold-hardy grape varieties, northern winemaking has been developing tremendously in countries traditionally unsuited for grape and wine production. Cold-hardy grapes are mainly interspecific hybrids of Vitis vinifera with Vitis labrusca and Vitis riparia , making their chemical composition distinct from that of V. vinifera varieties traditionally used for winemaking and therefore limiting the use of current knowledge about V. vinifera varieties in the assessment of grape maturity. Consequently, to evaluate the flavor development of cold-hardy grapes in the province of Quebec, Canada, the ripening of Frontenac and Marquette berries in two vineyards located in the southwest (SW) and northeast (NE) areas of the province, starting at the beginning of veraison, was studied. Quality attributes, phenolic compounds, and aroma profiles showed significant changes during maturation. Although full maturity was reached for both Frontenac and Marquette in the SW vineyard (1380 accumulated growing degree days, based on 10 °C), the accumulation of 1035 growing degree days was not sufficient to fully ripen Frontenac and Marquette in the NE vineyard. Principal component analysis showed different ripening patterns for the two studied locations. The longer veraison in the SW vineyard resulted in higher quality attributes and higher flavor development for both Frontenac and Marquette. Under the colder conditions in the NE vineyard, metabolite accumulation was driven primarily by berry growth, and flavor development was limited. Besides growing degree days and technological parameters (total soluble solids, pH, titratable acidity), which provide significant guidelines for maturity assessment in cold climate, phenolic maturity may be followed by the accumulation of hydroxycinnamic esters and flavonoids, although the impact of these compound classes on quality remains to be determined in cold-climate wines. In both Frontenac and Marquette, aromatic maturity was best assessed using the ratio of cis-3-hexenol to trans-2-hexenal, which showed a constant decrease until maturity. Interestingly, a shift in C6 compound profile, illustrated by the progression of the sum of C6 compounds respectively produced from linoleic (C18:2; hexanal and 1-hexanol) and α-linolenic (C18:3; trans-2-hexenol and cis-3-hexenol) acids occurred during ripening, with α-linolenic acid (C18:3) degradation products decreasing in both varieties as maturation approached. At harvest, aroma profiles of both Frontenac and Marquette were dominated by C6 compounds (hexanal, trans-2-hexenal, 1-hexanol, cis-3-hexenol, and hexanoic acid), acetic acid, β-damascenone, and 2-phenylethanol, with Marquette additionally showing significant levels of monoterpenes (linalool, geraniol, and α-citral) and 1-octen-3-ol.
Pub.: 25 Oct '13, Pinned: 08 Nov '16
Influence of closure, phenolic levels and microoxygenation on Cabernet Sauvignon wine composition after 5 years' bottle storage.
Abstract: Wine aging is generally limited by the amount of oxidation, which is dependent on the amount of oxygen entering via the closure. Cabernet Sauvignon wine is well known for its high concentration of tannin, making it an ideal red wine for aging. The impact of closure type after 5 years' bottle aging has been investigated on a 2007 Cabernet Sauvignon red wine, treated with or without polyvinylpolypyrrolidone (PVPP) and micro-oxygenation (Mox). Two oxygen transfer rate (OTR) conditions (16 and 5 µg per day) into 375 mL bottles were obtained by using different synthetic stoppers.Color was evaluated by UV-visible spectrophotometry, carbonyls by 2,4-dinitrophenylhydrazine derivatization, phenolics by high-performance liquid chromatography and sulfur dioxide by the aspiration method. Closure type strongly influenced color parameters involving SO2 bleaching and some phenolics, particularly quercetin, were affected, but there was little effect on carbonyls other than acetaldehyde. PVPP treatment afforded wines with the lowest levels of phenolics and color density, but highest acetaldehyde. Few effects of Mox could be detected.Closure OTR strongly affects sulfur dioxide levels - the primary antioxidant in wine - in aged wine, but phenolic levels substantially alter the secondary reactions of oxidative aging.
Pub.: 17 Apr '14, Pinned: 08 Nov '16
Wine and headache.
Abstract: The notion of migraine attacks triggered by food and beverages has been posited for centuries. Red wine in particular has been acknowledged as a migraine trigger since antiquity when Celsus (25 B.C.-50 A.D.) described head pain after drinking wine. Since then, references to the relationship between alcohol ingestion and headache attacks are numerous. The most common initiator of these attacks among alcoholic beverages is clearly wine. The aim of this review is to present and discuss the available literature on wine and headache.A Medline search with the terms headache, migraine, and wine was performed. Data available on books and written material about wine and medicine as well as abstracts on alcohol, wine, and headache available in the proceedings of major headache meetings in the last 30 years were reviewed. In addition, available technical literature and websites about wine, grapes, and wine making were also evaluated.Full papers specifically on headache and wine are scarce. General literature related to medicine and wine is available, but scientific rigor is typically lacking. The few studies on wine and headache were mostly presented as abstracts despite the common knowledge and patients' complaints about wine ingestion and headache attacks. These studies suggest that red wine, but not white and sparkling wines, do trigger headache and migraine attacks independently of dosage in less than 30% of the subjects.Wine, and specifically red wine, is a migraine trigger. Non-migraineurs may have headache attacks with wine ingestion as well. The reasons for that triggering potential are uncertain, but the presence of phenolic flavonoid radicals and the potential for interfering with the central serotonin metabolism are probably the underlying mechanisms of the relationship between wine and headache. Further controlled studies are necessary to enlighten this traditional belief.
Pub.: 08 May '14, Pinned: 08 Nov '16
Wine aroma compounds in grapes: a critical review.
Abstract: Volatile organic compounds are vital to wine quality, determining their aroma and varietal characteristics. Which are present, and in what quantity, depends on the cultivar, the situation and soil of the vineyard, weather, cultivation methods, and wine-making practices. Here, we review the literature on the development of wine aroma compounds in grapes, and how it is affected by the above-named factors. Increasing understanding of these processes at the molecular level will aid vine growers in the optimal selection of harvest dates and other decisions favoring the consistent production of balanced, flavorful berries.
Pub.: 11 Jun '14, Pinned: 08 Nov '16
New insights into the capacity of commercial wine yeasts to grow on sparkling wine media. Factor screening for improving wine yeast selection.
Abstract: During the production of sparkling wine, wine yeasts are subjected to many stress factors apart from ethanol, which lead to the need to achieve their acclimation in line with various industrial protocols. In the present work, 44 commercial wine Saccharomyces cerevisiae strains and one laboratory strain (BY4742) were firstly subjected to the influence of increasing concentrations of ethanol to cluster the yeasts using discriminant function analysis. Afterwards, non-inhibitory concentration (NIC) and minimum inhibitory concentration (MIC) were estimated, revealing some differences between 24 of these strains. Meanwhile, this study confirms the negative synergistic effect of low pH with ethanol on the maximum specific growth rate (μmax) and lag phase time. Moreover, a negative effect of increasing levels of glycerol in the growth medium was observed. Interestingly enough, an interactive positive effect was found between cysteine and medium-chain fatty acids (MCFA). While cysteine did not have a really significant effect in comparison to the control, it was able to restore the damage caused by MCFA, making the growth rate of cells recover and even reducing the formation of reactive oxygen species. Adequate culture aeration is also crucial for the composition of the cell fatty acid. The final results showed that few differences were observed between NIC and MIC estimations with respect to cells pre-cultured in the presence or absence of oxygen.
Pub.: 21 Mar '15, Pinned: 08 Nov '16
Wine microbiome, a dynamic world of microbial interactions.
Abstract: Most fermented products are generated by a mixture of microbes. These microbial consortia possess various biological activities responsible for the nutritional, hygienic, and aromatic qualities of the product. Wine is no exception. Substantial yeast and bacterial biodiversity is observed on grapes, and in both must and wine. The diverse microorganisms present interact throughout the winemaking process. The interactions modulate the hygienic and sensorial properties of the wine. Many studies have been conducted to elucidate the nature of these interactions, with the aim of establishing better control of the two fermentations occurring during wine processing. However, wine is a very complex medium making such studies difficult. In this review, we present the current state of research on microbial interactions in wines. We consider the different kinds of interactions between different microorganisms together with the consequences of these interactions. We underline the major challenges to obtaining a better understanding of how microbes interact. Finally, strategies and methodologies that may help unravel microbe interactions in wine are suggested.
Pub.: 13 Jun '15, Pinned: 08 Nov '16
Yeast diversity on grapes in two German wine growing regions.
Abstract: The yeast diversity on wine grapes in Germany, one of the most northern wine growing regions of the world, was investigated by means of a culture dependent approach. All yeast isolates were identified by sequence analysis of the D1/D2 domain of the 26S rDNA and the ITS region. Besides Hanseniaspora uvarum and Metschnikowia pulcherrima, which are well known to be abundant on grapes, Metschnikowia viticola, Rhodosporidium babjevae, and Curvibasidium pallidicorallinum, as well as two potentially new species related to Sporidiobolus pararoseus and Filobasidium floriforme, turned out to be typical members of the grape yeast community. We found M. viticola in about half of the grape samples in high abundance. Our data strongly suggest that M. viticola is one of the most important fermenting yeast species on grapes in the temperate climate of Germany. The frequent occurrence of Cu. pallidicorallinum and strains related to F. floriforme is a new finding. The current investigation provides information on the distribution of recently described yeast species, some of which are known from a very few strains up to now. Interestingly yeasts known for their role in the wine making process, such as Saccharomyces cerevisiae, Saccharomyces bayanus ssp. uvarum, Torulaspora delbrueckii, and Zygosaccharomyces bailii, were not found in the grape samples.
Pub.: 21 Aug '15, Pinned: 08 Nov '16
Effects of Fermentation Temperature on Key Aroma Compounds and Sensory Properties of Apple Wine.
Abstract: Fermentation temperature strongly affects yeast metabolism during apple wine making and thus aromatic and quality profiles. In this study, the temperature effect during apple wine making on both the key aroma compounds and sensory properties of apple wine were investigated. The concentration of nine key aroma compounds (ethyl acetate, isobutyl acetate, isopentylacetate, ethyl caprylate, ethyl 4-hydroxybutanoate, isobutylalcohol, isopentylalcohol, 3-methylthio-1-propanol, and benzeneethanol) in apple wine significantly increased with the increase of fermentation temperature from 17 to 20 °C, and then eight out of the nine key aroma compounds with an exception of ethyl 4-hydroxybutanoate, decreased when the temperature goes up 20 to 26 °C. Sensory analysis showed that the apple wine fermented at 20 °C had the highest acceptance for consumers. Fermentation at the temperature of 20 °C was therefore considered to be the most suitable condition using the selected yeast strain (Saccharomyces cerevisiae AP05) for apple wine making. Changes in the fermentation temperature can considerably affect the production of key aroma compounds and sensory profiles of apple wine. These results could help apple wine producers make better quality production for consumers at the optimal fermentation temperature.
Pub.: 29 Oct '15, Pinned: 08 Nov '16
Evolutions of volatile sulfur compounds of Cabernet Sauvignon wines during aging in different oak barrels.
Abstract: The evolution of volatile sulfur compounds (VSCs) in Cabernet Sauvignon wines from seven regions of China during maturation in oak barrels was investigated. The barrels were made of different wood grains (fine and medium) and toasting levels (light and medium). Twelve VSCs were quantified by GC/FPD, with dimethyl sulfide (DMS) and methionol exceeding their sensory thresholds. Most VSCs tended to decline during the aging, while DMS was found to increase. After one year aging, the levels of DMS, 2-methyltetrahy-drothiophen-3-one and sulfur-containing esters were lower in the wines aged in oak barrels than in stainless steel tanks. The wood grain and toasting level of oak barrels significantly influenced the concentration of S-methyl thioacetate and 2-methyltetrahy-drothiophen-3-one. This study reported the evolution of VSCs in wines during oak barrel aging for the first time and evaluated the influence of barrel types, which would provide wine-makers with references in making proposals about wine aging.
Pub.: 28 Feb '16, Pinned: 08 Nov '16
West versus East: Measuring the development of Chinese wine preferences
Abstract: Sensory science and marketing are two disciplines, which measure and predict consumer preferences toward product features. However, whilst sensory science mainly deals with intrinsic product characteristics (i.e. sensory attributes), marketing focuses mainly on extrinsic product characteristics, such as packaging, price, and communication. The purpose of the paper is to highlight some of the methods used in marketing in combination with sensory science techniques to understand changing consumer preferences. The paper focuses on charting the development of preferences and consumption situations for grape-based wine in China. Five different studies using different analytical techniques are summarised. The methodologies include Check-All-That-Apply (CATA), Best–Worst Scaling (BWS), Discrete Choice Experiments (DCEs), using blind tasting as the dependent variable for wine training, and latent growth modelling (LGM). In many cases novel uses of the techniques are illustrated, such as using CATA for measuring the positioning of countries of origin in Chinese wine consumer’s minds. The results show that the combination of marketing techniques with sensory evaluation can improve decision-making and provide valuable information to producers and marketers.
Pub.: 15 Feb '16, Pinned: 08 Nov '16
Fungus resistant grape varieties as a suitable alternative for organic wine production: Benefits, limits, and challenges
Abstract: Areas dedicated to organic wine production have significantly increased over the last few years. The vast majority of organic wine is made from Vitis vinifera varieties that are highly susceptible to fungal diseases and pests, making organic management difficult for growers. Depending on the growing area, 20–70% of organic growers declare issues with fungal diseases in Europe. Recently, fungus-resistant grape (FRG) varieties have been recommended as the most suitable choice in organic viticulture, especially in areas where disease pressure necessitates high rates of fungicides. FRG varieties could contribute to improved disease management in organic as well as conventional viticulture, reduce production costs and decrease copper accumulation in soils. Recently, many FRG varieties presenting advantageous agronomic attributes and enological characteristics have been developed in North America and Europe for conventional and sustainable farming. In this review, we present an overview of the benefits and limits associated with FRG varieties in addition to the current knowledge regarding berry and wine composition, canopy management, and winemaking challenges and practices.
Pub.: 06 Apr '16, Pinned: 08 Nov '16
The family variable in the French and Italian wine sector
Abstract: EuroMed Journal of Business, Volume 11, Issue 1, May 2016. Purpose The objective of the research was to highlight the differences in terms of economic and financial performance, between family firms (FFs) and non-family firms (NFFs) in the wine sector in Italy and France, where this sector is one of the most representative national economic activities. Design/methodology/approach This study is based on a sample of Italian and France companies operating in the wine sector. The sample, including medium and large firms, includes 288 FFs and 302 NFFs, for a total of 590 firms. Amadeus database represents the data source. According to Astrachan and Kolenko (1994), a firm is classified as a family firm if family had to own over 50% of the business in a private company or more than 10% of a public company. Findings This study confirms that the family variable is relevant to achieve good economic and financial performance, and endow firms with different features. In terms of economic performance, FFs both in Italy and France outperform in terms of ROE and ROA, though only Italian NFFs outperform in EBIT. In terms of financial performance, both in Italy and France NFFs outperform FFs in current ratio and liquidity ratio, while FFs outperform in solvency ratio. Research limitations/implications Limitations of the study concern the method adopted, as it could be integrated with some econometrical models. The implications of our paper are relevant for families and regulatory bodies because it helps them to better understand the effects of governance on economic and financial performance. Moreover, the findings of the study can influence the decision-making process of investors in order to identify the long-term outperformers listed on a stock exchange. Originality/value This study contributes to the literature on family businesses phenomenon on wine sector, which represents one of the most representative of the economy of several countries and in which family businesses are widespread.
Pub.: 11 Mar '16, Pinned: 08 Nov '16
The Economics of Wine, Weather, and Climate Change
Abstract: In this article, we provide an overview of the extensive literature on the impact of weather and climate on grapes and wine, with the goal of identifying how climate change is likely to affect their production. We first discuss the physical impact of weather on vine phenology (i.e., the timing of biological events such as bud break or flowering), berry composition, and yields. Then we examine the economic literature that measures the effects of temperature on wine quality, prices, costs, and profits and, based on this review, infer how climate change will affect these variables. We also describe what has been learned thus far about possible adaptation strategies for grape growers that would allow them to mitigate the economic effects of climate change. We conclude that climate change is likely to produce both winners and losers, with the winners being those located closer to the North and South Poles. There are also likely to be some substantial short-run costs as growers adapt to climate change. Nevertheless, wine making has survived through thousands of years of recorded history, a history that has included significant climate changes. (JEL: Q13, Q18, Q54)
Pub.: 02 Feb '16, Pinned: 08 Nov '16
Making wine and making successful wineries: resource development in new ventures
Abstract: International Journal of Organizational Analysis, Volume 24, Issue 1, March 2016. Purpose Most research on new organizations drawing on resource-based theory examines firms in discrete development stages with resources that already exist. This paper articulates a broader view of changing resource requirements over the life of new organizations. We propose four phases of resources development, arguing that new resources and capabilities must develop as new strategic challenges emerge. We identify salient resources in these phases and find that internal resource development is context-dependent, interacting with the external stage of industry development. Design/methodology/approach After developing our theoretical model we use an exploratory qualitative study involving extensive case studies of new ventures in the wine industry. Key personnel at a sample of firms were interviewed supplemented with secondary data from published reports. Findings We find that a linear stage development model for new organizational ventures is inappropriate. The various combinations of early/later new ventures in a formative/developed industry suggest that some may proceed rapidly in a linear fashion through phases of development, while others may find progress slow, difficult, stalled, or occasionally regressive. a combination of resources developed simultaneously in a non-linear pattern appears to be critical to the success of new ventures. In other words, combinations must evolve as the strategic challenges evolve thus bringing an important contextual view to the examination of dynamic resource development efforts for new organizations. Attempts to focus in a piecemeal fashion on individual aspects of resource development, without accounting for resource interactions at a systemic level or the nature of the strategic demands, is likely to leave researchers and practitioners with incomplete insights. Originality/value Existing studies have failed to grasp the dynamic and interactive process of resource development as organizations evolve in a new industry setting. Our model provides a heuristic device for conceptualizing these changes.
Pub.: 29 Jan '16, Pinned: 08 Nov '16
Influence of grape maturity on complex carbohydrate composition of red sparkling wines.
Abstract: This paper studied how grape maturity affected complex carbohydrate composition during red sparkling wine making and wine aging. Grape ripening stage (premature and mature grapes) showed a significant impact on the content, composition and evolution of polysaccharides and oligosaccharides of sparkling wines. Polysaccharides rich in arabinose and galactose, mannoproteins, rhamnogalacturonans II and oligosaccharides in base wines increased with maturity. For both maturity stages, polysaccharides rich in arabinose and galactose, and glucuronic acid glycosyl residue of the oligosaccharides were the major carbohydrates detected in all vinification stages. Total glycosyl content of oligosaccharides decreased during the whole period of aging on yeast lees. The reduction of polysaccharides rich in arabinose and galactose and rhamnogalacturonans type II during the aging was more pronounced in mature samples. To our knowledge, this is the first time to report the polysaccharide and oligosaccharide composition in red sparkling wines.
Pub.: 27 May '16, Pinned: 08 Nov '16
Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model ☆
Abstract: Chinese rice wine making is a typical simultaneous saccharification and fermentation (SSF) process. During the fermentation process, temperature is one of the key parameters which decide the quality of Chinese rice wine. To optimize the SSF process for Chinese rice wine brewing, the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model. The kinetic parameters as a function of temperature were evaluated using the software Origin8.0. Combing these functions with the mathematical model, an appropriate form of the model equations for the SSF considering the effects of temperature were developed. The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model. The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm. The optimum temperature profile began at a low temperature of 26 °C up to 30 h. The operating temperature increased rapidly to 31.9 °C, and then decreased slowly to 18 °C at 65 h. Thereafter, the temperature was maintained at 18 °C until the end of fermentation. A maximum ethanol production of 89.3 g/L was attained. Conceivably, our model would facilitate the improvement of Chinese rice wine production at the industrial scale.
Pub.: 31 May '16, Pinned: 08 Nov '16
Using mixed inocula of Saccharomyces cerevisiae killer strains to improve the quality of traditional sparkling-wine
Abstract: The quality of traditional sparkling-wine depends on the aging process in the presence of dead yeast cells. These cells undergo a slow autolysis process thereby releasing some compounds, mostly colloidal polymers such as polysaccharides and mannoproteins, which influence the wine's foam properties and mouthfeel. Saccharomyces cerevisiae killer yeasts were tested to increase cell death and autolysis during mixed-yeast-inoculated second fermentation and aging. These yeasts killed sensitive strains in killer plate assays done under conditions of low pH and temperature similar to those used in sparkling-wine making, although some strains showed a different killer behaviour during the second fermentation. The fast killer effect improved the foam quality and mouthfeel of the mixed-inoculated wines, while the slow killer effect gave small improvements over single-inoculated wines. The effect was faster under high-pressure than under low-pressure conditions. Wine quality improvement did not correlate with the polysaccharide, protein, mannan, or aromatic compound concentrations, suggesting that the mouthfeel and foaming quality of sparkling wine are very complex properties influenced by other wine compounds and their interactions, as well as probably by the specific chemical composition of a given wine.
Pub.: 08 Jun '16, Pinned: 08 Nov '16
A taste of science: Making the subjective objective in the California wine world
Abstract: This article is about the relationship between the categories of the subjective and the objective in the late 20th-century California wine world, about attempts to transform ‘soft’ subjective judgments into ‘hard’ objective descriptions and evaluations, and about the role of both sensory science and chemistry in such attempts. It focuses on research done at the University of California, Davis, from about the 1950s to the 1980s by the enologist Maynard Amerine, his co-workers, and successors. It suggests ways in which these materials might prompt attention to the role of subjective judgment and the marketplace in other forms of late modern science.
Pub.: 21 Jun '16, Pinned: 08 Nov '16
Research Progress on the Brewing Techniques of New-type Rice Wine
Abstract: As a traditional alcoholic beverage, Chinese rice wine (CRW) with high nutritional value and unique flavor has been popular in China for thousands of years. Although traditional production methods had been used without change for centuries, numerous technological innovations in the last decades have greatly impacted on the CRW industry. However, reviews related to the technology research progress in this field are relatively few. This article aimed at providing a brief summary of the recent developments in the new brewing technologies for making CRW. Based on the comparison between the conventional methods and the innovative technologies of CRW brewing, three principal aspects were summarized and sorted, including the innovation of raw material pretreatment, the optimization of fermentation and the reform of sterilization technology. Furthermore, by comparing the advantages and disadvantages of these methods, various issues are addressed related to the prospect of the CRW industry.
Pub.: 06 Aug '16, Pinned: 08 Nov '16