The paper’s aim is to emphasize the variety of the yeasts populations which are present in the musts from inland and Tokaj areas. The study is based on the alcoholic fermentation on the four strains ...which were selected for this purpose, the isolation of the specific yeasts and the quantification of the obtained results through in the data base. From the fermentative dynamics’ point of view, the differences occur depending on the growing environment and on the strain types which were considered.The minerals play an important role in increasing the biotechnological properties of the wine yeasts Saccharomyces bayanus, Saccharomyces ellipsoideus regarding the fermentative activity and multiplication speed.
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•High-pressure CO2 is applied to hydrothermal pretreatment of peanut shell.•It dramatically decomposes hemicellulose of pretreated substrate to as low as 1.8%.•It significantly ...increases the pore area and porosity of pretreated substrate.•Pretreated substrate yields 81% glucose leading to 12% increase in bioethanol.•Mechanism behind the dual effect from application of high-pressure CO2 is proposed.
Peanut shells (i.e., an abundant industrial by-product) were subjected to an innovative hydrothermal pretreatment approach using high-pressure CO2 to enhance their enzymatic hydrolysis conversion into glucose. This pretreatment led to a reduction in hemicellulose content in the pretreated peanut shells from 12.4% to as low as 1.8%, which facilitated subsequent conversion into glucose by enzymatic hydrolysis. This pretreatment approach was assessed within a 170–200 °C temperature range and a 20–60 bar CO2 pressure range, after which the results of these conditions were compared to those of conventional hot water pretreatment. Treatment at 190 °C and a 60-bar CO2 pressure was determined to be optimal, resulting in the highest glucose yield (80.7%) from subsequent enzymatic hydrolysis. Acidic conditions resulting from CO2-derived carbonic acid significantly reduced the hemicellulose content of the peanut shells and weakened the interaction between cellulose, hemicellulose, and lignin, improving enzyme accessibility to the cellulose. Furthermore, high-pressure CO2 increased the pore size and porosity of the resulting pretreated peanut shells, improving their enzyme adsorption capacities, as confirmed by cellulase adsorption and mercury intrusion porosimetry tests. The dual effect from high-pressure CO2 led to significant hemicellulose reduction and improved adsorption of enzymes on the cellulose, which in turn increased glucose yield from the subsequent enzymatic hydrolysis of pretreated peanut shells. Alcoholic fermentation of the hydrolyzed glucose resulted in a 12.4% increase in bio-ethanol production compared to a glucose control, thus highlighting the potential of pre-treated peanut shells as a glucose precursor used in biofuel industry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
La investigación se enfocó en valorar la influencia de fermentadores en cajones de madera: Guayacán (Tabebuia Chrysantha), Laurel (Laurus nobilis), y Caña (Guadua angustifolia) sobre la calidad ...fisicoquímicas de las almendras de cacao (Theobroma cacao L.). Se aplicó un diseño AXB con arreglo factorial (2x3) y se determinó el porcentaje de fermentación en los tres tipos de cajas visualizando el 60 % mínimo de almendras bien fermentadas, granos violetas 21 %, granos pizarrosos superó el 12 %, lograr las mejores características organolépticas en el grano de cacao resultante, implica un adecuado tratamiento, mejores prácticas aplicadas y la incorporación de un tipo de fermentador que garantice el éxito del proceso.
Cabe señalar que el primer proceso se ve afectado por varios factores tales como: tipo de madera a utilizar para la construcción de los cajones, dimensiones de estos, el tamaño de los orificios que permiten la evacuación del mucilago y las remociones que se le dé a la masa durante el proceso. El proceso fermentativo se convierte en el principal proceso del beneficio pues los cambios que se originan son fundamentales para que aparezcan los agentes precursores del aroma y sabor típicos del cacao de calidad. Es por eso por lo que se ha utilizado un modelo matemático para poder determinar datos importantes en la fermentación alcohólica que se realiza en las cajas. Dicho de esta manera se aplica una modelación matemática para la fermentación de Cacao (Theobroma cacao L.), para la cinética correspondiente, el comportamiento de la biomasa con el consumo de sustrato y el comportamiento del sustrato y Crecimiento microbiano por medio de los modelos matemáticos de Monod y de Andrews y Levenspiel.
Palabras clave: Crecimiento Microbiano, Fermentación Alcohólica, Mucilago, Madera, Matemáticas Modelos.
The wine yeasts have multiple and important applications in the industry, aiming to obtain pure cultures and the selection of those strains which, according to the lab investigations, present ...superior bio-technological properties. In this study we monitored three types of Saccharomyces bayanus yeast strains, isolated from indigenous grapes varieties, Apold Iordana, Italian Blaj Riesling and Royal Feteasca from Jidvei area, which are present in the collection of the Biotechnologies and Microbiology Research Center of SAIAPM University. The yeast strains were subject to alcoholic fermentation in malt must at different temperatures, in the presence of alcohol, sugar and SO2 in various concentrations. The obtained results led to selecting of those strains which had best results regarding the alcoholic tolerance, osmo-tolerance, fermentation speed under stress conditions and resistance to SO2. These results can have practical applications in using the indigenous strains, isolated from grapes which are from inside the country, so that we preserve the local specificity, and reduce imports regarding this area.
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Higher alcohols are important flavor substance in alcoholic beverages. The content of α-amino nitrogen (α-AN) in the fermentation system affects the formation of higher alcohols by Saccharomyces ...cerevisiae. In this study, the effect of α-AN concentration on the higher alcohol productivity of yeast was explored, and the mechanism of this effect was investigated through metabolite and transcription sequence analyses. We screened 12 most likely genes and constructed the recombinant strain to evaluate the effect of each gene on high alcohol formation. Results showed that the AGP1, GDH1, and THR6 genes were important regulators of higher alcohol metabolism in S. cerevisiae. This study provided knowledge about the metabolic pathways of higher alcohols and gave an important reference for the breeding of S. cerevisiae with low-yield higher alcohols to deal with the fermentation system with different α-AN concentrations in the brewing industry.
•Lower or higher α-amino nitrogen content leads to the production of higher alcohols.•α-Amino nitrogen influences the metabolic networks of higher alcohols differently.•Several metabolic pathways are the key factors affecting higher alcohol production.•AGP1, GDH1, and THR6 genes are important regulators of higher alcohol metabolism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The existence and function of unculturable microorganisms are necessary to explain patterns of microbial diversity and investigate the assembly and succession of the complex microbial community. ...Chinese traditional alcoholic fermentation starter contains a complex microbial community harboring unculturable species that control the microbial diversity and have distinct functions. In this study, we revealed the presence, functions, and interactions of these unculturable species. Results of microbial diversity revealed by culture-dependent and metagenomic sequencing methods identified unculturable species and the potential functional species. Unculturable
and
sp. had a strong ability to form biofilms and co-existed as a mixed-species biofilm in the starter community. Using a hydrolase activity assay and fortified fermentation, we determined that the function of
and
sp. to produce ethanol and flavor compounds. Widespread microbial interactions were identified among the biofilm isolates.
was the main component of the biofilm and dominated the metabolic activities in the mixed-species biofilm. The environmental adaptability and biomass of
sp. were increased through its interaction with
. The mixed biofilm of
and
sp. also provides a tool for correlating microbial diversity patterns with their function in the alcoholic fermentation starter, and may provide a new understanding of fermentation mechanisms. Formation of a mixed-species biofilm represents a strategy for unculturable species to survive in competition with other microbes in a complex community.
Red dragon fruit is a popular tropical fruit that has been highly prized for its health benefits partially attributed to the high antioxidant content. Nevertheless, besides being consumed fresh, ...further processing into juice or other products is scarce due to its high pectin content that presents a challenge in industrial processing. In this study, we evaluated the effects of pectinase pre-treatment on red dragon fruit wine fermented with Torulaspora delbrueckii. Pectinase enzyme (Pectinex® Ultra SP-L, added at 0.1% v/v) was applied after pasteurization of juice followed by fermentation with T. delbrueckii at 20 °C for 14 days. Pectinase pre-treatment did not affect the yeast growth, nor the production of ethanol (8% v/v) and glycerol (6 g/L), but significantly increased juice/wine yield by 16% v/v. In addition, pectinase treated samples after fermentation remained significantly higher levels of residual nitrogen containing compounds, indicating unfavorable fermentation conditions and impaired metabolism of the yeast. Moreover, fermented pectinase treated samples possessed the aroma compound profiles with enriched esters and terpenes but decreased higher alcohols. Furthermore, pectinase treatment increased the total phenolic content, but decreased betacyanins content and color intensity compared to control sample. The findings would have practical significance for diversifying products from red dragon fruit.
•Pectinase was used in red dragon fruit wine (RDFW) fermented with Torulaspora delbrueckii.•Pectinase treatment increased wine yield by 16% v/v.•Pectinase inhibited the nitrogen consumption of T. delbrueckii.•Pectinase treatment enhanced the volatile flavor profiles.•The antioxidant property of RDFW with pectinase treatment is higher than control samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Carotenoids are isoprenoids compounds widely distributed in foods. A difference of carotenoids relative to other food bioactives is that some can be converted into compounds exhibiting vitamin A ...activity, which is essential for humans. Besides, they are more versatile as they are also natural pigments, antioxidants and can be involved in health-promoting actions. Lately, they are also attracting interest in relation to skin beauty. Their importance for different industry sector (foods, feeds, pharmaceutical, cosmetics) is therefore indisputable. Carotenoids can be obtained by different approaches including extraction from appropriate sources or synthesis.
Due to their advantages (easiness for the optimization of conditions to obtain higher yields, versatility, etc.) fermentative processes have been long studied and even applied at industrial scale for their production. On the other hand, food fermentation is an ancient approach that usually results in products with new characteristics, enhanced quality and/or better preservation. However, the impact of such processes on the carotenoids present in the foods and their bioavailability are not well understood yet.
In this work, approaches used to obtain carotenoids by fermentation are reviewed as well as the impact of food fermentation on these compounds. Some research needs are also pinpointed, including further studies on the effect of food fermentations on the potential bioavailability of carotenoids, the production of carotenoids of commercial interest other than β-carotene, lycopene or astaxanthin or that of carotenoid cleavage derivatives.
•Alcoholic or lactic acid fermentations do not cause important losses of carotenoids.•Increased carotenoids after fermentation due to facilitated extractability.•Fermentations can lead to increased aroma compounds from carotenoids.•β-carotene or lycopene are produced from fermentation (B. trispora).•Fermentation can produce “uncommon” “unusual” carotenoids such as torulene or torularhodin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Yeast lipid composition depends on the species and on environmental conditions.•Lipid metabolism and transport in yeasts are reviewed.•Lipids play various roles in yeasts, including ...stress resistance.•In winemaking, lipid content of yeast membranes impacts survival and fermentation performance.•Grape juice lipid content affects yeast metabolism and ultimately wine composition.
Lipids are valuable compounds present in all living organisms, which display an array of functions related to compartmentalization, energy storage and enzyme activation. Furthermore, these compounds are an integral part of the plasma membrane which is responsible for maintaining structure, facilitating the transport of solutes in and out of the cell and cellular signalling necessary for cell survival. The lipid composition of the yeast Saccharomyces cerevisiae has been extensively investigated and the impact of lipids on S. cerevisiae cellular functions during wine alcoholic fermentation is well documented. Although other yeast species are currently used in various industries and are receiving increasing attention in winemaking, little is known about their lipid metabolism. This review article provides an extensive and critical evaluation of our knowledge on the biosynthesis, accumulation, metabolism and regulation of fatty acids and sterols in yeasts. The implications of the yeast lipid content on stress resistance as well as performance during alcoholic fermentation are discussed and a particular emphasis is given on non-Saccharomyces yeasts. Understanding lipid requirements and metabolism in non-Saccharomyces yeasts may lead to a better management of these yeast to enhance their contributions to wine properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In oenology, the utilization of mixed starter cultures composed by Saccharomyces and non-Saccharomyces yeasts is an approach of growing importance for winemakers in order to enhance sensory quality ...and complexity of the final product without compromising the general quality and safety of the oenological products. In fact, several non-Saccharomyces yeasts are already commercialized as oenological starter cultures to be used in combination with Saccharomyces cerevisiae, while several others are the subject of various studies to evaluate their application. Our aim, in this study was to assess, for the first time, the oenological potential of H. uvarum in mixed cultures (co-inoculation) and sequential inoculation with S. cerevisiae for industrial wine production. Three previously characterized H. uvarum strains were separately used as multi-starter together with an autochthonous S. cerevisiae starter culture in lab-scale micro-vinification trials. On the basis of microbial development, fermentation kinetics and secondary compounds formation, the strain H. uvarum ITEM8795 was further selected and it was co- and sequentially inoculated, jointly with the S. cerevisiae starter, in a pilot scale wine production. The fermentation course and the quality of final product indicated that the co-inoculation was the better performing modality of inoculum. The above results were finally validated by performing an industrial scale vinification The mixed starter was able to successfully dominate the different stages of the fermentation process and the H. uvarum strain ITEM8795 contributed to increasing the wine organoleptic quality and to simultaneously reduce the volatile acidity. At the best of our knowledge, the present report is the first study regarding the utilization of a selected H. uvarum strain in multi-starter inoculation with S. cerevisiae for the industrial production of a wine. In addition, we demonstrated, at an industrial scale, the importance of non-Saccharomyces in the design of tailored starter cultures for typical wines.
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