Isolation, identification, and potential probiotic characterization of one Lactococcus from Kefir grain

Effects of fungal based bioactive compounds on human health: Review paper

Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food.

Bioactive Compounds from Kefir and Their Potential Benefits on Health: A Systematic Review and Meta-Analysis

Despite evidence of health benefits from kefir administration, a systematic review with meta-analysis on bioactive compounds associated with these benefits is still absent in the literature. Kefir is fermented milk resulting from the metabolism of a complex microbiota in symbiosis. Recent researches have investigated the bioactive compounds responsible for the preventive and therapeutic effects attributed to kefir. However, differences in functional potential between industrial and artisanal kefir are still controversial. Firstly, we identified differences in the microbial composition among both types of kefir. Available evidence concerning the action of different bioactive compounds from kefir on health, both from in vitro and in vivo studies, was subsequently summarized to draw a primary conclusion of the dose and the intervention time for effect, the producer microorganisms, the precursor in the milk, and the action mechanism. Meta-analysis was performed to investigate the statistically significant differences (P < 0.05) between intervention and control and between both types of kefir for each health effect studied. In summary, the bioactive compounds more commonly reported were exopolysaccharides, including kefiran, bioactive peptides, and organic acids, especially lactic acid. Kefir bioactive compounds presented antimicrobial, anticancer, and immune-modulatory activities corroborated by the meta-analysis. However, clinical evidence is urgently needed to strengthen the practical applicability of these bioactive compounds. The mechanisms of their action were diverse, indicating that they can act by different signaling pathways. Still, industrial and artisanal kefir may differ regarding functional potential-OR of 8.56 (95% CI: 2.27-32.21, P ≤ .001)-according to the observed health effect, which can be associated with differences in the microbial composition between both types of kefir.

A review of nondairy kefir products: their characteristics and potential human health benefits

Functional foods are foods that, in addition to having nutrients, contain in their composition ingredients that act specifically on body functions associated with the control and reduction of the risk of developing some diseases. In this sense, kefir, a group of microorganisms in symbiosis, mainly yeasts and lactic acid bacteria, stands out. The trend of ingesting kefir has been focused on the development of products that serve specific consumers, such as those who are lactose-intolerant, vegans and vegetarians, and consumers in general who seek to combine the consumption of functional products with the improvement of their health and lifestyle. This overview provides an insight into kefir, presenting the technological process to produce a nondairy beverage and evidence of the benefits of its use to reduce the risk of disease. We also discuss regulatory aspects of products fermented using kefir. Until now, the use of kefir (isolated microorganism, kefiran, or fermented product) has demonstrated the potential to promote an increase in the number of bifidobacteria in the colon and an increase in the glycemic control while reducing the blood cholesterol and balancing the intestinal microbiota, which helps in reducing constipation and diarrhea, improving intestinal permeability, and stimulating and balancing the immune system. However, the literature still has gaps that need to be clarified, such as the consumption dose of kefir or its products to cause some health benefit.

Evaluation of Volatile Compounds during the Fermentation Process of Yogurts by Streptococcus thermophilus Based on Odor Activity Value and Heat Map Analysis

The volatile composition of yogurt produced by Streptococcus thermophilus fermentation at different time points was investigated by gas chromatography-mass spectrometry combined with simultaneous distillation and extraction. A total of 53 volatile compounds including 11 aldehydes, 10 ketones, 8 acids, 7 benzene derivatives, 13 hydrocarbons, and 4 other compounds were identified in all of the samples. Ketones and hydrocarbons were the predominant volatile components in the early stage, whereas acids were the predominant volatiles in the late stage. The importance of each volatile was evaluated based on odor, threshold, and odor activity values (OAVs). Twenty-nine volatiles were found to be odor-active compounds (OAV > 1), among which (E, E)-2,4-decadienal had the highest OAV (14623–22278). Other aldehydes and ketones such as octanal, dodecanal, 2-nonen-4-one, and 2-undecanone also showed high odor intensity during fermentation. Heat map analysis was employed to evaluate the differences during fermentation. The results demonstrated that the volatile profile based on the content and OAVs of volatile compounds enables the good differentiation of yogurt during fermentation.

Identification and Evaluation of Probiotic Potential in Yeast Strains Found in Kefir Drink Samples from Malaysia

Kefir drink is a source of probiotic microorganism with remarkable functional and technological properties. The objective of this work is to isolate yeast strains from Malaysian kefir drink and evaluate them for probiotic potentials. In the present study, nine strains of probiotic yeast were isolated from a Malaysian kefir drink and identified according to their 16S rDNA sequences. Furthermore, their probiotic potential was evaluated. The probiotic properties were tested for aspects of antibiotic susceptibility, antimicrobial activity, and gastrointestinal condition tolerance (pH and temperature). Five isolated strains, M3, Y5, Y9, Y11 and A1, showed good tolerance towards low pH condition while three strains, A1, M1, and M3, showed antimicrobial activity against E. coli, P. aeruginosa, and Salmonella sp. Most isolates were resistant to penicillin, streptomycin, and ampicillin, and grew well at human body temperature. The result of this test indicates that the yeast strains isolated from Malaysian kefir drink have excellent potential for use as probiotics in various products. Lastly, kefir milk is one of the excellent source of probiotic yeast strains and could be used as a new yeast probiotic formulation or in food supplements.

Screening of aroma-producing lactic acid bacteria and their application in improving the aromatic profile of yogurt

The development of yogurt flavor is a complicated and dynamic biochemical process. In addition to traditional starter cultures, adjunct cultures could also make significant contributions to the flavor profiles of yogurt. In the current study, two Lactobacillus plantarum strains (1-33 and 1-34) were isolated based on their abilities to produce acetaldehyde and diacetyl. In co-fermentation with traditional starters, these isolated strains were able to maintain viability without affecting the yogurt's acidification profiles. Furthermore, they positively influenced the aroma quality of the yogurt samples. They promoted the formation of volatile metabolites, especially acetaldehyde, diacetyl, and acetoin, which are recognized as characteristic compounds. The results of this work provide novel knowledge about the contributions of isolated strains on the flavor profiles of yogurt, which will help to improve the organoleptic properties of the final products. PRACTICAL APPLICATIONS: Using lactic acid bacteria (LAB) as adjunct cultures co-fermented with traditional yogurt starter cultures can increase the quantities of flavor compounds in yogurt. This study enriches our understanding of the effects of adjunct cultures on yogurt flavor. Researchers and manufacturers that specialize in yogurt making can use the results of this study to improve the aromatic profile and organoleptic quality of yogurt.

Characterization and screening of the potential probiotic lactic acid bacteria and Bifidobacterium strains isolated of different biotopes

The use of lactic acid bacteria (LAB) and bifidobacteria species as probiotics may help to reduce antibiotic use for therapeutic, prophylactic and growth promotion in animal husbandry. The choice of the starter cultures has a critical impact on the palatability, processability and nutritional attributes of fermented products. In our research, the aim of this study was to screen and select potent probiotic LAB and Bifidobacterium strains isolated from different niches and to evaluate their characteristic features. A total of fourteen LAB and fifty-four Bifidobacterium were isolated from four fresh cows and camel’s milk, and twenty stool samples of healthy new born infants were identified and characterized by morphology and biochemical tests in order to select most suitable strains according to their technological characteristics including probiotic proprieties, antibiotics resistance and in vitro antagonism against food-poisoning bacteria. When the results of tolerance to both gastric and bile juices are taken together it appears that between fourteen LAB and forty-five, the strain B. longum BHI 07 has significantly the highest ability to survive during gastrointestinal transit (P < 0.05). Therefore, the mixed cultures of Bf. longum strains with LAB strains were more active against pathogenic bacteria than the pure one. These results show that bifidobacteria isolated from infants may be useful for improving probiotic formulae with respect to protection against pathogenic bacteria responsible of infection.

Effect of Lactobacillus gasseri BNR17 on irritable bowel syndrome: a randomized, double-blind, placebo-controlled, dose-finding trial

Lactobacillus gasseri BNR17 is a strain isolated from human breast milk. The objective of this randomized, double-blind, placebo-controlled, and preliminary dose-finding trial was to find the effective dose and evaluate the effect of Lb. gasseri BNR17 on irritable bowel syndrome (IBS) symptoms. A total of 55 volunteers aged over 20 years with body mass index over 23 kg/m² were randomized to intake a placebo, low-dose (BNR-L, 2 × 10⁸ CFU/day), intermediate-dose (BNR-M, 2 × 10⁹ CFU/day), or high-dose BNR (BNR-H, 2 × 5 × 10⁹ CFU/day) for four weeks. Questionnaire for IBS symptoms scores and Lb. gasseri BNR17 in feces were assessed at the beginning and end of the trial. Among IBS symptoms scores, abdominal pain score was significantly reduced in BNR-H group. Lb. gasseri BNR17 was detected in all intake groups except placebo. In the preliminary study, Lb. gasseri BNR17 was confirmed to have probiotic properties.

Functional and bioinformatics analysis of an exopolysaccharide-related gene (epsN) from Lactobacillus kefiranofaciens ZW3

A novel lactic acid bacteria strain Lactobacillus kefiranofaciens ZW3 exhibited the characteristics of high production of exopolysaccharide (EPS). The epsN gene, located in the eps gene cluster of this strain, is associated with EPS biosynthesis. Bioinformatics analysis of this gene was performed. The conserved domain analysis showed that the EpsN protein contained MATE-Wzx-like domains. Then the epsN gene was amplified to construct the recombinant expression vector pMG36e-epsN. The results showed that the EPS yields of the recombinants were significantly improved. By determining the yields of EPS and intracellular polysaccharide, it was considered that epsN gene could play its Wzx flippase role in the EPS biosynthesis. This is the first time to prove the effect of EpsN on L. kefiranofaciens EPS biosynthesis and further prove its functional property.