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Emilia Garciamoruno - One of the best experts on this subject based on the ideXlab platform.
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short term response of different saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in Grape Must rt qpcr study and metabolite analysis
Food Microbiology, 2015Co-Authors: Olta Noti, Enrico Vaudano, Enrica Pessione, Emilia GarciamorunoAbstract:During the winemaking process, glycerol synthesis represents the first adaption response of Saccharomyces cerevisiae to osmotic stress after inoculation in Grape Must. We have implemented an RT-qPCR (Reverse Transcription-quantitative PCR) methodology with a preventive evaluation of candidate reference genes, to study six target genes related to glycerol synthesis (GPD1, GPD2, GPP2 and GPP1) and flux (STL1 and FPS1), and three ALD genes coding for aldehyde dehydrogenase involved in redox equilibrium via acetate production. The mRNA level in three strains, characterized by different metabolite production, was monitored in the first 120 min from inoculation into natural Grape Must. Expression analysis shows a transient response of genes GPD1, GPD2, GPP2, GPP1 and STL1 with differences among strains in term of mRNA abundance, while FPS1 was expressed constitutively. The transient response and different expression intensity among strains, in relation to the intracellular glycerol accumulation pattern, prove the negative feedback control via the HOG (High Osmolarity Glycerol) signalling pathway in S. cerevisiae wine strains under winery conditions. Among the ALD genes, only ALD6 was moderately induced in the hyperosmotic environment but not in all strains tested, while ALD3 and ALD4 were drastically glucose repressed. The intensity of transcription of ALD6 and ALD3 seems to be related to different acetate production found among the strains.
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short term response of different saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in Grape Must rt qpcr study and metabolite analysis
Food Microbiology, 2015Co-Authors: Olta Noti, Enrico Vaudano, Enrica Pessione, Emilia GarciamorunoAbstract:During the winemaking process, glycerol synthesis represents the first adaption response of Saccharomyces cerevisiae to osmotic stress after inoculation in Grape Must. We have implemented an RT-qPCR (Reverse Transcription-quantitative PCR) methodology with a preventive evaluation of candidate reference genes, to study six target genes related to glycerol synthesis (GPD1, GPD2, GPP2 and GPP1) and flux (STL1 and FPS1), and three ALD genes coding for aldehyde dehydrogenase involved in redox equilibrium via acetate production. The mRNA level in three strains, characterized by different metabolite production, was monitored in the first 120 min from inoculation into natural Grape Must. Expression analysis shows a transient response of genes GPD1, GPD2, GPP2, GPP1 and STL1 with differences among strains in term of mRNA abundance, while FPS1 was expressed constitutively. The transient response and different expression intensity among strains, in relation to the intracellular glycerol accumulation pattern, prove the negative feedback control via the HOG (High Osmolarity Glycerol) signalling pathway in S. cerevisiae wine strains under winery conditions. Among the ALD genes, only ALD6 was moderately induced in the hyperosmotic environment but not in all strains tested, while ALD3 and ALD4 were drastically glucose repressed. The intensity of transcription of ALD6 and ALD3 seems to be related to different acetate production found among the strains.
Athanasios A Koutinas - One of the best experts on this subject based on the ideXlab platform.
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Volatiles Formation from Grape Must Fermentation Using a Cryophilic and Thermotolerant Yeast
Applied Biochemistry and Biotechnology, 2012Co-Authors: Nikolaos Kopsahelis, Loulouda Bosnea, Maria Kanellaki, Athanasios A KoutinasAbstract:Grape Must fermentation performance and volatiles formation by simultaneously cryophilic and thermotolerant yeast (strain AXAZ-1), isolated from Grapes in Greece, was evaluated in a wide temperature range (5–40°C). Yeast strain was immobilized on brewer’s spent grains (BSG) and the formed biocatalyst was introduced into a Multi-Stage Fixed Bed Tower (MFBT) bioreactor. Almost complete sugar utilization from the aforementioned biocatalyst was observed in a wide temperature spectrum, ranging from 5 °C to 37 °C, while at 40 °C residual sugar was up to 29 g/l. Time to complete fermentation with the immobilized yeast ranged from 290 h at 5 °C and 120 h at 40 °C to 25 h at 33 °C. The daily ethanol productivity reached maximum (88.6 g/l) and minimum (5.6 g/l) levels at 33 °C and 5 °C, respectively. The aroma-related compounds’ profiles of immobilized cells at different fermentation temperatures were evaluated by using solid phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS). Must fermentation resulted in a high-quality fermentation product due to the low concentrations of higher and amyl alcohols at all temperatures tested. AXAZ-1 is a very promising strain for quality wine production, as it is capable of performing fermentations of high ethanol concentration and productivities in both low and high temperatures.
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scale up of extremely low temperature fermentations of Grape Must by wheat supported yeast cells
Bioresource Technology, 2010Co-Authors: Panagiotis Kandylis, Chryssoula Drouza, Argyro Bekatorou, Athanasios A KoutinasAbstract:A new biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on whole wheat grains. This biocatalyst was used for 30 repeated batch fermentations of glucose and Grape Must at various temperatures. The biocatalyst retained its operational stability for a long period and it was proved capable to produce dry wines of fine clarity even at extremely low temperatures (5 degrees C). After the completion of these fermentations the new biocatalyst was used in a scale-up system of 80 L for wine making at ambient (20 degrees C) and extremely low temperatures (2 degrees C). The scale-up process did not affect the fermentative ability of biocatalyst, even at low temperatures, while the produced wines had almost the same improved aromatic profile compare to free cells as revealed by GC and GC-MS analyses. More specifically the results showed that both systems with immobilized cells (laboratory scale and 80 L bioreactor) increased the formation of esters and produced wines with improved aromatic profile compared to those with free cells. Finally an increase in the percentages of total esters and a decrease in those of higher alcohols was observed in lower fermentation temperatures.
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extremely low temperature fermentations of Grape Must by potato supported yeast strain axaz 1 a contribution is performed for catalysis of alcoholic fermentation
Journal of Agricultural and Food Chemistry, 2008Co-Authors: Panagiotis Kandylis, Athanasios A KoutinasAbstract:This investigation announces the use of potato pieces as a suitable support for cell immobilization resulting in extremely low temperature wine making. The results showed an increase of the total esters by immobilized cells and reduction of higher alcohols. Likewise, percentages of total esters on total volatiles were increased by the drop in temperature, while percentages of higher alcohols were reduced in wines. Kinetics experiments at different temperatures allowed the calculation of activation energy (Ea) and showed reduction in the case of immobilized cells as compared with free cells. These results may lead to the conclusion that the increased productivities that are obtained by immobilized cells, can be attributed to the catalytic activity by the support to enzymes, which are involved in the process. Biocatalysts were prepared by immobilization of Saccharomyces cerevisiae, strain AXAZ-1, on whole potatoes and potato pieces, and their efficiency for alcoholic repeated batch fermentations of glucose and Grape Must in the range 2-30 degrees C was examined. To study the operational stability of biocatalyst, 35 repeated batch fermentations of Grape Must were performed without any significant reduction of the fermentation activity. Wines were analyzed for volatile byproducts determination by GC and GC-MS.
Raffaella Di Cagno - One of the best experts on this subject based on the ideXlab platform.
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yogurt like beverages made of a mixture of cereals soy and Grape Must microbiology texture nutritional and sensory properties
International Journal of Food Microbiology, 2012Co-Authors: Rossana Coda, Marco Gobbetti, Alessia Lanera, Antonio Trani, Raffaella Di CagnoAbstract:Cereal (rice, barley, emmer and oat) and soy flours and concentrated red Grape Must were used for making vegetable yogurt-like beverages (VYLB). Two selected strains of Lactobacillus plantarum were used for lactic acid fermentation, according to a process which included the flour gelatinization. All VLYB had values of pH lower than 4.0 and both selected starters remained viable at ca. 8.4 log cfu/g throughout storage. All VLYB showed high values of apparent viscosity and water holding capacity. During fermentation, lactic acid bacteria consumed glucose, fructose, and malic acid, which was supplied with Grape Must. Compared to control vegetable yogurt-like beverages (CVYLB), without bacterial inoculum, an increase of total free amino acids (FAA) was found during fermentation and storage. Also the concentration of polyphenolic compounds and ascorbic acid (ASC) was higher in VLYB compared to CVYLB. This was reflected on the antioxidant activity. As determined by Solid Phase Micro-Extraction/Gas-Chromatography/Mass-Spectrometry analysis, several volatile compounds were identified. Beverages made with the mixture of rice and barley or emmer flours seemed to possess the best combination textural, nutritional and sensory properties.
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synthesis of γ aminobutyric acid gaba by lactobacillus plantarum dsm19463 functional Grape Must beverage and dermatological applications
Applied Microbiology and Biotechnology, 2010Co-Authors: Raffaella Di Cagno, Francesco Mazzacane, Marisa Meloni, Barbara De Servi, Giammaria Giuliani, Maria De Angelis, Carlo Giuseppe Rizzello, Marco GobbettiAbstract:Agriculture surplus were used as substrates to synthesize γ-aminobutyric acid (GABA) by Lactobacillus plantarum DSM19463 for the manufacture of a functional beverage or as a novel application for dermatological purposes. Dilution of the Grape Must to 1 or 4% (w/v) of total carbohydrates favored higher cell yield and synthesis of GABA with respect to whey milk. Optimal conditions for synthesizing GABA in Grape Must were: initial pH 6.0, initial cell density of Log 7.0 cfu/mL, and addition of 18.4 mM l-glutamate. L. plantarum DSM19463 synthesized 4.83 mM of GABA during fermentation at 30°C for 72 h. The fermented Grape Must also contain various levels of niacin, free minerals, and polyphenols, and Log 10.0 cfu/g of viable cells of L. plantarum DSM19463. Freeze dried preparation of Grape Must was applied to the SkinEthic® Reconstructed Human Epidermis or multi-layer human skin model (FT-skin tissue). The effect on transcriptional regulation of human beta-defensin-2 (HBD-2), hyaluronan synthase (HAS1), filaggrin (FGR), and involucrin genes was assayed through RT-PCR. Compared to GABA used as pure chemical compound, the up-regulation HBD-2 was similar while the effect on the expression of HAS1 and FGR genes was higher.
Olta Noti - One of the best experts on this subject based on the ideXlab platform.
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short term response of different saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in Grape Must rt qpcr study and metabolite analysis
Food Microbiology, 2015Co-Authors: Olta Noti, Enrico Vaudano, Enrica Pessione, Emilia GarciamorunoAbstract:During the winemaking process, glycerol synthesis represents the first adaption response of Saccharomyces cerevisiae to osmotic stress after inoculation in Grape Must. We have implemented an RT-qPCR (Reverse Transcription-quantitative PCR) methodology with a preventive evaluation of candidate reference genes, to study six target genes related to glycerol synthesis (GPD1, GPD2, GPP2 and GPP1) and flux (STL1 and FPS1), and three ALD genes coding for aldehyde dehydrogenase involved in redox equilibrium via acetate production. The mRNA level in three strains, characterized by different metabolite production, was monitored in the first 120 min from inoculation into natural Grape Must. Expression analysis shows a transient response of genes GPD1, GPD2, GPP2, GPP1 and STL1 with differences among strains in term of mRNA abundance, while FPS1 was expressed constitutively. The transient response and different expression intensity among strains, in relation to the intracellular glycerol accumulation pattern, prove the negative feedback control via the HOG (High Osmolarity Glycerol) signalling pathway in S. cerevisiae wine strains under winery conditions. Among the ALD genes, only ALD6 was moderately induced in the hyperosmotic environment but not in all strains tested, while ALD3 and ALD4 were drastically glucose repressed. The intensity of transcription of ALD6 and ALD3 seems to be related to different acetate production found among the strains.
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short term response of different saccharomyces cerevisiae strains to hyperosmotic stress caused by inoculation in Grape Must rt qpcr study and metabolite analysis
Food Microbiology, 2015Co-Authors: Olta Noti, Enrico Vaudano, Enrica Pessione, Emilia GarciamorunoAbstract:During the winemaking process, glycerol synthesis represents the first adaption response of Saccharomyces cerevisiae to osmotic stress after inoculation in Grape Must. We have implemented an RT-qPCR (Reverse Transcription-quantitative PCR) methodology with a preventive evaluation of candidate reference genes, to study six target genes related to glycerol synthesis (GPD1, GPD2, GPP2 and GPP1) and flux (STL1 and FPS1), and three ALD genes coding for aldehyde dehydrogenase involved in redox equilibrium via acetate production. The mRNA level in three strains, characterized by different metabolite production, was monitored in the first 120 min from inoculation into natural Grape Must. Expression analysis shows a transient response of genes GPD1, GPD2, GPP2, GPP1 and STL1 with differences among strains in term of mRNA abundance, while FPS1 was expressed constitutively. The transient response and different expression intensity among strains, in relation to the intracellular glycerol accumulation pattern, prove the negative feedback control via the HOG (High Osmolarity Glycerol) signalling pathway in S. cerevisiae wine strains under winery conditions. Among the ALD genes, only ALD6 was moderately induced in the hyperosmotic environment but not in all strains tested, while ALD3 and ALD4 were drastically glucose repressed. The intensity of transcription of ALD6 and ALD3 seems to be related to different acetate production found among the strains.
Ulrich Fischer - One of the best experts on this subject based on the ideXlab platform.
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uv c treatment of Grape Must microbial inactivation toxicological considerations and influence on chemical and sensory properties of white wine
Innovative Food Science and Emerging Technologies, 2019Co-Authors: Kathrin Diesler, Patricia Golombek, Dominik Durner, Lisa Kromm, Maren Scharfenbergerschmeer, Hansgeorg Schmarr, Mario Stahl, Karlis Briviba, Ulrich FischerAbstract:UV-C was investigated to inactivate microorganisms in Grape Must. The aim was to evaluate the effect of UV-C on wine-related yeasts under winery conditions, to investigate the toxicological potential and to analyze the effects on chemical and sensory wine properties. Metschnikowia pulcherrima showed the highest UV-C tolerance, Saccharomyces cerevisiae the lowest. With an initial cell count of 106 cfu/mL, M. pulcherrima required a UV-C dose of >1.2 kJ/L, S. cerevisiae <0.8 kJ/L for inactivation. Inactivation efficacy decreased with higher Must turbidity (26.7–144.5 NTU), optical density and degree of microbial load (104–108 cfu/mL) suggesting a shadowing effect of individual microbes. UV-C treatment did not impact mutagenicity as tested by the Ames test. A decrease in dissolved oxygen and caftaric acid content indicated oxidative reactions. UV-C induced color bleaching (ΔE: 0–13) was also observed indicating a degradation of colored pigments. GC × GC–MS analysis revealed a decrease of β-damascenone and linalool content in wines made from UV-C treated Must. Descriptive analysis by a trained sensory panel showed that off-flavors did not occur at doses that were relevant for microbial inactivation (between 1.0 and 3.0 kJ/L).UV-C treatment is a non-thermal processing technique for the preservation of food. In this study, the applicability of UV-C treatment for the inactivation of spoilage yeast in Grape Must was demonstrated in pilot scale. The treatment provided sufficient microbial inactivation without having toxicological impact as examined by the Ames test and without causing off-flavor formation in the wines using relevant doses.
