1,720,975 research outputs found
Cold-active acid pectinolytic system from psychrotolerant Bacillus: Color extraction from red grape skin
Full text linkCold-active enzymes are potentially relevant to food processing and, among them, pectinases belong to the most important enzymes in the fruit juice and wine industry. Bacillus sp. CH15 from grape berries was screened for the production of cold-active acidic pectinolytic enzymes. Taxonomic studies and 16S rDNA analysis revealed that the isolate was closely related to the Bacillus subtilis group. Maximum pectinolytic activity under acidic conditions (pH 5.0) and at low temperature (20°C) was obtained after 24 hr of incubation in medium containing citrus pectin as sole carbon source (0.305 U/mL). Polymethylgalacturonase activity was the predominant pectinase under the given assay conditions, whereas highest levels of pectate lyase activity were found at 60°C. At 5 and 10°C, the enzymatic system maintained 15 and 30% of the maximum activity, respectively. This is the first report on a pectinolytic enzyme system produced by a Bacillus strain and active at 20°C and pH 3.6, conditions similar to those in winemaking. According to classical and CIELab color parameters of short macerations with red grape skins at low temperature, the bacterial pectinolytic system produced a rapid color extraction and the macerates exhibited better chromatic characteristics than those obtained with commercial pectinases or after natural extraction. Total anthocyanin contents of the macerates with Bacillus enzyme system and after natural extraction were significantly different, whereas relative individual pigment quantities did not show any significant difference between the two treatments. In conclusion, Bacillus sp. CH15 could be used as a microbial source of cold-active acidic pectinases in red winemaking.Fil: Martín, María Carolina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatologia - Alimentacion. Area Biologia; ArgentinaFil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatologia - Alimentacion. Area Biologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; Argentin
Classification of the bacteria-Traditional
No full textTraditional bacterial classification deals with useful identification methods based on phenotypic characteristics. These characteristics include morphological, metabolic, physiological, and chemical traits of the cell. Even though the most traditional techniques are not entirely reliable for microbial classification, they should always complement genotypic studies, especially to define the species. Bacterial taxonomy includes three key elements: characterization, classification, and nomenclature of microorganisms, which are the basis of a formal proposal to describe new species. Although there is no official classification system for prokaryotes, the Bergey´s Manual and The Prokaryotes are the most widely accepted classification systems.Fil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Martín, María Carolina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Merín, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; Argentin
Pectinolytic yeasts from viticultural and enological environments: novel finding of Filobasidium capsuligenum producing pectinases
Full text linkIn this study indigenous yeasts associated with wineries, grapes and Malbec fermented must from San Rafael viticulture region (Argentina) were isolated to select pectinolytic strains for their potential use in enology. Pectinolytic yeasts were identified by physiological and molecular methods. Among 78 isolates, only nine were able to produce extracellular pectinases. Six isolated from berry surface were identified as Aureobasidium pullulans and the remaining isolates, recovered
from wineries, belonged to Saccharomyces cerevisiae and Filobasidium capsuligenum species. Pectinase production was evaluated under vinification-related conditions: pH 3.5, 12 and 28 °C. A. pullulans U-12 produced the highest pectinolytic activity at low temperature (1.16 U ml 1), while F. capsuligenum strains showed good activity at 12 and 28 °C (0.77 and 1.15 U ml 1, respectively) being this study the first report on the capacity of this species to produce pectinases. The pectinolytic activity of F. capsuligenum B-13 showed an optimum at pH 4.5 and two peaks at 20 and 50 °C. The enzyme half-life was 2 h at 40 °C and retained 65% of its activity at 40 °C after 1 h of incubation. This pectinolytic system displayed remarkable activity at pH and temperatures found in vinification, suggesting a potential candidate for applying to wine-making.Fil: Merín, María Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mendoza, Lucia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Effect of a cold-active pectinolytic system on colour development of Malbec red wines elaborated at low temperature
Full text linkThe effect of a new cold-active pectinolytic system on colour of Malbec wines was studied under the following winemaking conditions: (i) fermentation at low temperature (20 °C) and (ii) prefermentative cold maceration (PCM) (5 °C–7 days) followed by traditional fermentation (28 °C). The pectinolytic system was mainly composed of polymethylgalacturonase and pectin lyase activities, detected under similar conditions to those in winemaking (pH 3.6–20 °C). The results show that the enzyme system significantly accelerated colour extraction by reducing the maceration time necessary for vinification at low temperature and shortening the PCM stage. Enzyme-treated wines exhibited better chromatic parameters than their controls at devatting and after 6 months of storage. The cold-active enzyme compensated the decrease in colour extraction due to the low maceration temperature, achieving high-quality wines with chromatic characteristics similar to those of traditional wines.Fil: Martín, María Carolina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin
Fermentation Performance of Selected Microorganisms in Malbec Musts under Two Different Wine Making Conditions
Full text linkThis work evaluates the fermentation performance of simultaneous cultures of selected indigenous Saccharomyces cerevisiae mc2, Kloeckera apiculata mF and Oenococcus oeni X2L in Malbec musts. Fermentations (3 l) were carried out at the pilot plant under two conditions: 1-initial pH 5.5, 60.24 mg/l SO2, 26°C) and 2-initial pH 3.8, 125 mg/l SO2, 28°C), using different culture combinations and S.cerevisiae IOC 18-2007 as control. The final wine densities were 0.992-0.997 g/l (10 days). Microorganisms grew in all conditions. Yeasts prevailed, especially S. cerevisiae (108 CFU/ml) while O. oeni reached 107 CFU/ml. Total reducing sugars consumption was >80% and full malate consumption was observed in all musts inoculated with O. oeni. Ethanol formation corresponded to Malbec variety (310-342 mM), while total acidity did not exceed organoleptic quality limit (4.6-6.49 g/l). Glycerol production was ~84.3-95.1 mM. Among tested esters, ethyl acetate/2-phenyl ethyl acetate showed highest concentration. The sensoryanalysis showed the highest scores for visual descriptors (fluency, color intensity and tonality), olfactory intensity, taste descriptors and general harmony. Thus, we propose an inoculation condition using a mixed yeasts-O.oeni culture and an optimal statistical point to improve microbial performance to obtain quality Malbec wines enhancing body and sensorial properties.Fil: Ale, Cesar Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Morata, Vilma Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; ArgentinaFil: Carrión Cervantes, Raúl Orlando. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; ArgentinaFil: Pasteris, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin
Killer yeasts used as starter cultures to modulate the behavior of potential spoilage non-Saccharomyces yeasts during Malbec wine fermentation
Full text linkeast contamination is an important problem that affects wine production worldwide. In the present work, fermentative and biocontrol properties under winemaking conditions of the two killer strains, Saccharomyces cerevisiae Cf8 and Wickerhamomyces anomalus Cf20, were evaluated. S. cerevisiae Cf8 and its combination with W. anomalus Cf20 were able to effectively control the growth of Meyerozyma guilliermondii Cd6 at low SO2 concentrations during Malbec must fermentation. Although the killer strain Cf8 alone exerted lower inhibitory activity, it modulated the growth of the strain Cd6, which positively influenced on wine aroma and complexity without being detrimental to product quality. Malbec wine produced by mixed culture Cf8 and Cd6 was the preferred one by the judges in the sensory analysis. To our knowledge, this is the first study made on red wines produced with indigenous killer yeasts from the Northwest Region of Argentina, as well as the first report of the modulation of potential spoilage yeasts into positive starters using killer yeasts in wine production. These results suggest that killer yeasts could be utilized as starter cultures to produce regional wines using low concentrations of SO2.Fil: Fernandez de Ullivarri, Miguel. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Merín, María Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Mendoza, Lucia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
Some factors affecting the adherence of probiotic Propionibacterium acidipropionici CRL 1198 to intestinal epithelial cells
No full textAdhesion to the intestinal mucosa is generally considered an important property of probiotic microorganisms and has been related to many of their health benefits. This study investigated some factors that could affect or be involved in the adherence of Propionibacterium acidipropionici CRL 1198, a dairy strain with suggested probiotic effects and high adherence in vitro and in vivo to intestinal epithelial cells. In vitro adhesion of propionibacteria was decreased by gastric digestion but not affected by bile and pancreatic enzymes. Adherence was also decreased by pre-treatment of bacterial cells with protease, sodium metaperiodate, and trichloroacetic acid, revealing that different features of the cell surface, like protein factors, carbohydrates, and teichoic acids, are involved in the process. Adherence to intestinal epithelial cells was enhanced by calcium and was dependent on other divalent cations. Adhesion to intestinal mucus was also demonstrated. The results should explain the metabolic effects in the host previously obtained with this strain and support the potential of Propionibacterium for development of new probiotics.Fil: Zarate, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Morata, Vilma Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Perez Chaia, Adriana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Gonzalez, Silvia Nelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin
Characterization of pectinase activity for enology from yeasts occurring in Argentine bonarda grape
Full text linkPectinolytic enzymes are greatly important in winemaking due to their ability to degrade pectic polymers from grape, contributing to enhance process efficiency and wine quality. This study aimed to analyze the occurrence of pectinolytic yeasts during spontaneous fermentation of Argentine Bonarda grape, to select yeasts that produce extracellular pectinases and to characterize their pectinolytic activity under wine-like conditions. Isolated yeasts were grouped using PCR-DGGE and identified by partial sequencing of 26S rRNA gene. Isolates comprised 7 genera, with Aureobasidiumpullulans as the most predominant pectinolytic species, followed by Rhodotorula dairenensis and Cryptococcus saitoi. No pectinolytic activity was detected among ascomycetous yeasts isolated on grapes and during fermentation, suggesting a low occurrence of pectinolytic yeast species in wine fermentation ecosystem. This is the first study reporting R. dairenensis and Cr. saitoi species with pectinolytic activity. R. dairenensis GM-15 produced pectinases that proved to be highly active at grape pH, at 12 °C, and under ethanol and SO2 concentrations usually found in vinifications (pectinase activity around 1.1 U/mL). This strain also produced cellulase activity at 12 °C and pH 3.5, but did not produce P-glucosidase activity under these conditions. The strain showed encouraging enological properties for its potential use in low-temperature winemaking.Fil: Merín, María Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martín, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; ArgentinaFil: Rantsiou, Kalliopi. Università di Torino; ItaliaFil: Cocolin, Luca. Università di Torino; ItaliaFil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Isolation and selection of yeasts from wine grape ecosystem secreting cold-active pectinolytic activity
Full text linkThe present study was undertaken with the purpose of selecting yeasts from wine grapes that are able to produce extracellular cold-active pectinases. After two consecutive selections yeast isolates were identified by pheno- and genotyping, and pectinolytic activity was preliminarily characterised at proximate winemaking conditions. Out of 1023 indigenous microorganisms isolated from grape skins of D.O. San Rafael (Mendoza, Argentina) viticulture region, 565 (55%) showed pectinolytic activity on plates and, among them, 96 (17%) were chosen in a primary selection. Ten isolates were finally selected for exhibiting the greatest activity at low temperature (12. °C) and identified as Aureobasidium pullulans. GM-R-22 strain demonstrated the highest pectinolytic activity (0.751. U/mL) at pH 3.5 and 12. °C. Yeast pectinases were constitutively produced. This study is the first report about strains of A. pullulans producing pectinases which are able to show good activity at low temperature. These pectinolytic strains could be of interest in wine production.Fil: Merín, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; ArgentinaFil: Mendoza, Lucia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Farias, Marta Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Morata, Vilma Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentin
Sistemas enzimáticos microbianos que asisten en la maceración impactando en las propiedades físico-químicas y tecnológicas del vino
No full textEl vino es el producto de un proceso complejo en el que tiene lugar la conversión bioquímica del mosto de uva por acción de la microbiota levaduriforme y de múltiples reacciones químicas catalizadas por enzimas. Entre estas, las polisacaridasas degradan polímeros de paredes celulares de la baya de uva y mejoran diversos aspectos sensoriales y tecnológicos: extracción de jugo y rendimiento, clarificación, filtrabilidad, estabilidad coloidal, extracción de compuestos de aroma y color, y facilitan la liberación de polifenoles, entre los cuales se encuentran los compuestos bioactivos. El objetivo del presente trabajo fue seleccionar, en base al desempeño tecnológico en el proceso de vinificación, microorganismos autóctonos de la región DOC San Rafael-Mendoza, previamente aislados de superficie de uva, productores de sistemas multi-enzimáticos despolimerizantes de paredes celulares. Se realizó una primera selección en base a actividades enzimáticas pectinasas, celulasas, xilanasas, amilasas, β-glucosidasas y proteinasas. Mientras que la segunda selección se basó en la correlación entre la actividad enzimática y el efecto producido en el mosto. Para la producción de los extractos enzimáticos, las cepas se inocularon en medios de cultivos líquidos conteniendo pectina (1%) como inductor. Los cultivos fueron incubados en condiciones similares a las de vinificación (pH 3,8 y 28°C) durante 72 horas. La actividad pectinolítica se determinó valorando los azúcares reductores liberados desde un medio con pectina mediante el reactivo 3,5-dinitrosalicílico (DNS). Para evaluar el efecto de los extractos enzimáticos se realizó una maceración con 20 mL de mosto de uva, dosificados en idénticas unidades enzimáticas netas (EU), llevada a cabo por duplicado, a baja temperatura (12°C) y a temperatura tradicional de vinificación (28°C). Se realizaron controles con una enzima comercial de uso enológico y con mosto sin inocular (control negativo). Se realizaron ensayos de clarificación, filtrabilidad, determinación del índice de polifenoles totales (IPT), índice de color (IC), matiz, parámetros CIELAB y cuantificación de polifenoles totales. De un total de 21 cepas de levaduras, pertenecientes a 11 géneros, todas mostraron un marcado efecto de la actividad enzimática sobre los parámetros tecnológicos evaluados, respecto al control negativo. En cuanto al IPT una cepa de Aureobasidium pullulans presentó el mayor índice a ambas temperaturas de ensayo, presentando a su vez la mayor actividad pectinolítica. Se observó un notable aumento del IC respecto a los controles, efecto que fue más marcado a 28°C. Torulaspora delbrueckii tuvo marcada influencia de su actividad pectinolitica en la filtrabilidad y clarificación del mosto a ambas temperaturas de ensayo, como así también en la extracción de polifenoles totales a baja temperatura, diferenciándose del resto para estos efectos. Los resultados obtenidos sugieren que las levaduras seleccionadas en una primera instancia, pueden realizar un aporte positivo en cuanto a la degradación de polímeros presentes en el mosto, posibilitando su empleo en etapas de maceración tradicional y a bajas temperaturas. Del análisis de estos resultados se seleccionarán las mejores cepas con el perfil enzimático óptimo.Fil: Longhi, Sara Jaquelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; ArgentinaFil: Martín, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; ArgentinaFil: Morata, Vilma Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Bromatología - Alimentación. Area Biología; Argentin
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