Search results for "FERMENTATION"

Biogenic amine determination in wine fermented in oak barrels: Factors affecting formation

2008

Changes in biogenic amines (histamine, putrescine, tyramine and cadaverine) were monitored during the industrial production of Tempranillo and Cabernet Sauvignon wines. The origin of these amines in relation to the presence of different lactic bacteria (indigenous or inoculated) during malolactic fermentation, while aging in oak barrel, and the correlations between amines and their corresponding amino acids were statistically evaluated. In this study we found that there was a greater increase in amines post malic acid depletion than during malolactic fermentation and that more amines were produced in wine of the Tempranillo variety. The total amino acid concentration was 1.6 times greater i…

Principal Parameters of Grape Ripening and Wine Fermentation

2008

Dynamics of Microbial Populations during Fermentation of Wines from the Utiel-Requena Region of Spain

1989

The dynamics of fungi, yeasts, and lactic acid bacteria during fermentation of four musts were studied. Fungi disappeared quickly in the fermenting must. The lactic acid bacteria population diminished during alcoholic fermentation, then they increased and performed malolactic fermentation. Yeasts grew quickly, reaching maximum populations at different times depending on the vinification treatment.

Interactions micro-organismes - bois et impact sur les propriétés physico-chimiques du vin : fermentation malolactique par le biofilm de Oenococcus o…

2015

Malolactic fermentation improves wine quality, mainly by decreasing acidity. It is carried out by lactic acid bacteria, mainly Oenococcus oeni. This species is favored for its efficiency and its organoleptic outcome. O. oeni ability to withstand wine stress and to keep its fermentation activity is a subject of major interest.Samples of oak showed that O. oeni adheres to wood and is able to persist for several months in wine. However, in the majority of natural habitats, microorganisms grow attached to a surface, within a structured ecosystem called biofilm. In this form of life, cells benefit from an increased stress resistance.These two properties, adherence to a surface and stress resista…

Generalized model of the effect of pH on lactate fermentation and citrate bioconversion in Lactococcus lactis ssp. Lactis biovar. diacetylactis

1994

An aroma-imparting mesophilic lactic starter (Lactococcus lactis ssp. lactis biovar. diacetylactis) was studied in batch culture in medium with 50 g·l−1 lactose and 2 g·l−1 citrate. The effect of pH on the physiology of growth and the production of flavour compounds was investigated with a mathematical model. The specific rates of growth and of lactose fermentation obeyed a law of non-competitive inhibition by lactic acid produced, inhibition increasing as the pH of the medium decreased. The pH thus acted indirectly by increasing the proportion of non-dissociated lactic acid, identified as the inhibiting form of lactic acid. The generalized model, taking into account the effect of pH, was t…

Technological and molecular diversity of Lactobacillus plantarum strains isolated from naturally fermented sourdoughs.

2004

Thirty Lactobacillus (L.) plantarum strains, isolated from sourdough, were identified by biochemical tests as well as 16S rDNA sequencing and differentiated on the basis of technological properties, such as amylase, protease, phytase and antirope activities. These properties were shown to be widely differing among the strains, indicating a significant technological diversity. Genetic differentiation was achieved by restriction endonuclease analysis-pulsed field gel electrophoresis (REA-PFGE) that allowed the L. plantarum strains to be divided into 10 different genomic groups. Moreover, 32 different starters were employed in dough making experiments; each starter consisted of a single strain…

Could halophilic archaea improve the traditional salted anchovies (Engraulis encrasicholus L.) safety and quality?

2010

Aims:  The positive influence of two selected extremely halophilic archaea strains in the production of salted anchovies (Engraulis encrasicolus, L., 1758) was highlighted. Methods and Results:  Anchovies produced with salt artificially contaminated with halophiles exhibited lower loads of staphylococci, Enterobacteriaceae and lactic acid bacteria, and a reduced content of histamine as well as an improved organoleptic acceptance. Conclusions:  The findings of this survey are expected to enhance the safety of salted anchovies, with regard to the histamine formation during ripening, and to improve the sensory attributes of this product. Significance and Impact of the Study:  This study repres…

Study on the application of an interspecific competition model for the prediction of microflora behaviour during the fermentation process of S. Angel…

2009

The use of predictive microbiology models able to evaluate bacterial behaviour as a function of environmental conditions and, at the same time, of natural microflora competition was considered by several authors with different approaches. Some authors modelled bacterial competition as a function of metabolic product with particular regard to lactic acid and modelled interspecific bacterial competition introducing a term into a conventional primary predictive model, which gives account for the interaction between two populations, so that they inhibit each other to the same extent that they inhibit their own growth.

Development of new non-dairy beverages from Mediterranean fruit juices fermented with water kefir microorganisms

2016

The aim of this work was to explore the use of several Mediterranean fruit juices as fermentable substrates to develop new non-dairy fermented beverages. Microbiological, chemical and sensory features of kefir-like beverages obtained after the fermentation of juices extracted from fruits cultivated in Sicily (southern Italy) with water kefir microorganisms were investigated. Results indicated that both lactic acid bacteria and yeasts were able to develop in the fruit juices tested, but the highest levels were registered with prickly pear fruit juice. All fruit juices underwent a lactic fermentation, since a lactic acid content was detected in the resulting kefir-like beverages. Except kiwif…

Anaerobic digestion of grass silage in batch leach bed processes for methane production.

2007

Abstract Anaerobic digestion of grass silage in batch leach bed reactors, with and without a second stage upflow anaerobic sludge blanket (UASB) reactor, was evaluated. Sixty six percent of the methane potential in grass was obtained within the 55 days solids retention time in the leach bed–UASB process without pH adjustment, whereas in the one-stage leach bed process 20% of the methane potential in grass was extracted. In two-stage operation, adjustment of the pH of influent to the leach bed reactor to 6 with HCl led to inhibition of both hydrolysis/acidogenesis and methanogenesis. In the leach bed–UASB process 39% of the carbohydrates and 58% of the acid soluble lignin were solubilised wi…