South African Journal of Enology & Viticulture最新文献

{"title":"Yeast and its Importance to Wine Aroma - A Review","authors":"M. Lambrechts, I. S. Pretorius","doi":"10.21548/21-1-3560","DOIUrl":"https://doi.org/10.21548/21-1-3560","url":null,"abstract":"The most mysterious aspect of wine is the endless variety of flavours that stem from a complex, completely non-linear system of interactions among many hundreds of compounds. In its widest sense, wine flavour refers to the overall impression of both aroma and taste components. Aroma is usually associated with odorous, volatile compounds; the bouquet of wine refers to the more complex flavour compounds which evolve as a result of fermentation, elevage and ageing. With the exception of terpenes in the aromatic grape varieties and alkoxypyrazines in the herbaceous cultivars, perceived flavour is the result of absolute amounts and specific ratios of many of these interactive compounds, rather than being attributable to a single \"impact\" compound. Without underestimating the complexity of these interactive effects or negating the definitive role played by the accumulated secondary grape metabolites in the varietal character of wine, this review will focus mainly on the contribution of yeast fermentation to the sensorial quality of the final product. Yeast and fermentation conditions are claimed to be the most important factors influencing the flavours in wine. Both spontaneous and inoculated wine fermentations are affected by the diversity of yeasts associated with the vineyard and winery. During the primary alcoholic fermentation of sugar, the wine yeast, Saccharomyces cerevisiae, together with other indigenous non-Saccharomyces species, produce ethanol, carbon dioxide and a number of by-products. Of these yeast-derived metabolites, the alcohols, acetates and C4-C8 1tfatty acid ethyl esters are found in the highest concentration in wine. While the volatile metabolites contribute to the fermentation bouquet ubiquitous to all young wines, the production levels of these by-products are variable and yeast strain specific. Therefore, this article also highlights the importance of untapping the hidden wealth of indigenous yeast species present on grapes, and the selection and genetic development of yeast starter culture strains with improved flavour profiles. In the future, some winemakers may prefer to use mixtures of indigenous yeast species and tailored S. cerevisiae strains as starter cultures to reflect the biodiversity and stylistic distinctiveness of a given region. This will help winemakers to fullfil the consumer's demand for individual wines with intact local character and to ensure the survival of wine's most enthralling aspect - its endless variety.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90320277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical and Sensorial Characterization of Tropical Syrah Wines Produced at Different Altitudes in Northeast of the Brazil","authors":"J. B. D. Oliveira, Ricardo Egipto, O. Laureano, MT Romo Castro, G. Pereira, J. Ricardo-da-Silva","doi":"10.21548/40-2-3101","DOIUrl":"https://doi.org/10.21548/40-2-3101","url":null,"abstract":"Over the years, viticulture has expanded to new regions outside the temperate zones, such as Northeast Brazil, India, Thailand, Myanmar, Vietnam, Bangladesh and Venezuela, characterized by the production of tropical wines. It is important for the productive sector to comprehend the effects of grapevine interaction with the characteristics of each new region on wines composition. In this study, the composition of wines of Syrah from two regions with different altitudes in Northeast Brazil were analyzed by different methodologies to characterize chemical compounds as sugar, acids, minerals, phenolics (anthocyanins, flavonols, stilbenes and condensed tannins) and the sensory profile. The wines of the Bahia region (1100 m of altitude) obtained high concentrations for chemical parameters related to color, monomeric anthocyanins, stilbenes and monomeric and oligomeric tannins. Wines of the low altitude region, Pernambuco (350 m of altitude) were characterized by higher concentrations of flavonols (kaempferol, isorhamnetin, quercetin and rutin) and polymerized tannins. The chemical composition of wines from the two studied regions was influenced by altitude. A trend towards higher concentrations in most for phenolic compounds analyzed was observed in wines from the higher altitude region during the two years of study. Regarding the sensory profile, fruity, floral, herbaceous and empyreumatic attributes aromatic obtained highest scores in wines of the 350 m altitude region, the other attributes were dependent on the year of harvest.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90841148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Anatomy and Morphology of the Leaves of Grenache Noir and Syrah Grapevine Cultivars","authors":"P. Gago, G. Conéjéro, María-Carmen Martínez, P. This, J. Verdeil","doi":"10.21548/40-2-3031","DOIUrl":"https://doi.org/10.21548/40-2-3031","url":null,"abstract":"Grenache Noir and Syrah are two of the grapevine (Vitis vinifera L.) cultivars used to a great extent worldwide.  They have very different leaf morphologies from an ampelographic (botanical) point of view. This might also be related to differences in the anatomy and micro-morphology of their leaves. The goal of the present work was to compare these cultivars’ leaf anatomy and morphology. Adult leaves from both cultivars were characterised using a range of microscopy techniques. Grenache Noir had a significantly smaller leaf surface area, but a significantly thicker leaf blade, than Syrah. It also had significantly larger stomata and a larger stomatal index than Syrah. The distribution of mesophyll tissues was similar in both cultivars, but the upper epidermis was significantly thicker in Grenache Noir, and the palisade parenchyma cells were longer in Syrah. The mesophyll tissues of both cultivars contained abundant idioblasts carrying crystals of calcium oxalate and mucilage. This work reveals quantitative and qualitative differences in the anatomy and morphology of mature Grenache Noir and Syrah leaves. Further work is needed to determine how these anatomical and morphological differences may be connected with different responses at the functional level.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83620193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enzymes in Winemaking: Harnessing Natural Catalysts for Efficient Biotransf ormations - A Review","authors":"P. V. Rensberg, I. S. Pretorius","doi":"10.21548/21-1-3558","DOIUrl":"https://doi.org/10.21548/21-1-3558","url":null,"abstract":"Enzymes play a definitive role in the ancient and complex process of winemaking. From a scientific and technical point of view, wine can be seen as the product of enzymatic transformation of grape juice. From the pre-fermentation stage, through fermentation, post-fermentation and aging, enzymes are the major driving forces catalysing various biotransformation reactions. These biocatalysts originate not only from the grape itself but also from yeasts and other microbes (fungi and bacteria) associated with vineyards and wine cellars. Through better understanding of these enzymatic activities, winemakers have come to learn how to control the unwanted enzymes while optimising the desired activities. Today, winemakers reinforce and extend the action of these endogenous enzymes by the judicious application of an ever-increasing spectrum of commercial enzyme preparations. These enzyme preparations are applied to winemaking with the aims of improving the clarification and processing of wine, releasing varietal aromas from precursor compounds, reducing ethyl carbamate formation and lowering alcohol levels. This review article summarises the most important enzymes applied to winemaking, the nature and structure of their substrates, and the reactions catalysed by these enzymes. This paper also reviews the limitations of the endogenous enzymes derived from grapes and microbes present in must and wine, along with the effects of commercial enzyme preparations on process technology and the quality of the final product. Prospects of developing wine yeast strains expressing tailored enzymes are also highlighted.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87025852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Yeast Stress Response and Fermentation Efficiency: How to Survive the Making of Wine - A Review","authors":"F. Bauer, I. S. Pretorius","doi":"10.21548/21-1-3557","DOIUrl":"https://doi.org/10.21548/21-1-3557","url":null,"abstract":"Fermentation predictability and wine quality are directly dependent on wine yeast attributes that assist in the rapid establishment of numerical dominance in the early phase of wine fermentation, and that determine the ability to conduct an even and efficient fermentation to obtain a desirable alcohol degree. It is therefore not surprising that the primary selection criteria applied to most wine yeast strain development programmes relate to the overall objective of achieving an efficient conversion of grape sugar to alcohol and carbon dioxide, at a controlled rate and without the development of off-flavours. Numerous factors influence the fermentation performance of wine yeast.  Following a successful inoculation of grape must with an appropriate starter culture strain, the ability of a wine yeast to adapt to and cope with the hostile environment and stress conditions prevailing in grape juice fermentation are of vital importance to fermentation performance. There is a direct correlation between fermentation efficiency and stress resistance, which refers to the ability of a yeast strain to adapt efficiently to a changing environment and unfavourable growth conditions. Successful yeast cellular adaptation to changes in extracellular parameters during wine fermentation requires the timely perception (sensing) of chemical or physical environmental parameters, followed by accurate transmission of the information to the relevant compartments of the cell.  Chemical parameters perceived during wine fermentation include the availability/concentration of certain nutrients (e.g., fermentable sugars, assimilable nitrogen, oxygen, vitamins, minerals, ergosterol and unsaturated fatty acids) and the presence of inhibitory substances (e.g., ethanol, acetic acid, fatty acids, sulfite, phenolic phytoalexins, mycotoxins, bacterial toxins and agrochemical residues). Signals of a physical nature include temperature, pH, agitation and osmotic pressure. The sensing of these environmental signals is carried out by specific receptor proteins, most of them situated on the cellular surface. Once perceived, the information is transmitted by a network of dedicated, interconnected signal transduction pathways to the relevant cellular compartments which implement the adaptive response, a process referred to as \"stress response\". Intensive research has focused on elucidating the molecular mechanisms involved in stress responses, which are evolutionarily well conserved. Besides furthering our understanding of the fundamental strategies for adaptation to hostile, industrial environments, and the biological resilience of Saccharomyces cerevisiae, the data are of key importance to the future improvement of wine yeast strains. This review describes the different types of stress experienced by wine yeast cells during their life cycles, summarises our current knowledge of some of the most important molecular processes required for the survival of the yeast cell, and highlights the po","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84064938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial Spoilage and Preservation of Wine: Using Weapons from Nature's Own Arsenal -A Review","authors":"M. Toit, I. S. Pretorius","doi":"10.21548/21-1-3559","DOIUrl":"https://doi.org/10.21548/21-1-3559","url":null,"abstract":"The winemaking process includes multiple stages at which microbial spoilage can occur, altering the quality and hygienic status of the wine and rendering it unacceptable. The major spoilage organisms include species and strains of the yeast genera Brettanomyces, Candida, Hanseniaspora, Pichia, Zygosaccharomyces etc., the lactic acid bacterial genera Lactobacillus, Leuconostoc, Pediococcus, etc. and the acetic acid bacterial genera Acetobacter and Gluconobacter. The faults caused include bitterness and off.flavours (mousiness, ester taint, phenolic, vinegary, buttery, geranium tone), and cosmetic problems such as turbidity, viscosity, sediment and film formation. These spoilage organisms can also affect the wholesomeness of wine by producing biogenic amines and precursors of ethyl carbamate. The judicious use of chemical preservatives such as sulphur dioxide (S02) during the winemaking process decreases the risk of microbial spoilage, but strains vary considerably in their S02 sensitivity. There is, moreover, mounting consumer bias against chemical preservatives, and this review focuses on the possible use of biopreservatives in complying with the consumers' demand for \"clean and green\" products.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77825481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Improvement of Grapevine: Tailoring Grape Varieties for The Third Millennium - A Review","authors":"M. Vivier, I. S. Pretorius","doi":"10.21548/21-1-3556","DOIUrl":"https://doi.org/10.21548/21-1-3556","url":null,"abstract":"The remarkable propagative aptitute of grapevine is one of the key factors contributing to its success as a cultivated species and to the spread of the domesticated grapevine, establishing it as one of the most important fruit species worldwide. Today there are some 8 million hectares of vineyards across the world. It is therefore titting that the successful implementation of the powerful technology of gene manipulation in grapevine is to a large extent reliant on this regenerative ability. Currently, several varieties of grapevines have been successfully genetically transformed, largely by employing somatic embryogenesis to generate highly regenerative target material. Especially attractive in the wine industry is the possibility of improving grapevine varieties by the addition of genes that confer useful traits, such as resistances against biotic and abiotic factors and manipulation of certain metabolic functions. In principle, gene transfer technology allows for the directed manipulation of a specific trait without altering the characteristic nature of the cultivar, permitting the improvement of the traditional cultivars while maintaining their established varietal characteristics. For the most part, targeted traits currently include disease resistance and improved berry quality. The promise of this technology is threatened by worldwide resistance to genetically modified organisms, and in the wine industry by complications surrounding the property rights and naming of transgenic vines. If it is not possible to maintain the varietal name when a transgenic vine has the same properties as the original well known variety, the significant advantages of gene technology over traditional breeding programmes are to a large extent lost. If these and other complications can be overcome, the integration of this powerful technology with traditional breeding programmes, and with other initiatives such as the study of the grapevine genome, will ensure a new era in the cultivation of this ancient species.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83497028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free Radical-scavenging Activity and Anthocyanin Profiles of Cabernet Sauvignon and Merlot Wines from Four Wine Grapegrowing Regions in China","authors":"B. Jiang, Zhen-wen Zhang","doi":"10.21548/40-1-2932","DOIUrl":"https://doi.org/10.21548/40-1-2932","url":null,"abstract":"The present study focused on the free radical-scavenging activity and anthocyanin profiles of Cabernet Sauvignon and Merlot wines produced from four different regions in China. The anthocyanin profiles in all wine samples were analysed by HPLC-MS/MS, while the free radical-scavenging activity was estimated by the DPPH assay. The results show that the contents of phenolic subclasses and the levels of antioxidant activity in all wine samples varied greatly among cultivars and environmental factors of vine growth, and these values were the most prominent in Yuquanling regional wines. As the main components in anthocyanins, the percentages of malvidin-3-O-glucoside and its derivatives showed differences within grape cultivars in the different regional wines; these monomeric anthocyanins (not present simultaneously in the four regional wines studied within grape cultivars) had concentrations below 10 mg Mv/L. The significant correlation was obtained between DPPH-scavenging ability and the total phenolic, flavonoid and anthocyanin content. It can be concluded that this information could be used as a biochemical marker for the authenticity of the single-cultivar red wines that were produced from the four regions above.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79374262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Abiotic Factors on Phenolic Compounds in the Grape Berry – A Review","authors":"E. H. Blancquaert, Anita Oberholster, J. Ricardo-da-Silva, A. Deloire","doi":"10.21548/40-1-3060","DOIUrl":"https://doi.org/10.21548/40-1-3060","url":null,"abstract":"Grape berry phenolic compounds are widely described in literature. Phenolics can be divided into two main groups: flavonoids and non-flavonoids, of which the flavonoids are the most important. The two bestknown groups of flavonoids are the anthocyanins and condensed tannins (also called proanthocyanidins).  Anthocyanins are responsible for the red colour in grapes. The condensed tannins (proanthocyanidins) are responsible for some major wine sensorial properties (astringency, browning, and turbidity) and are involved in the wine ageing processes. This review summarises flavonoid synthesis in the grape berry and the impact of environmental factors on the accumulation rate during ripening of each of the flavonoids.  The impact of the accumulated flavonoids in grapes and the resulting impact on the sensorial aspects of the wine are also discussed.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84707448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Gibberellic Acid (GA3) Inflorescence Application on Content of Bioactive Compounds and Antioxidant Potential of Grape (Vitis L.) ‘Einset Seedless’ Berries","authors":"M. Kapłan, A. Najda, Kamila Klimek, A. Borowy","doi":"10.21548/40-1-3004","DOIUrl":"https://doi.org/10.21548/40-1-3004","url":null,"abstract":"Gibberellic acid (GA3) is a plant growth regulator widely used in the cultivation of seedless grape varieties to increase their yield. Hormonisation treatment has beneficial effects on yield size and quality, yet its influence on the level of biologically active compounds and grape antioxidant activity has not yet been studied extensively yet. Clusters of 11-year-old ‘Einset Seedless’ grapevines trained according to the single Guyot pruning style were sprayed with GA3 at 100, 200 or 300 mg/L dose once, twice or three times.  Fruit harvested on 25 September were immediately examined for acidity, extract content, biologically active substances and antioxidant capacity using the DPPH test. In addition, correlations occurring between some parameters measured were calculated. Hormonisation had a negative effect on the content of extract, flavonoids and ascorbic acid, while it had no effect on the anthocyanin level. The antioxidant activity determined by the DPPH assay depended on dose and the number of treatments, and the analysed parameters were shown to decrease significantly with increasing application number. Gibberellic acid at 100 and 300 mg/L application rates had a significantly increased DPPH level compared to the control and 200 mg/L dose. The single GA3 treatment, and when applied three times, and application rates at 100 and 200 mg/L were shown to have a significant influence on phenolic acid content. The level of tannins after a single GA3 treatment and a 300 mg/L dose increased significantly.","PeriodicalId":21860,"journal":{"name":"South African Journal of Enology & Viticulture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89992332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}