Influence of whey-based fruit juice containing Lactobacillus rhamnosus on intestinal well-being and humoral immune response in healthy adults

Valorization of Dairy By-Products, Sweet Whey, and Acid Whey, in the Production of Fermented Black Carrot Juice: A Comparative Study of the Phytochemical, Physicochemical, Microbiological, and Sensorial Aspects

The aims of this study were to improve the functional and nutritional properties of fermented black carrot juice by using sweet and acid whey in the production of fermented black carrot juice, to transform whey into a value-added product and to determine the effect of whey addition on the fermentation process. Whey was utilized as a water substitute in the formulation of the beverage prior to fermentation, and five distinct formulations were developed based on the type and proportion of whey (0% whey (control sample), 25% acid whey, 100% acid whey, 25% sweet whey, 100% sweet whey). Microbiological, sensorial, phytochemical, and physicochemical analyses were performed on samples taken during fermentation and on samples fermented and then resting. The addition of whey into the formulation resulted in an increase in acidity and turbidity of the beverage, with lower anthocyanin content observed in samples containing whey compared to the control throughout the fermentation process. The samples containing 100% whey exhibited lower a*, b*, h, and C* values and lower amounts of individual anthocyanins. The microbial load in these samples was high in the early stages of fermentation and reached a minimum towards the end of fermentation. The incorporation of whey led to an acceleration in the fermentation process, an enhancement in the microbiological characteristics of the beverage, and a substantial variation in phenolic compounds through the formation of a reversible protein complex. The resting process provided significant increases in color, anthocyanins, and gentisic and chlorogenic acids of whey-containing samples. The results showed that it is possible to produce whey-based functional fermented black carrot juice that is close to the control sample in terms of sensory and phytochemical properties and better than the control sample in terms of lactic acid bacteria count. It is recommended that both sweet and acid whey be utilized at a ratio of 25% in the production of fermented black carrot juice and to rest at 4 °C before consumption.

Bifidobacterium adolescentis and Lactobacillus rhamnosus alleviate non-alcoholic fatty liver disease induced by a high-fat, high-cholesterol diet through modulation of different gut microbiota-dependent pathways

The incidence of non-alcoholic fatty liver disease (NAFLD) has increased year on year, and the increasing appreciation of the importance of gut microbiota provides novel therapeutic avenues for the treatment of NAFLD. To explore the similarities and differences between lactic acid bacteria (LAB) known to alleviate NAFLD, we selected three strains of Bifidobacterium adolescentis and three strains of Lactobacillus rhamnosus to administer to C57BL/6J mice on a high-fat, high-cholesterol diet (HFHCD) for 23 weeks. Subsequently, the effects of the LAB were evaluated through various measures. The six LAB strains were found to have varying degrees of efficacy in the prevention of NAFLD. We found that there were interspecific and intraspecific differences in the beneficial effects, mainly with respect to energy metabolism, lipid metabolism and short-chain fatty acid concentration. Three strains of B. adolescentis and one strain of L. rhamnosus were found to relieve NAFLD by increasing the concentration of short-chain fatty acids in the intestine of NAFLD mice. The other two strains of L. rhamnosus, LGG and L10-1, relieved NAFLD through different ways, LGG modulated energy metabolism and lipid metabolism, and L10-1 reduced liver inflammation. Examination of gut microbiota indicated that the six LAB strains could block the HFHCD-induced elevation of Firmicutes/Bacteroidetes and alter the dominant species within the gut. These results suggest that B. adolescentis and L. rhamnosus can inhibit the development of NAFLD by regulating gut microbiota, and their use is thus a promising therapeutic strategy.

Effect of the fermentation pH on the storage stability of Lactobacillus rhamnosus preparations and suitability of in vitro analyses of cell physiological functions to predict it

AIMS

To investigate how cell physiological functions can predict the stability of freeze-dried probiotics. In addition, the effect of the fermentation pH on the stability of probiotics was investigated.

METHODS AND RESULTS

Fermenter-grown (pH 5.8 or 5.0) Lactobacillus rhamnosus cells were freeze-dried and their survival was evaluated during storage at 37 degrees C, in apple juice and during acid [hydrochloric acid (HCl) and malic acid] and bile exposure. Cells grown at pH 5.0 were generally coping better with acid-stress than cells grown at pH 5.8. Cells were more sensitive to malic acid compared with HCl. Short-term stability results of Lact. rhamnosus cells in malic acid correlated well with the long-term stability results in apple juice, whereas the results of cell membrane integrity studies were in accordance with bile exposure results.

CONCLUSIONS

Malic acid exposure can prove useful in evaluating the long-term stability of probiotic preparations in apple juice. Fermentation at reduced pH may ensure a better performance of Lact. rhamnosus cells during the subsequent acid-stress.

SIGNIFICANCE AND IMPACT OF THE STUDY

The beneficial effect of lowered fermentation pH to Lact. rhamnosus stability during storage in apple juice and the usefulness of malic acid test in predicting the stability were shown.