Search results for "fermentation"
showing 10 items of 746 documents
Attachment of yeast to modified stainless steel wire spheres, growth of cells and ethanol production
1999
Abstract The immobilization of yeast Saccharomyces cerevisiae, their growth and ethanol production were investigated using untreated and modified stainless steel wire spheres (WS) as carriers. The carrier surface was modified by oxidation, by treatment with titanium (IV) chloride (TiCl4) or by γ-aminopropyltrietoxysilane (AS) in an attempt to raise the efficiency of the immobilization of the yeast cells. The influence of the cell fixation method on culture growth and ethanol synthesis was investigated. The immobilization of cells to carrier surface was checked by scanning electron microscopy (SEM). More closely attachment of yeast cells was seen on the aminated wire surface. It was establis…
ANALISIS KADAR BIOETANOL HASIL FERMENTASI DARI NIRA NIPAH (Nypa fruticans wurmb) ASAL PAPUA
2019
This study aims to analyze the ethanol content in fermented palm juice.This research includes the preparation of raw materials, fermentation, distillation and distillation products analyzed by gas chromatography method. Fermentation is carried out for 2, 5, 7 days, the highest level of bioethanol produced is then selected for distillation. Levels the highest fermentation process is on the 5th day with a level of 18%. Got results the final distillation is 117 mL with a level of 94% of the initial volume of 4.2 L fermentation based on measurements using an alcoholmeter while the analysis by gas chromatography yielded 93.9% levels. The density of bioethanol is 0.8232 gr / mL. The results of th…
La fermentation en milieu solide : une innovation de rupture à (re)découvrir
2015
Référence : 201511123537; National audience; Le principal challenge de l’industrie des biotechnologies est lié au développement d’un procédé qui est à la fois économique et efficace en utilisant des matières premières renouvelables pour délivrer des produits à haute valeur ajoutée. La fermentation en milieu solide (FMS) qui met en œuvre des microorganismes sur des matières premières biologiques est un procédé pouvant répondre à ces problématiques.
Ageing on lees ( sur lies ) and the use of speciality inactive yeasts during wine fermentation
2010
Abstract: The chapter begins by describing the lees and autolysis phenomena: mechanism and released products. It then reviews the influence of ageing ‘ sur lies ’ on the organoleptic and hygienic properties and the stability of white, red and sparkling wines. The chapter includes a description of different yeast preparations mimicking the lees and their use in winemaking.
Temperature Adaptation Markedly Determines Evolution within the Genus Saccharomyces
2011
12 pages, 7 figures, 3 tables
Yeast autolysis in sparkling wine – a review
2006
Sparkling wine produced by the traditional methode champenoise requires a second in-bottle alcoholic fermentation of a base wine, leading to the sparkling wine. This second fermentation is followed by prolonged ageing in contact with yeast cells (lees). The autolysis of yeast occurs during the ageing of sparkling wines. During this process, the yeast releases different compounds that modify the organoleptic properties of the wine. The ageing period is required to give these wines their roundness and characteristic aroma and flavour. Autolysis products also influence the foaming properties of sparkling wine. Yeast autolysis is characterised by the hydrolysis of intracellular biopolymers by y…
Transformation of Ochratoxin A by Microorganisms Isolated from Tempranillo Grapes in Wine Systems
2020
Mycotoxins are toxic metabolites produced by various genera of fungi. Fungi belonging to species of the genera Aspergillus and Penicillium are the main source of ochratoxin A (OTA) in wine. The reduction of OTA in must and wine has been studied using physical, chemical, and biological technologies. In this paper, we report on the capacity of different cultures isolated from Tempranillo winegrapes contaminated with fungus to degrade OTA in tryptic soy broth (TSB) medium at pH 3.5 and 6.5. We studied the interaction between OTA and four isolates during alcoholic fermentation of red wine. This study showed that microorganism isolates reduced the content of OTA in TSB medium and in the wine exp…
Enzyme contribution of non-Saccharomyces yeasts to wine production
2015
The fermentation of grape must to produce wine is a biologically complex process, carried on by yeasts and malolactic bacteria. The yeasts present in spontaneous fermentation may be divided into two groups, the Saccharomyces yeasts, particularly S. cerevisiae, and the non-Saccharomyces yeasts which include members of the genera Rhodotorula, Pichia, Candida, Debaryomyces, Metschtnikowia, Hansenula and Hanseniaspora. S. cerevisiae yeasts are able to convert sugar into ethanol and CO2 via fermentation. They have been used for thousands of years by mankind for the production of fermented beverages and foods, including wine. Their enzymes provide interesting wine organoleptic characteristics. β-…
Indigenous yeast communities in the environment of ‘‘Rovello bianco’’ grape variety and their use in commercial white wine fermentation
2009
The indigenous yeast communities associated with several vineyard habitats were analysed. Wild yeasts were isolated, differentiated at strain level and identified. A phylogenetic tree based on partial 26S rRNA genes was constructed. The strains were characterized and the indigenous Saccharomyces cerevisiae GR1 was then used to carry out a vinification process and compared with a commercial yeast. Wines obtained were subjected to chemical and sensory analysis. The comparison between the two products highlighted differences due to the fer- menting strains employed. The vineyard environment was found to strongly influence the composition of yeast communities, thus, confirming the theory of ‘te…
Base Wine and Traditional Sparkling Wine Making Using Torulaspora delbrueckii Killer Yeasts
2020
The killer strains of Torulaspora delbrueckii can be used to improve the dominance of this yeast during must fermentation. The present work analyzes its usefulness for traditional sparkling wine making (base wine and cava). T. delbrueckii killer strain dominated base wine fermentation better than non-killer strains and produced dried wines. The foam ability of T. delbrueckii base wines was very low compared to that of Saccharomyces cerevisiae. Significant positive correlations of foam parameters were found with the amounts of C4-C16 ethyl esters and proteins, and negative correlations with some antifoam alcohols. The organoleptic quality of T. delbrueckii base wines was considered inap…