Gonzalo Garrido‐Bañuelos, A. Buica, E. Sharp, A. D. Villiers, W. D. Toit
Colour and phenolic stability during ageing are influenced by the levels of distinct classes of phenolics in young red wines. The ratios between different classes of phenolic compounds also determine the colour and phenolic development of red wines. The present study evaluated the impact of forced oxidation on different anthocyanin/tannin (A/T) extracts and its consequent effect on the colour and phenolic evolution over time. The results showed that higher contents of seed tannins could enhance phenolic polymer formation, especially in the presence of oxygen. The addition of oxygen seemed to favour certain polymerisation reactions between tannins, leading to higher concentrations of monomeric anthocyanins in solution. A slower oxygen consumption was also observed as the phenolic composition of the wine-like extract evolved over time.
{"title":"he Impact of Different Tannin to Anthocyanin Ratios and of Oxygen on the Phenolic Polymerisation Over Time in a Wine-like Solution","authors":"Gonzalo Garrido‐Bañuelos, A. Buica, E. Sharp, A. D. Villiers, W. D. Toit","doi":"10.21548/40-2-3375","DOIUrl":"https://doi.org/10.21548/40-2-3375","url":null,"abstract":"Colour and phenolic stability during ageing are influenced by the levels of distinct classes of phenolics in young red wines. The ratios between different classes of phenolic compounds also determine the colour and phenolic development of red wines. The present study evaluated the impact of forced oxidation on different anthocyanin/tannin (A/T) extracts and its consequent effect on the colour and phenolic evolution over time. The results showed that higher contents of seed tannins could enhance phenolic polymer formation, especially in the presence of oxygen. The addition of oxygen seemed to favour certain polymerisation reactions between tannins, leading to higher concentrations of monomeric anthocyanins in solution. A slower oxygen consumption was also observed as the phenolic composition of the wine-like extract evolved over time.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44861918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grapes are one of the most commonly produced fruit crops in the world and are consumed as table grapes, wine grapes and dried grapes. In line with consumer demands, seedlessness continues to be an important feature that increases the chances of marketing grapes. Nearly all of the dried grapes that are offered to the world markets are seedless grapes. In addition, the demand for seedless varieties has increased steadily in the table grape trade over the years. Therefore, the production of new seedless grape varieties with large berries that are suitable for table consumption is one of the important goals of breeding studies in viticulture. In this study, recently bred and released new seedless grape varieties are briefly introduced, seedless grape breeding methods are summarised, and the latest developments in breeding methods are explained.
{"title":"Recent Developments in Seedless Grapevine Breeding","authors":"M. Akkurt, H. Tahmaz, S. Veziroglu","doi":"10.21548/40-2-3342","DOIUrl":"https://doi.org/10.21548/40-2-3342","url":null,"abstract":"Grapes are one of the most commonly produced fruit crops in the world and are consumed as table grapes, wine grapes and dried grapes. In line with consumer demands, seedlessness continues to be an important feature that increases the chances of marketing grapes. Nearly all of the dried grapes that are offered to the world markets are seedless grapes. In addition, the demand for seedless varieties has increased steadily in the table grape trade over the years. Therefore, the production of new seedless grape varieties with large berries that are suitable for table consumption is one of the important goals of breeding studies in viticulture. In this study, recently bred and released new seedless grape varieties are briefly introduced, seedless grape breeding methods are summarised, and the latest developments in breeding methods are explained.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3342","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42203740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marianne McKay, F. Bauer, Valeria Panzeri, L. Mokwena, A. Buica
Malodourous compounds, including volatile phenols (VPs) are frequently found at concentrations below their odour thresholds in wine, and may therefore be considered to present no threat to wine quality. Most investigations into smoke taint quantify compounds by chemical/analytical means, or investigate sensory effects of supra- and peri-threshold contamination in model wine. In this project, twelve wines (submitted by the South African industry as potentially smoke tainted) were screened for VPs using GC-MS, and characterized using descriptive analysis (DA) by a sensory panel highly trained in smoke taint evaluation. Results were compared statistically to elucidate relationships between chemical and sensory characteristics. It was demonstrated, using the combined dataset that concentration and composition of VPs in the wines correlated well with certain sensory attributes. Guaiacol was present in most samples at peri- or suprathreshold levels, but was not correlated with taint unless in combination with other phenols, in which case it was associated with ‘smoky’, ‘ashy’ and ‘herbaceous’ attributes. Wines with supra-threshold levels of VPs showed negative attributes (‘chemical / plastic’, ‘tar / BR’ and ‘medicinal / Elastoplast™’). In some cases, sensory effects (‘earthy / dusty / potato skin’, ‘mouldy / musty’ and ‘cooked vegetables (veg.)’) could not be attributed to supra-threshold VP contamination, and therefore seemed to be due to combinations of VPs at subthreshold levels. Associations between negative attributes and historical bushfire events prior to harvest were found for a number of the wines. This study emphasizes the importance of understanding effects of VPs on wine aroma, and escalating awareness and sensitivity to these issues in the wine industry.
{"title":"Potentially Smoke Tainted Red Wines: Volatile Phenols and Aroma Attributes","authors":"Marianne McKay, F. Bauer, Valeria Panzeri, L. Mokwena, A. Buica","doi":"10.21548/40-2-3270","DOIUrl":"https://doi.org/10.21548/40-2-3270","url":null,"abstract":"Malodourous compounds, including volatile phenols (VPs) are frequently found at concentrations below their odour thresholds in wine, and may therefore be considered to present no threat to wine quality. Most investigations into smoke taint quantify compounds by chemical/analytical means, or investigate sensory effects of supra- and peri-threshold contamination in model wine. In this project, twelve wines (submitted by the South African industry as potentially smoke tainted) were screened for VPs using GC-MS, and characterized using descriptive analysis (DA) by a sensory panel highly trained in smoke taint evaluation. Results were compared statistically to elucidate relationships between chemical and sensory characteristics. It was demonstrated, using the combined dataset that concentration and composition of VPs in the wines correlated well with certain sensory attributes. Guaiacol was present in most samples at peri- or suprathreshold levels, but was not correlated with taint unless in combination with other phenols, in which case it was associated with ‘smoky’, ‘ashy’ and ‘herbaceous’ attributes. Wines with supra-threshold levels of VPs showed negative attributes (‘chemical / plastic’, ‘tar / BR’ and ‘medicinal / Elastoplast™’). In some cases, sensory effects (‘earthy / dusty / potato skin’, ‘mouldy / musty’ and ‘cooked vegetables (veg.)’) could not be attributed to supra-threshold VP contamination, and therefore seemed to be due to combinations of VPs at subthreshold levels. Associations between negative attributes and historical bushfire events prior to harvest were found for a number of the wines. This study emphasizes the importance of understanding effects of VPs on wine aroma, and escalating awareness and sensitivity to these issues in the wine industry.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41653730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Radovanović, M. Andjelković, B. Arsić, A. Radovanović, L. Gojković-Bukarica
By using cost-effective ultrasonic extraction techniques, bioactive phenolic extracts were obtained from Merlot and Vranac (Vitis vinifera L.) vine and wine waste produced in Serbian wineries. These wastes include vine leaves, grape pomace, seeds, skins and stems, which can find further use in the food and pharmacology industries as preservatives against microbes. The extracts showed strong scavenging free radical activity (EC50 from 0.37 to 2.02 mg/L), which was in very good correlation with the total polyphenol content. Strong antimicrobial activity was found against six Gram-positive and five Gram-negative bacterial strains, and against the yeast Candida albicans. The principal component and agglomerative hierarchical clustering analyses performed were shown to be good for grouping and distinguishing the results from the vine and wine by-products (leaves and seeds) from both investigated grape varieties based on the content of various polyphenolic classes, and antioxidant and antimicrobial activities. The valorisation of the grape by-products is consistent with the concept of a sustainable and environmentally oriented wine industry and provides an important economic advantage.
{"title":"Cost-effective Ultrasonic Extraction of Bioactive Polyphenols from Vine and Wine Waste in Serbia","authors":"V. Radovanović, M. Andjelković, B. Arsić, A. Radovanović, L. Gojković-Bukarica","doi":"10.21548/40-2-3215","DOIUrl":"https://doi.org/10.21548/40-2-3215","url":null,"abstract":"By using cost-effective ultrasonic extraction techniques, bioactive phenolic extracts were obtained from Merlot and Vranac (Vitis vinifera L.) vine and wine waste produced in Serbian wineries. These wastes include vine leaves, grape pomace, seeds, skins and stems, which can find further use in the food and pharmacology industries as preservatives against microbes. The extracts showed strong scavenging free radical activity (EC50 from 0.37 to 2.02 mg/L), which was in very good correlation with the total polyphenol content. Strong antimicrobial activity was found against six Gram-positive and five Gram-negative bacterial strains, and against the yeast Candida albicans. The principal component and agglomerative hierarchical clustering analyses performed were shown to be good for grouping and distinguishing the results from the vine and wine by-products (leaves and seeds) from both investigated grape varieties based on the content of various polyphenolic classes, and antioxidant and antimicrobial activities. The valorisation of the grape by-products is consistent with the concept of a sustainable and environmentally oriented wine industry and provides an important economic advantage.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3215","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44349999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grapevine leafroll is the most damaging grapevine virus disease in South Africa, and the primary vector of Grapevine leafroll-associated virus 3 (GLRaV-3) is vine mealybug, Planococcus ficus (Signoret). Preventing re-infection of newly planted, virus-free grapevines is critical to control and prevent the spread of leafroll disease. Results from a previous survey raised concern that mealybugs surviving on leafroll-infected root remnants in the soil could transmit the virus to newly planted grapevines. This study aimed to determine if P. ficus commonly occurs on grapevine roots in the Western Cape Province of South Africa, if and for how long it can survive on remnant roots in soil, and if it can transmit GLRaV-3 to healthy grapevines after surviving on remnant roots. Surveys to determine the occurrence of mealybugs on grapevine roots were conducted at different times of the growing season in vineyards near Robertson, McGregor, Montagu, Somerset West and Malmesbury over three seasons. A field trial was conducted on a sand-clay-loam soil with 23% clay and a sandy-loam soil with 10% clay over 12 months to determine survival of different life stages of vine mealybug confined on root sections from leafroll-infected Pinotage/R110 grapevines. Results indicate that P. ficus does not readily occur on grapevine roots in the Western Cape, and that it does not survive well on root remnants of grapevines for any length of time. Implications for planting virus-free grapevines in soil where leafroll-infected vines were removed, are discussed.
{"title":"Survival of vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), on grapevine root remnants in soil in the Western Cape Province, South Africa","authors":"E. Allsopp, J. Fourie","doi":"10.21548/40-2-3305","DOIUrl":"https://doi.org/10.21548/40-2-3305","url":null,"abstract":"Grapevine leafroll is the most damaging grapevine virus disease in South Africa, and the primary vector of Grapevine leafroll-associated virus 3 (GLRaV-3) is vine mealybug, Planococcus ficus (Signoret). Preventing re-infection of newly planted, virus-free grapevines is critical to control and prevent the spread of leafroll disease. Results from a previous survey raised concern that mealybugs surviving on leafroll-infected root remnants in the soil could transmit the virus to newly planted grapevines. This study aimed to determine if P. ficus commonly occurs on grapevine roots in the Western Cape Province of South Africa, if and for how long it can survive on remnant roots in soil, and if it can transmit GLRaV-3 to healthy grapevines after surviving on remnant roots. Surveys to determine the occurrence of mealybugs on grapevine roots were conducted at different times of the growing season in vineyards near Robertson, McGregor, Montagu, Somerset West and Malmesbury over three seasons. A field trial was conducted on a sand-clay-loam soil with 23% clay and a sandy-loam soil with 10% clay over 12 months to determine survival of different life stages of vine mealybug confined on root sections from leafroll-infected Pinotage/R110 grapevines. Results indicate that P. ficus does not readily occur on grapevine roots in the Western Cape, and that it does not survive well on root remnants of grapevines for any length of time. Implications for planting virus-free grapevines in soil where leafroll-infected vines were removed, are discussed.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3305","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43132723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of fertilisation can reverberate from grapes through to wines. In wine, non-volatile compounds mainly influence the taste and flavour of wines, while volatile compounds play an important role in the aromatic expression. This review includes information on the presence of non-volatile and volatile compounds reportedly affected by nitrogen and sulphure foliar fertilisation, (bio)synthesis, and evolution throughout winemaking, their chemical properties, and their implications. The second part presents the status of the research on elucidating the influence and contribution of foliar fertilisation practices on the chemical compounds throughout winemaking, from the grape to the wine.
{"title":"Nitrogen and Sulphur Foliar Fertilisation","authors":"F. Bruwer, W. D. Toit, A. Buica","doi":"10.21548/40-2-3281","DOIUrl":"https://doi.org/10.21548/40-2-3281","url":null,"abstract":"The effects of fertilisation can reverberate from grapes through to wines. In wine, non-volatile compounds mainly influence the taste and flavour of wines, while volatile compounds play an important role in the aromatic expression. This review includes information on the presence of non-volatile and volatile compounds reportedly affected by nitrogen and sulphure foliar fertilisation, (bio)synthesis, and evolution throughout winemaking, their chemical properties, and their implications. The second part presents the status of the research on elucidating the influence and contribution of foliar fertilisation practices on the chemical compounds throughout winemaking, from the grape to the wine.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46654865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study aimed to elucidate the amino acid profile of a number of grapevine cultivars relevant to the South African wine industry using 738 grape must samples obtained during the 2016 and 2017 harvests. Proline and arginine were found to be the most abundant amino acids, with an average of 697.69 mg/L for proline (range 33.22-3445.43 mg/L) and 388.35 mg/L for arginine (range 13.56-1616.56 mg/L) across all vintages, regions, and cultivars. At the other extreme, ornithine (2.01 mg/L), glycine (3.28 mg/L), methionine (3.64 mg/L) and lysine (3.91 mg/L) were found to have the lowest concentrations, both in terms of the overall average, as well as per cultivar. Furthermore, the data were used to demonstrate how characteristic the amino acid profile is of a particular group (red or white) or cultivar. Cultivars were predicted based on their average amino acid concentrations using general discriminant analysis (GDA) and the best subset principle. For white musts, Chardonnay showed the highest prediction accuracy (100%), and Pinotage (75%) for red cultivars. Overall, the white cultivars included in this study were more accurately distinguished from one another (75.6%) compared to the red (60.1%). This predictive ability was subsequently compared to the accuracy of predicting cultivars based on only the arginine and proline concentrations as well as the ratio between the two. The use of only these amino acids as well as the addition of the proline/arginine ratio as a predictor variable did not offer satisfactory discriminatory power between either white or red cultivars.
{"title":"Grape Must Profiling And Cultivar Discrimination Based On Amino Acid Composition And General Discriminant Analysis With Best Subset","authors":"Gabriella Petrovic, J. Aleixandré-Tudo, A. Buica","doi":"10.21548/40-2-3373","DOIUrl":"https://doi.org/10.21548/40-2-3373","url":null,"abstract":"The present study aimed to elucidate the amino acid profile of a number of grapevine cultivars relevant to the South African wine industry using 738 grape must samples obtained during the 2016 and 2017 harvests. Proline and arginine were found to be the most abundant amino acids, with an average of 697.69 mg/L for proline (range 33.22-3445.43 mg/L) and 388.35 mg/L for arginine (range 13.56-1616.56 mg/L) across all vintages, regions, and cultivars. At the other extreme, ornithine (2.01 mg/L), glycine (3.28 mg/L), methionine (3.64 mg/L) and lysine (3.91 mg/L) were found to have the lowest concentrations, both in terms of the overall average, as well as per cultivar. Furthermore, the data were used to demonstrate how characteristic the amino acid profile is of a particular group (red or white) or cultivar. Cultivars were predicted based on their average amino acid concentrations using general discriminant analysis (GDA) and the best subset principle. For white musts, Chardonnay showed the highest prediction accuracy (100%), and Pinotage (75%) for red cultivars. Overall, the white cultivars included in this study were more accurately distinguished from one another (75.6%) compared to the red (60.1%). This predictive ability was subsequently compared to the accuracy of predicting cultivars based on only the arginine and proline concentrations as well as the ratio between the two. The use of only these amino acids as well as the addition of the proline/arginine ratio as a predictor variable did not offer satisfactory discriminatory power between either white or red cultivars.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-2-3373","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48055911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lidia Sas Paszt, S. Głuszek, E. Derkowska, B. Sumorok, J. Lisek, P. Trzciński, A. Lisek, M. Frąc, M. Sitarek, Michał Przybył
The aim of this study was to determine the influence of different bioproducts on the occurrence of arbuscular mycorrhizal fungi (AMF) in the roots of ‘Solaris’ and ‘Regent’ grapevine cultivars. The following bioproducts were used, alone or with mineral fertilization (NPK): Ausma, Bioilsa, manure and BF Ekomix. The highest mycorrhizal frequency was recorded in the roots of ‘Solaris’ after applying the bioproduct Ausma. For the ‘Regent’ cultivar, the highest mycorrhizal frequency was found in the plants treated with Ausma, BF Ekomix and manure. Colonization of grapevine roots by AM fungi was limited by mineral fertilization. After the combined use of bioproducts and mineral fertilizers, there was observed a tendency for minimized negative effect of mineral fertilization on the formation of arbuscular mycorrhizal fungi.
{"title":"Occurrence of arbuscular mycorrhizal fungi in the roots of two grapevine cultivars in response to bioproducts","authors":"Lidia Sas Paszt, S. Głuszek, E. Derkowska, B. Sumorok, J. Lisek, P. Trzciński, A. Lisek, M. Frąc, M. Sitarek, Michał Przybył","doi":"10.21548/40-1-3115","DOIUrl":"https://doi.org/10.21548/40-1-3115","url":null,"abstract":"The aim of this study was to determine the influence of different bioproducts on the occurrence of arbuscular mycorrhizal fungi (AMF) in the roots of ‘Solaris’ and ‘Regent’ grapevine cultivars. The following bioproducts were used, alone or with mineral fertilization (NPK): Ausma, Bioilsa, manure and BF Ekomix. The highest mycorrhizal frequency was recorded in the roots of ‘Solaris’ after applying the bioproduct Ausma. For the ‘Regent’ cultivar, the highest mycorrhizal frequency was found in the plants treated with Ausma, BF Ekomix and manure. Colonization of grapevine roots by AM fungi was limited by mineral fertilization. After the combined use of bioproducts and mineral fertilizers, there was observed a tendency for minimized negative effect of mineral fertilization on the formation of arbuscular mycorrhizal fungi.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/40-1-3115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42563286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the special climate conditions in the Qingtongxia region, grapes are high in sugar and low in titratable acidity from the stages of ripening. Therefore, the common methods used for determining the maturity of grapes, which depend on the ratio of sugar and titratable acidity in other regions, are inappropriate in Qingtongxia. This research was done in order to seek for a simple and convenient method of determining the optimal harvest time of grapes, further providing some theoretical basis for improving the quality of wine in Qingtongxia. Phenolic contents and some basic physico-chemical parameters of Merlot and Pinot Noir were evaluated during different ripening stages. The results showed that a different harvest time significantly affects the phenolic contents and physico-chemical parameters of Merlot and Pinot Noir. The total contents of anthocyanins in skins and total contents of phenolic in seeds was screen out as two important indexes to evaluate the maturity of polyphenols, in order to better improve the quality of grape and wine.
{"title":"Effects of Different Harvest Times on the Maturity of Polyphenols in Two Red Wine Grape Cultivars (Vitis vinifera L.) in Qingtongxia (China)","authors":"Y. Zhou, P. Su, H. Yin, Z. Dong, L. Yang, C. Yuan","doi":"10.21548/40-2-2770","DOIUrl":"https://doi.org/10.21548/40-2-2770","url":null,"abstract":"Due to the special climate conditions in the Qingtongxia region, grapes are high in sugar and low in titratable acidity from the stages of ripening. Therefore, the common methods used for determining the maturity of grapes, which depend on the ratio of sugar and titratable acidity in other regions, are inappropriate in Qingtongxia. This research was done in order to seek for a simple and convenient method of determining the optimal harvest time of grapes, further providing some theoretical basis for improving the quality of wine in Qingtongxia. Phenolic contents and some basic physico-chemical parameters of Merlot and Pinot Noir were evaluated during different ripening stages. The results showed that a different harvest time significantly affects the phenolic contents and physico-chemical parameters of Merlot and Pinot Noir. The total contents of anthocyanins in skins and total contents of phenolic in seeds was screen out as two important indexes to evaluate the maturity of polyphenols, in order to better improve the quality of grape and wine.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42633233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interaction studies are some of the most interesting sensory experiments that highlight the effect of composition on wine perception. The use of single compounds, viz. an ester (ethyl hexanoate), a terpene (linalool) and a thiol (3-mercaptohexanol, 3MH), which have previously been shown to be representative of Chenin Blanc wines, resulted in typical descriptors for these compounds, such as ‘apple, ‘floral’ and ‘guava’ respectively. Interaction effects were observed between the compounds, and these were reflected in both the nature and the level of attributes generated. Additionally, interaction effects between the compounds (singles and combinations) and the wine matrix indicated that the latter plays an important role in the perception of wine aromas. The use of a dearomatised neutral wine base added an extra dimension to this study, which usually is done in a simpler matrix, such as a model wine.
{"title":"Interaction Effects of 3-Mercaptohexan-1-ol (3MH), Linalool and Ethyl Hexanoate on the Aromatic Profile of South African Dry Chenin blanc Wine by Descriptive Analysis (DA)","authors":"Christine Wilson, J. Brand, W. D. Toit, A. Buica","doi":"10.21548/39-2-3165","DOIUrl":"https://doi.org/10.21548/39-2-3165","url":null,"abstract":"Interaction studies are some of the most interesting sensory experiments that highlight the effect of composition on wine perception. The use of single compounds, viz. an ester (ethyl hexanoate), a terpene (linalool) and a thiol (3-mercaptohexanol, 3MH), which have previously been shown to be representative of Chenin Blanc wines, resulted in typical descriptors for these compounds, such as ‘apple, ‘floral’ and ‘guava’ respectively. Interaction effects were observed between the compounds, and these were reflected in both the nature and the level of attributes generated. Additionally, interaction effects between the compounds (singles and combinations) and the wine matrix indicated that the latter plays an important role in the perception of wine aromas. The use of a dearomatised neutral wine base added an extra dimension to this study, which usually is done in a simpler matrix, such as a model wine.","PeriodicalId":21894,"journal":{"name":"South African Journal of Enology and Viticulture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21548/39-2-3165","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47531749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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