Consecutive alcoholic fermentations of white grape musts with yeasts immobilized on grape skins : effect of biocatalyst storage and SO2 concentration on wine characteristics

Abstract Saccharomyces cerevisiae yeasts, immobilized by natural adsorption on grape skins, were used to carry out the alcoholic fermentation step of a winemaking process. The viability of the immobilized cells was evaluated by the implementation of 7 successive fermentations of a white grape must containing 30 mg/L of SO2. The time to complete alcoholic fermentation, the physicochemical characteristics of the produced wines (ethanol, glycerol, organic acids, volatile compounds, color) and sensory properties were evaluated. A traditional fermentation with free cells was used as control. Three other fermentations were conducted after storage of the immobilized biocatalyst (30 d, 4 oC), the first one in the same conditions of the earlier assays, and the other two with higher amounts of SO2 (60 mg/L, 90 mg/L). Wines produced with immobilized cells presented physicochemical and sensory characteristics similar to those traditionally produced with free cells. After three consecutive fermentations, chromatic characteristics became similar to those of traditional wines, but the fermentation time had been reduced from 7 d to 4 d. The fermentative process and the characteristics of the produced wines were not significantly affected by the use of higher amounts of SO2. Immobilized biocatalysts could be stored at least one month without losing its activity.Zlatina Genisheva gratefully acknowledges FCT (Contract/grant number: SFRH/BD/48186/2009) and the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER, for the financial support of this work

Assessment of grape cluster yield components based on 3D descriptors using stereo vision

NOTICE: this is the author’s version of a work that was accepted for publication in Food Control. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Control, [Volume 50, April 2015, Pages 273–282] DOI 10.1016/j.foodcont.2014.09.004Wine quality depends mostly on the features of the grapes it is made from. Cluster and berry morphology are key factors in determining grape and wine quality. However, current practices for grapevine quality estimation require time-consuming destructive analysis or largely subjective judgment by experts. The purpose of this paper is to propose a three-dimensional computer vision approach to assessing grape yield components based on new 3D descriptors. To achieve this, firstly a partial three-dimensional model of the grapevine cluster is extracted using stereo vision. After that a number of grapevine quality components are predicted using SVM models based on new 3D descriptors. Experiments confirm that this approach is capable of predicting the main cluster yield components, which are related to quality, such as cluster compactness and berry size (R2 > 0.80, p < 0.05). In addition, other yield components: cluster volume, total berry weight and number of berries, were also estimated using SVM models, obtaining prediction R2 of 0.82, 0.83 and 0.71, respectively.This work has been partially funded by the Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria de Espana (INIA - Spanish National Institute for Agriculture and Food Research and Technology) through research project RTA2012-00062-C04-02, support of European FEDER funds, UPV-SP20120276 and AGL2011-23673 project.Ivorra Martínez, E.; Sánchez Salmerón, AJ.; Camarasa Baixauli, JG.; Diago, M.; Tardaguila, J. (2015). Assessment of grape cluster yield components based on 3D descriptors using stereo vision. Food Control. 50:273-282. https://doi.org/10.1016/j.foodcont.2014.09.004S2732825

Grape ripening is regulated by deficit irrigation/elevated temperatures according to cluster position in the canopy

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Use of Schizosaccharomyces strains for wine fermentation? Effect on the wine composition and food safety

Schizosaccharomyceswas initially considered as a spoilage yeast because of the production of undesirable metabolites such as acetic acid, hydrogen sulfide, or acetaldehyde, but it currently seems to be of great value in enology.o ced Nevertheless, Schizosaccharomyces can reduce all of the malic acid in must, leading to malolactic fermentation. Malolactic fermentation is a highly complicated process in enology and leads to a higher concentration of biogenic amines, so the use of Schizosaccharomyces pombe can be an excellent tool for assuring wine safety. Schizosaccharomyces also has much more potential than only reducing the malic acid content, such as increasing the level of pyruvic acid and thus the vinylphenolic pyranoanthocyanin content. Until now, few commercial strains have been available and little research on the selection of appropriate yeast strains with such potential has been conducted. In this study, selected and wild Sc. pombe strains were used along with a Saccharomyces cerevisiae strain to ferment red grape must. The results showed significant differences in several parameters including non-volatile and volatile compounds, anthocyanins, biogenic amines and sensory parameters

Mead production: effect of nitrogen supplementation on growth, fermentation profile and aroma formation by yeasts in mead fermentation

Mead is an alcoholic beverage, produced since ancient times, resulting from an alcoholic fermentation of diluted honey by yeasts. When it is produced in a traditional manner, mead producers can encounter several problems related to a lack of es-sential nutrients, such as available nitrogen. Thus, the aim of this study was to evaluate the effect of nitrogen addition to honey-must on the fermentation performance of two Saccharomyces cerevisiae wine yeasts, QA23 and ICV D47, as well as on the mead composition and production of volatile aroma compounds. A portion of honey-must was supplemented with diammonium phosphate (DAP) to achieve the nitrogen concentration required by yeast to complete alcoholic fermentation. The supplementation with DAP reduced the fermentation length to around 7 days, but not all sugars were fully consumed, suggesting that other factors could be interfering with yeast growth. For both yeasts the specic growth rate and nal bio-mass were higher in musts supplemented with DAP. Mead nal composition was similar under the two experimental condi-tions. Analysis of the volatile prole revealed that the concentrations of the volatile fatty acids and volatile phenols were higher in meads supplemented with DAP. The concentrations of ethyl hexanoate, ethyl octanoate and isoamyl acetate were above their perception threshold and were higher in meads supplemented with DAP, which could contribute to the enhance-ment of the fruity character. This study could be useful for the optimization of mead production and quality improvement.The research presented in this paper was partially funded by the Fundacao para a Ciencia e Tecnologia (FCT) (project PTDC/AGR-ALI/68284/2006). A.P.P. is a recipient of a PhD grant from the FCT (SFRH/BD/45820/2008)

Патон Борис Євгенович

Патон Борис Євгенович — видатний вітчизняний учений, всесвітньо відомий спеціаліст в галузі зварювання, металознавства, металургії, спорудження відповідальних інженерних конструкцій, автор багатьох фундаментальних ре зультатів і створених на їх основі нових технологій і відповідного обладнання. У 1951 р. його обрано членом-кореспондентом, в 1958 р. — дійсним членом (академіком) Академії наук УРСР, з 1962 р. він — її президент

Influence of fining agents on the sensorial characteristics and volatile composition of mead

Mead, one of the oldest fermented drinks, is derived from the fermentation of diluted honey by yeasts. In the context of wine production, several procedures are applied to stabilize the beverage and to improve its organoleptic properties. This study aims to evaluate the impact of adding fining agents on the production of mead. In general, the best results were obtained for the samples containing just one fining agent instead of two combined. However, the best performance was obtained for the combined fining agents (bentonite + gelatine + egg albumin). Tannins decreased significantly the content of volatile compounds. On the other hand, silica appears to be the best fining agent, resulting in the lowest loss of volatile compounds. Thirty-six volatile compounds were determined by gas chromatographflame ionization detector and gas chromatographymass spectrometry, including alcohols (42.5%), carbonyl compounds (40.4%), acetates (14.4%) and esters (1.8%). Eleven volatile compounds had odour activity values >1, representing those with a major impact on the aroma of mead. Significant differences (p 0.05) were observed for remaining compounds.A. Pascoal would like to thank Fundação para a Ciência e Tecnologia (FCT), Programa Operacional Pontencial Humano and European Union for his postdoctoral grant (SFRH/BPD/91380/2012). The authors are grateful to FCT, Portugal and Fundo Europeu de Desenvolvimento Regional (FEDER) under Programme PT2020 for financial support to Centro de Investigação de Montanha (CIMO) (UID/AGR/00690/2013). This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the European Regional Development Fund (ERDF) through the COMPETE2020 – Programa Operacional Competitividade e Internacionalização.info:eu-repo/semantics/publishedVersio

Early leaf removal impact on volatile composition of Tempranillo wines

Early defoliation is a very innovative technique in viticulture used for yield management. The effects of early leaf removal performed manually and mechanically at two different phenological stages, pre-bloom and fruit set, on the volatile composition of Tempranillo (Vitis vinifera L.) wines were studied. Volatiles were identified and quantified by gas chromatography Early leaf removal only modified the total concentrations of C6 compounds and acetates, whereas total alcohols, esters, volatile acids and terpenes remained generally unaffected. Early defoliation induced a significant reduction in C6 compounds and increased the concentrations of acetates in Tempranillo wines. An effect of timing (pre-bloom vs fruit set) alone was observed for all acetates analysed. Regarding the method of defoliation (manual vs mechanical), significant differences in some ethyl ester (ethyl-2-methylbutyrate and ethyl octanoate) and volatile acid concentrations were observed among treatments. Ethyl octanoate, 2-phenylethyl acetate, 3-methylbutyl acetate and hexanoic acid, with OAV (odour activity value) > 1 and mainly fruity and floral odour descriptors, showed higher levels after early defoliation treatments compared with non-defoliated vines. Principal component analysis illustrated the difference in wines from defoliated and non-defoliated treatments based on their volatile composition. It can be concluded that early leaf removal significantly modified the wine aroma compounds, increasing or decreasing several of these compounds.We thank the Agencia de Desarrollo Economico de La Rioja (ADER) and the Ministerio de Ciencia e Innovacion for their financial support (ADER-2006-I-ID-00157 and AGL2007-60378 respectively). We would also like to thank the Agrupacion de Bodegas Centenarias y Tradicionales de Rioja (ABC) and New Holland for their assistance and help. Dr Vilanova is grateful to the 'Isidro Parga Pondal' programme financed by the Xunta de Galicia (Spain)

Production of white wine by Saccharomyces cerevisiae immobilized on grape pomace

White wine was produced with Saccharomyces cerevisiae cells immobilized on grape pomace, by natural adsorption. The support, the main solid waste from the wine industry, consisted of the skins, seeds and stems. Immobilization was tested using different media, namely complex culture medium, raw grape must and diluted grape must. Grape pomace was revealed to be an appropriate support for yeast cell immobilization. Moreover, grape must was shown to be the most suitable medium as immobilized cells became adapted to the conditions in the subsequent alcoholic fermentation in the wine-making process. The wines produced, either with immobilized cells or with free cells, were subjected to chemical analysis by HPLC (ethanol,glycerol, sugars and organic acids) and by gas chromatography (major and minor volatile compounds); additionally, colour (CIELab) and sensory analysis were performed. The use of immobilized systems to conduct alcoholic fermentation in white wine production proved to be a more rapid and a more efficient process, especially when large amounts of SO2 were present in the must. Furthermore, the final wines obtained with immobilized cells demonstrated improved sensory properties related to the larger amounts of ethanol and volatile compounds produced. The more intense colour of these wines could be a drawback, which could be hindered by the reutilization of the biocatalyst in successive fermentations.Zlatina Genisheva gratefully acknowledges FCT (contract/grant number: SFRH/BD/48186/2009) for financial support of this work. The authors would like to thank Divisao de Vitivinicultura Direccao Regional de Agricultura e Pescas do Norte for providing the grape pomace for yeast immobilization and the must to conduct alcoholic fermentations. The authors thank also Professor Joao Linhares for help in computing the CIELab coordinates

Oenological characterisation of indigenous strains of S. cerevisiae isolated in a biodynamic winery in the Cortona DOC area

Genotypic and technological characterisation of the S. cerevisiae population isolated in a biodynamic winery in the Cortona DOC area was performed to gain better knowledge of the variables that influence winemaking. The oenological performance of 11 S. cerevisiae strains was evaluated with physiological tests; strain typing was performed through analysis of interdelta sequences and 26S rDNA sequencing. The analysis revealed a remarkable variability in terms of S. cerevisiae strains, despite the homogeneity of wine features, underlining the high levels of biodiversity characterising biodynamic agriculture. Some strains were found in wines of different vintages, suggesting the presence of an established microbiota in the winery. Oenological tests demonstrated that while some yeasts provided reliable oenological performance, other strains were not able to accomplish prompt and effective alcoholic fermentation, or were characterised by spoilage characteristics, such as excessive production of volatile phenols or acetic acid. Indigenous strains of S. cerevisiae could be a useful instrument for reliable winemaking without altering the native microbiota of each oenological environment. However, characterisation of their oenological suitability, and the application of practices able to drive the evolution of microbiota, must be employed to reduce the risk of wine spoilage