Search results for "ACID BACTERIA"

Preliminary Investigation of Biogenic Amines in Type I Sourdoughs Produced at Home and Bakery Level

2022

During a survey for isolating sourdough lactic acid bacteria (LAB), 20 dough samples produced at the bakery level (BL) or home-made (HM) were collected. An enzyme-based colorimetric method revealed a total biogenic amines (BAs) concentration in the range 41.4–251.8 ppm for six (three BL and three HM) sourdoughs characterised by unpleasant odours. Eight BAs generally investigated in foods were identified and quantified from these six samples by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS). Only one HM sample contained almost all analysed BAs. Tryptamine was exclusively detected in HM sourdoughs (0.71–24.1 ppm). Putrescine, tryptamine, …

Approccio multiplo per l’indagine del microbiota dominante negli impasti acidi tradizionali siciliani

2011

Ecology of Vastedda della valle del Belìce cheeses: A review and recent findings to stabilize the traditional production

2018

The increasing request for classic foods has led to a higher demand for cheeses enjoying a “recognition of quality” status. This phenomenon has also affected Sicilian dairy products, in particular protected designation of origin (PDO) “Vastedda della valle del Belìce” (VdB), a cheese traditionally available only during the summer season, but requested year round. The variations of the microbial populations of raw milk among the seasons influence the microbiological quality of the cheeses produced. This review article reports the historical importance of cheeses and the traditional equipment used for dairy productions in Sicily with a specific focus on VdB. The microbial ecology of this chee…

Factors affecting the production of putrescine from agmatine by Lactobacillus hilgardii X1B isolated from wine

2008

Aims: To elucidate and characterize the metabolic putrescine synthesis pathway from agmatine by Lactobacillus hilgardii X1B. Methods and Results: The putrescine formation from agmatine by resting cells (the normal physiological state in wine) of lactic acid bacteria isolated from wine has been determined for the first time. Agmatine deiminase and N-carbamoylputrescine hydrolase enzymes, determined by HPLC and LC-Ion Trap Mass Spectrometry, carried out the putrescine synthesis from agmatine. The influence of pH, temperature, organic acids, amino acids, sugars and ethanol on the putrescine formation in wine was determined. Conclusions: Resting cells of Lact. hilgardii X 1B produce putrescine …

Advances in Wine Fermentation

2021

Fermentation is a well-known natural process that has been used by humanity for thousands of years, with the fundamental purpose of making alcoholic beverages such as wine, and also other non-alcoholic products. From a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid. The fermentation process turns grape juice (must) into wine. This is a complex chemical reaction whereby the yeast interacts with the sugars (glucose and fructose) in the must to create ethanol and carbon dioxide. Fermentation processes to produce wines are traditionally carried out with Saccharo…