Search results for " fermentation"

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…

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…

Effect of lactic acid fermentation of lupine wholemeal on acrylamide content and quality characteristics of wheat-lupine bread

2013

The effect of supplementing wheat flour at a level of 15% with lupine (Lupinus angustifolius L.) wholemeal fermented by different lactic acid bacteria on acrylamide content in bread crumb as well as on bread texture and sensory characteristics was analysed. The use of fermented lupine resulted in a lower specific volume and crumb porosity of bread on an average by 14.1% and 10.5%, respectively, while untreated lupine lowered the latter parameters at a higher level (30.8% and 20.7%, respectively). The addition of lupine resulted in a higher by 43.3% acrylamide content compared to wheat bread (19.4 µg/kg dry weight (d.w.)). Results showed that acrylamide was significantly reduced using proteo…

Enological characterization of natural hybrids from Saccharomyces cerevisiae and S. kudriavzevii.

2007

The effect of yeasts on wine flavor response is of primary importance. The genus Saccharomyces, and mainly the species Saccharomyces cerevisiae, is responsible for alcoholic fermentation. Recently, several novel yeast isolates from wines have been described as hybrid yeasts between S. cerevisiae x S. kudriavzevii. We have analyzed their influence on two grape musts (Macabeo and Tempranillo) in fermentations conducted at four different temperatures (14, 18, 22 and 32 degrees C) by studying volatile compound production, sugar assimilation and other characteristics influencing the enological properties of wine caused by the impact of yeast. Hybrid yeasts behave particularly well at 14, 18 and …

Selenium bio-enrichment of Mediterranean fruit juices through lactic acid fermentation.

2021

Abstract This work was carried out to elaborate selenium (Se) bio-enriched fermented Mediterranean fruit juices. To this purpose, pomegranate and table red grape juices were added with sodium selenite (Na2SeO3) and fermented by Levilactobacillus brevis CRL 2051 and Fructobacillus tropaeoli CRL 2034 individually or combined. To better evaluate the effect of selenite addition and starter strain inoculums on the total bacterial community of the fruit juices, fermentation trials were performed with raw and pasteurized fruit juices. No statistical significant differences were observed for total mesophilic microorganisms (TMM) and rod-shaped lactic acid bacteria (LAB) levels among raw and pasteur…

Isolation and purification of enniatins A, A1, B, B1, produced by Fusarium tricinctum in solid culture, and cytotoxicity effects on Caco-2 cells

2010

Enniatins (ENs) are antibiotic compounds of hexadepsipeptidic structure produced by several strains of Fusarium spp. The ENs A, A(1), B, B-1 were purified from extracts of Fusarium tricinctum grown on a solid medium of corn, by a low pressure liquid chromatography (LPLC) on reverse phase of Amberlite XAD-7 followed by semipreparative LC. The purity and the structure of the isolated compounds were confirmed by LC-MS/MS. The technique of the purification of the fungal extract enabled complete separation of the ENs A, A(1), B, B-1 with a mean purity of 97% for all the compounds. The cytoxicity of the ENs was tested in the cell lines of human origin (epithelial colorectal adenocarcinoma cells, …

GC-MS as a tool to study the aromatic profiles of Candida zemplinina/ Saccharomyces cerevisiae mixed fermentation wines

2013

Comparative Transcriptomic Analysis Reveals Similarities and Dissimilarities in Saccharomyces cerevisiae Wine Strains Response to Nitrogen Availabili…

2015

Nitrogen levels in grape-juices are of major importance in winemaking ensuring adequate yeast growth and fermentation performance. Here we used a comparative transcriptome analysis to uncover wine yeasts responses to nitrogen availability during fermentation. Gene expression was assessed in three genetically and phenotypically divergent commercial wine strains (CEG, VL1 and QA23), under low (67 mg/L) and high nitrogen (670 mg/L) regimes, at three time points during fermentation (12 h, 24 h and 96 h). Two-way ANOVA analysis of each fermentation condition led to the identification of genes whose expression was dependent on strain, fermentation stage and on the interaction of both factors. The…

Yeasts Isolated from the Alcoholic Fermentation ofAgave duranguensisDuring Mezcal Production

2013

Mezcal is a spirit produced in some regions of Mexico. In the state of Durango, mezcal is produced via traditional fermentation of the Agave duranguensis plant. To better understand traditional fermentation processes, it is necessary to know which yeast species are present in fermentations in different producer regions. The aim of this research was to study yeasts involved in traditional mezcal fermentation in Durango, Mexico, and investigate the phylogeny of the native Saccharomyces cerevisiae strains involved in this process. The 5.8S-ITS genomic region was analyzed to identify strains present in the fermentation process samples in this study. To differentiate strains belonging to the gen…

Production of the Sicilian distillate “ Spiritu re fascitrari ” from honey by-products: An interesting source of yeast diversity

2017

The “Spiritu re fascitrari” (SRF) is a typical Sicilian distillate obtained from the by-products of traditional process of honey production. Although some alcoholic fermentation of honey based products have been described, the present research represents the first investigation on the yeast ecology and the physico-chemical characteristics of honey by-products subjected to an alcoholic fermentation followed by distillation. All samples collected during manufacturing process were analysed for the count of total, osmophilic and osmotolerant yeasts. The honeycombs and equipment surfaces showed the presence of yeasts that was 1.7 and 1.1 Log (CFU/mL), respectively. After enrichment, yeast popula…