Yeast derivatives: a promising alternative for white wine oxidation prevention

In the previous decade, the use of Yeast Derivatives (YD) was proposed as a new strategy to control wine oxidation (Comuzzo et al., 2015). These products are obtained from yeasts by autolytic or hydrolytic processes and then dried to obtain the commercial products. The aim of this work was to carry out a preliminary investigation of commercial YDs with different compositions in order to (i) compare their capacity to prevent white wine oxidation in comparison with conventional treatment using SO2, and (ii) evaluate their impact on wine quality

Les fonds anciens des Archives communales aujourd'hui

Die alten Bestânde der Gemeindearchive. Im Verfolge einer an die Gemeindearchive betreffs ihrer alten Bestände gerichteten Umfrage zieht der Artikel zunächst die Bilanz aus den Antworten. Letztere sind zum grössten Teil negativ und bezeugen von Seiten sowohl der für die Gemeindearchive verantwortlichen Personen, als auch der Benutzer, einen äusserst starken Interesse-mangel an diesen Beständen. Es gibt zahlreiche Gründe für dieses schwindende Interesse : die Archive werden meistens von Bibliothekaren verwaltet ; man sieht in den Verantwortlichen keine Historiker, sondern Dokumentare ; die Findbehelfe sind nicht angepasst ; es fehlt den Gemeindearchivaren an Fachbildung oder an Mitteln, um sich an die Ordnung der alten Bestände heranzuwagen oder sie wieder aufzugreifen. Einige ausfuhrlicher dargestellte Einzelfälle zeigen indessen Gemeindearchivare, die in ihrer Rolle als Hüter des geschichtlichen Erbes eine bemerkenswerte Tätigkeit entfalten, in : Blois, Marseille, Nizza, Pau, Poitiers, Strassburg und Troyes. Diese ailes in allem unausgeglichene Lage lädt zum Nachdenken liber eine demnächstige weitergespannte Umfrage zu diesem Thema ein.Historical documents in municipal archives. This article is the result of a questionnaire circulated among French Municipal Archives about their keepings older than 1789 (" fonds anciens "). The answers were mainly negative, stating an extreme disinterest for these documents, both from persons responsible of municipal archives and from users. There are various reasons for this disinterest : many municipal archives are managed not by archivists, but by librarians ; many of these are more documentalists than historians ; few archives have adequate finding aids ; many municipal archivists lack specialized training and adequate means to deal with the processing of old documents. Nevertheless, in some cases there are municipal archivists who play actively their role of keepers of historical heritage, for instance at Blois, Marseille, Nice, Pau, Poitiers, Strasbourg, Troyes. This unbalanced situation should induce us to a more detailed study on the subject.Documentos histôricos en los archivos municipales. El articulo es el compendio de las respuestas a un cuestionario enviado a los archi-veros municipales de Francia relativo a sus documentos anteriores a 1789 («Fonds anciens »). Las respuestas fueron en mayor parte negativas, reflejando una considérable falta de interés para estos documentas, de parte de los responsables de los archivos y de los usuarios. Varias causas pueden descubrirse : muchos archivos municipales son administrados no por archiveras, sino por bibliotecarios ; muchos de ellos son mas documentalistas que historiadores ; pocos archivos municipales tienen instrumentes de investigaciôn adecuados ; muchos archiveros municipales carecen una formacion especializada y recursos adecuados para el tratamiento de douementos histdricos. Sin embargo, en varios casos los archiveros municipales desempenan activamente su papel de con-servadores, del patrimonio histôrico de las ciudades por ejemplo a Blois, Marseille, Nice, Pau, Poitiers, Strasbourg, Troyes. Esta situaciôn desequilibrada necesitaria un estudio mas detallado del asunto.BIBOLET Françoise, Massot Mireille, Ramière Arnaud. Les fonds anciens des Archives communales aujourd'hui. In: La Gazette des archives, n°125-126, 1984. Les archives historiques : archives d’hier, histoire de demain. pp. 179-206

Antioxidant activity of yeast derivatives: Evaluation of their application to enhance the oxidative stability of white wine

International audienceMaintaining wine oxidative stability and reducing SO 2 addition remains a challenge in white winemaking. This study aimed to evaluate the antioxidant capacity of two yeast derivatives (YDs) with a specific composition: one was rich in reducing compounds, including glutathione (YD R), and the other was rich in lipid compounds (YD L). Both YDs were evaluated for their antiradical activity in model wine solution (by the DPPH method) and for their capacity to consume oxygen in model wine solution and in white wine. Antiradical activity in both matrixes and oxygen consumption rate in wine were higher for YD L than for YD R. However, the addition of YD R to wine limited the production of acetaldehyde and preserved glutathione content to a greater extent after wine oxygenation. The sensory analysis confirmed that both YDs, in particular YD L , limited the occurrence of oxidation off-odours when no SO 2 was added. These data suggest that the use of YDs could be effectively implemented in low-sulfite winemaking in order to improve the antioxidant protection of white wine

The colloidal stabilization of young red wine by Acacia senegal gum: The involvement of the protein backbone from the protein-rich arabinogalactan-proteins

The arabinogalactan-proteins (AGPs) from Acacia senegal gum are used as protective colloid in young red wines to prevent the precipitation of the coloring matter. Usually, Acacia senegal gum is chosen based on its efficiency to stabilize iron hexacyanoferrate salts in hydro-alcoholic solution. In this study, the protective activity of Acacia senegal gum and its macromolecular fractions (HIC–F1, HIC–F2 and HIC–F3), separated according to their hydrophobicity, towards the precipitation of iron hexacyanoferrate salts and polyphenols in hydro-alcoholic solutions are reported. AGPs prevent the colloidal instability of both iron hexacyanoferrate salts and polyphenols in “model” hydro-alcoholic solutions and young red wine with a good correlation between results obtained on both systems. This result strengthens the use of iron hexacyanoferrate salts (hydro-alcoholic – mineral test) for the evaluation of the protective activity of A. senegal gum in young red wine. The precipitation of iron hexacyanoferrate salts is avoided by the electrostatic binding of Ca2+, the driver of the instability, with the negatively charged carried by amino-acids from the protein backbone or both by amino acids and uronic acid monosaccharides localized close to the protein backbone of AGPs. The protective activity closely depends on the protein content of AGPs in both iron hexacyanoferrate salts and polyphenols hydro-alcoholic solutions: the more they are rich in proteins, the more their colloidal stabilizing efficiency is (HIC–F3>HIC–F2>HIC–F1). The differences observed in the protective activity between AGPs from the three HIC fractions are relied not only to their protein content but also to their related rate of glycosylation that modulates the protein accessibility to its environment, then their physicochemical properties as their hydrophobic behavior

Identification and quantification of resolubilised polyphenols from fining precipitation

The aim of this study was to better understand the colloidal phenomenon involved in the fining process and to determine how many polyphenols are impacted in this process. Different types and compositions of fining agent were used to fine the wine. Some of them were pure and based on animal proteins and plant proteins, while others comprised a mixture of different matter, like PVPP and plant proteins, or PVPP, plant proteins and bentonite. Before and after fining, five different analyses were performed on the wine to characterise the polyphenolic composition and content. In order to determine polyphenol loss more precisely during fining, a new method was developed to quantify and characterise polyphenol precipitate using fining agents. This new method allowed us to find some drastic differences between the fining agents in term of total polyphenol precipitation, as well as in the composition of the precipitated compounds. Indeed, a group of anthocyanins present in low levels in wine (i.e., p-coumaroylated anthocyanins) became the most represented in the fining precipitate. Similarly, differences were also observed between the fining agents in the composition of precipitated condensed tannins. Fining agents without PVPP did not precipitate monomeric or dimeric flavan-3-ol or crown tannins. Some differences were also observed between the fining agent composed of plant-derived protein and that comprising gelatin. © 2023, International Viticulture and Enology Society. All rights reserved

Potential diagnostic biomarkers of Ulcerative Colitis-associated colorectal dysplasia

Biomarkers of Colorectal Dysplasi

Research on the origin and the side effects of chitosan stabilizing properties in wine

Research on the origin and the side effects of chitosan stabilizing properties in wine. Applied Natural Products : From Discoveries To Innovation