Understanding the effect of fermentation time on physicochemical characteristics, sensory attributes, and volatile compounds in green tea kombucha.

Kombuchas are a trend in the fermented beverage field and the effect of fermentation time on their characteristics is necessary to better understand the process, mainly concerning volatile compounds, which are scarce information in the current literature. Thus, the present work aimed to evaluate the features of green tea kombucha during fermentation, monitoring the changes in pH, acidity, turbidity, polyphenols, ethanol, acetic acid, volatile compounds, and sensory profile and acceptance up to 14 days of fermentation. Kombuchas' pH and acidity decreased through time as expected, but after 4 days of fermentation, the beverage exceeded the Brazilian legal limits of acidity (130 mEq/L) and produced more than 0.5% AVB, which labels the beverage as alcoholic. Total polyphenols and condensed tannins content enhanced until the seventh day of fermentation and remained constant. Fermentation highly impacted the aroma of the infusion with a high formation of volatile acids, such as alcohols, esters, and ketones. Aldehydes were degraded during the bioprocess. Sensory characterization of kombucha showed that fermentation of 4 days increased perceived turbidity; vinegar, citric fruit, acid, and alcoholic aroma; and produced the beverage with sour, bitter, and vinegar flavor. Thus, the fermentation time of kombuchas must be controlled as they rapidly change and impact on the physicochemical parameters and sensory profile of the beverage can be negative.

Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice.

Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert antagonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 10(8) viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10, and after 10 days, challenged with SE86. The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection.

Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice

Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic -infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert anta-gonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 10(8) viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10,and after 10 days, challenged with SE86.The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection.