Polyphenol composition, an important component of grape quality, is strongly influenced by fruit ... more Polyphenol composition, an important component of grape quality, is strongly influenced by fruit microclimate. However, information relies exclusively on whole berry data and the underlying response functions to microenvironment variablesremainessentiallyunknown.Theaimofthisstudywasthereforetoanalyzethebiochemicalcompositionofgrapesat bothbunchandberryscales,inrelationwithmicroclimate. Methods and results : Whole berries and berry halves were sampled in mature defoliated bunches from two neighboring Bordeaux vineyards with contrasting row orientations (Vitis vinifera cv. Merlot). Flavonoid and amino-acid contents were analyzedbyHPLCmethods.Themainsourcesofvariationwerebunchazimuth,berryexposureand,onlyinSouth-exposed bunches,berryside.Modelswereusedtoestimateradiationattheberrysurfaceandtemperature.Intenseeffectsofbunchside andberrysideontotalflavonolandanthocyaninconcentrationswereobserved.Theseresultswereallconsistentatbothbunch andberryscales.However,themostintenseeffectswereobservedatberryscaleandmitigatedbyscalingupfromberryto bunch. Conclusion:Totalflavonolconcentrationsintheberryskinexhibitedaclearpositivelinearrelationshipwithsolarradiation. Thelargeheterogeneityofcompositionatberryscaleisconsistentwiththebetterknownheterogeneityatbunchscale. Significance and impact of the study:Modelsandoriginalresponsefunctionstomicroclimatecouldhelpoptimizevineyard managementandgraperipening.
Le Groupe Amorim, né du liège en 1870 au Portugal, a fondé les bases de son développement sur cet... more Le Groupe Amorim, né du liège en 1870 au Portugal, a fondé les bases de son développement sur cette extraordinaire matière première, à travers la production de cet humble mais inséparable compagnon du Vin : le bouchon de liège. Notre volonté de servir la cause du vin s'est toujours exprimée dans la recherche technologique sur la lière liège, base de notre activité. En 1992, nous avons souhaité aller plus loin et nous engager davantage aux cotés des chercheurs en oenologie en créant l'Académie Amorim, un lieu de rencontre d'échange entre oenologues, ingénieurs, professeurs, sommeliers, auteurs, artistes… tous animés d'une même passion du Vin. Chaque année, notre Académie encourage et soutient la recherche en oenologie par la remise d'un Prix à un chercheur ou à une équipe de chercheurs ayant fait paraître des travaux significatifs qui concourent à la défense et à la promotion de la qualité du Vin. Que soient ici saluées les personnalités, membres de cette Académie, qui contribuent si généreusement à cette mission. Je formule le voeux que cette collection, dédiée aux Lauréats du Grand Prix de l'Académie, devienne, au l des ans, une référence et la mémoire vivante des efforts et des travaux engagés dans le monde entier pour servir la noble cause du Vin.
This detailed study observed the yeasts present in the ecological niche of "wine must". The dynam... more This detailed study observed the yeasts present in the ecological niche of "wine must". The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. The non-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 10 4-10 5 CFU/mL during cold maceration. The population increased to a maximum of 10 6-10 7 CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 10 3-10 4 CFU/ mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.
The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species... more The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species. Specific oligonucleotide primers for real-time quantitative PCR(QPCR) were designed to analyse several important non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.) and Saccharomyces spp. in fresh wine must, during fermentation and in the finished wine. The specificity of all primer couples for their target yeast species were validated and the QPCR methods developed were compared with a classic approach of colony identification by RFLP-ITS-PCR on cultured samples. Once the methods had been developed and validated, they were used to study these non-Saccharomyces yeasts in wine samples and to monitor their dynamics throughout the fermentation process. This study confirms the usefulness and the relevance of QPCR for studying non-Saccharomyces yeasts in the complex yeast ecosystem of grape must and wine.
... Grand Prix 2008 - Elise SARRAZIN « Recherches sur l'arôme des vins liquoreux de pourritur... more ... Grand Prix 2008 - Elise SARRAZIN « Recherches sur l'arôme des vins liquoreux de pourriture noble issus des cépages Sémillon et Sauvignon ... Grand Prix 1999 - Isabelle CUTZACH-BILLARD «Etude sur l'arôme des vins doux naturels non muscatés au cours de leur élevage et ...
This detailed study observed the yeasts present in the ecological niche of "wine must". The dynam... more This detailed study observed the yeasts present in the ecological niche of "wine must". The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. The non-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 10 4 -10 5 CFU/mL during cold maceration. The population increased to a maximum of 10 6 -10 7 CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 10 3 -10 4 CFU/ mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.
Several studies have reported the beneficial influence of non-Saccharomyces yeasts and their pote... more Several studies have reported the beneficial influence of non-Saccharomyces yeasts and their potential applications in the wine industry, mainly in mixed-culture fermentation with S. cerevisiae. The potential impact of 15 non-Saccharomyces strains from 7 species on 4-methyl-4-sulfanylpentan-2-one (4MSP) and 3-sulfanylhexan-1-ol (3SH) release in model medium and Sauvignon Blanc must was evaluated after partial fermentation. Whereas the impact of non-Saccharomyces on 4MSP release in both media was low, some M. pulcherrima, T. delbrueckii and K. thermotolerans strains had a high capacity to release 3SH, despite their minimal fermentation activity. As previously demonstrated for Saccharomyces yeast, this contribution is strain dependant. Taking into account their dynamic and quantitative presence during the whole process, the real impact of non-Saccharomyces yeast on 4MSP and 3SH release was evaluated using a recreated community simulating the yeast ecosystem. Our results revealed a positive impact on 3SH release in Sauvignon Blanc wines by promoting non-Saccharomyces yeast activity and delaying the growth of S. cerevisiae. Some non-Saccharomyces yeast strains are capable of making a positive contribution to volatile thiol release in wines, essentially during the prefermentation stage in winemaking, when this microbiological sub-population is dominant.
The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species... more The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species. Specific oligonucleotide primers for real-time quantitative PCR(QPCR) were designed to analyse several important non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.) and Saccharomyces spp. in fresh wine must, during fermentation and in the finished wine. The specificity of all primer couples for their target yeast species were validated and the QPCR methods developed were compared with a classic approach of colony identification by RFLP-ITS-PCR on cultured samples. Once the methods had been developed and validated, they were used to study these non-Saccharomyces yeasts in wine samples and to monitor their dynamics throughout the fermentation process. This study confirms the usefulness and the relevance of QPCR for studying non-Saccharomyces yeasts in the complex yeast ecosystem of grape must and wine.
Polyphenol composition, an important component of grape quality, is strongly influenced by fruit ... more Polyphenol composition, an important component of grape quality, is strongly influenced by fruit microclimate. However, information relies exclusively on whole berry data and the underlying response functions to microenvironment variablesremainessentiallyunknown.Theaimofthisstudywasthereforetoanalyzethebiochemicalcompositionofgrapesat bothbunchandberryscales,inrelationwithmicroclimate. Methods and results : Whole berries and berry halves were sampled in mature defoliated bunches from two neighboring Bordeaux vineyards with contrasting row orientations (Vitis vinifera cv. Merlot). Flavonoid and amino-acid contents were analyzedbyHPLCmethods.Themainsourcesofvariationwerebunchazimuth,berryexposureand,onlyinSouth-exposed bunches,berryside.Modelswereusedtoestimateradiationattheberrysurfaceandtemperature.Intenseeffectsofbunchside andberrysideontotalflavonolandanthocyaninconcentrationswereobserved.Theseresultswereallconsistentatbothbunch andberryscales.However,themostintenseeffectswereobservedatberryscaleandmitigatedbyscalingupfromberryto bunch. Conclusion:Totalflavonolconcentrationsintheberryskinexhibitedaclearpositivelinearrelationshipwithsolarradiation. Thelargeheterogeneityofcompositionatberryscaleisconsistentwiththebetterknownheterogeneityatbunchscale. Significance and impact of the study:Modelsandoriginalresponsefunctionstomicroclimatecouldhelpoptimizevineyard managementandgraperipening.
Le Groupe Amorim, né du liège en 1870 au Portugal, a fondé les bases de son développement sur cet... more Le Groupe Amorim, né du liège en 1870 au Portugal, a fondé les bases de son développement sur cette extraordinaire matière première, à travers la production de cet humble mais inséparable compagnon du Vin : le bouchon de liège. Notre volonté de servir la cause du vin s'est toujours exprimée dans la recherche technologique sur la lière liège, base de notre activité. En 1992, nous avons souhaité aller plus loin et nous engager davantage aux cotés des chercheurs en oenologie en créant l'Académie Amorim, un lieu de rencontre d'échange entre oenologues, ingénieurs, professeurs, sommeliers, auteurs, artistes… tous animés d'une même passion du Vin. Chaque année, notre Académie encourage et soutient la recherche en oenologie par la remise d'un Prix à un chercheur ou à une équipe de chercheurs ayant fait paraître des travaux significatifs qui concourent à la défense et à la promotion de la qualité du Vin. Que soient ici saluées les personnalités, membres de cette Académie, qui contribuent si généreusement à cette mission. Je formule le voeux que cette collection, dédiée aux Lauréats du Grand Prix de l'Académie, devienne, au l des ans, une référence et la mémoire vivante des efforts et des travaux engagés dans le monde entier pour servir la noble cause du Vin.
This detailed study observed the yeasts present in the ecological niche of "wine must". The dynam... more This detailed study observed the yeasts present in the ecological niche of "wine must". The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. The non-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 10 4-10 5 CFU/mL during cold maceration. The population increased to a maximum of 10 6-10 7 CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 10 3-10 4 CFU/ mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.
The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species... more The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species. Specific oligonucleotide primers for real-time quantitative PCR(QPCR) were designed to analyse several important non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.) and Saccharomyces spp. in fresh wine must, during fermentation and in the finished wine. The specificity of all primer couples for their target yeast species were validated and the QPCR methods developed were compared with a classic approach of colony identification by RFLP-ITS-PCR on cultured samples. Once the methods had been developed and validated, they were used to study these non-Saccharomyces yeasts in wine samples and to monitor their dynamics throughout the fermentation process. This study confirms the usefulness and the relevance of QPCR for studying non-Saccharomyces yeasts in the complex yeast ecosystem of grape must and wine.
... Grand Prix 2008 - Elise SARRAZIN « Recherches sur l'arôme des vins liquoreux de pourritur... more ... Grand Prix 2008 - Elise SARRAZIN « Recherches sur l'arôme des vins liquoreux de pourriture noble issus des cépages Sémillon et Sauvignon ... Grand Prix 1999 - Isabelle CUTZACH-BILLARD «Etude sur l'arôme des vins doux naturels non muscatés au cours de leur élevage et ...
This detailed study observed the yeasts present in the ecological niche of "wine must". The dynam... more This detailed study observed the yeasts present in the ecological niche of "wine must". The dynamics and identity of non-Saccharomyces yeasts during the cold maceration and alcoholic fermentation of grape must were investigated under real production conditions in the Bordeaux region. Furthermore, we studied the impact of two oenological parameters on the development and diversity of non-Saccharomyces yeasts during cold maceration: temperature management and the timing of dried yeast addition. The non-Saccharomyces community underwent constant changes throughout cold maceration and alcoholic fermentation. The highly diverse non-Saccharomyces microflora was present at 10 4 -10 5 CFU/mL during cold maceration. The population increased to a maximum of 10 6 -10 7 CFU/mL at the beginning of alcoholic fermentation, then declined again at the end. The population at this point, evaluated at around 10 3 -10 4 CFU/ mL, was shown to be dependent on the timing of yeast inoculation. The choice of temperature was the key factor for controlling the total yeast population growth, as well as the species present at the end of cold maceration. Hanseniaspora uvarum was a major species present in 2005 and 2006, while Candida zemplinina was very abundant in 2006. A total of 19 species were isolated.
Several studies have reported the beneficial influence of non-Saccharomyces yeasts and their pote... more Several studies have reported the beneficial influence of non-Saccharomyces yeasts and their potential applications in the wine industry, mainly in mixed-culture fermentation with S. cerevisiae. The potential impact of 15 non-Saccharomyces strains from 7 species on 4-methyl-4-sulfanylpentan-2-one (4MSP) and 3-sulfanylhexan-1-ol (3SH) release in model medium and Sauvignon Blanc must was evaluated after partial fermentation. Whereas the impact of non-Saccharomyces on 4MSP release in both media was low, some M. pulcherrima, T. delbrueckii and K. thermotolerans strains had a high capacity to release 3SH, despite their minimal fermentation activity. As previously demonstrated for Saccharomyces yeast, this contribution is strain dependant. Taking into account their dynamic and quantitative presence during the whole process, the real impact of non-Saccharomyces yeast on 4MSP and 3SH release was evaluated using a recreated community simulating the yeast ecosystem. Our results revealed a positive impact on 3SH release in Sauvignon Blanc wines by promoting non-Saccharomyces yeast activity and delaying the growth of S. cerevisiae. Some non-Saccharomyces yeast strains are capable of making a positive contribution to volatile thiol release in wines, essentially during the prefermentation stage in winemaking, when this microbiological sub-population is dominant.
The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species... more The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species. Specific oligonucleotide primers for real-time quantitative PCR(QPCR) were designed to analyse several important non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.) and Saccharomyces spp. in fresh wine must, during fermentation and in the finished wine. The specificity of all primer couples for their target yeast species were validated and the QPCR methods developed were compared with a classic approach of colony identification by RFLP-ITS-PCR on cultured samples. Once the methods had been developed and validated, they were used to study these non-Saccharomyces yeasts in wine samples and to monitor their dynamics throughout the fermentation process. This study confirms the usefulness and the relevance of QPCR for studying non-Saccharomyces yeasts in the complex yeast ecosystem of grape must and wine.
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Papers by Katharina Zott