Kefir is a probiotic fermented milk product,distributed throughout the world from the North Caucasus,formed by fermenting milk with kefir grains.Kefir grains represent a striking example of microbial symbiosis between...Kefir is a probiotic fermented milk product,distributed throughout the world from the North Caucasus,formed by fermenting milk with kefir grains.Kefir grains represent a striking example of microbial symbiosis between bacteria and fungi.Despite the extensive shifts in microbial composition during milk fermentation,the composition of kefir grains remains relatively constant.The evolutionary origin of such a stable symbiont remains unclear.There are multiple reports of differences between commercial kefir-like products and kefir prepared according to traditional techniques by fermenting milk with indigenous kefir grains.Modern research is aimed at studying the health properties of kefir and kefir grain components.To accurately represent the evolutionary origin of kefir grains,the characteristics of important species or consortia for the development of new promising products,it is essential to study the composition of samples of historical kefir origin,particularly the Karachay-Cherkess and Kabardino-Balkarian Republics of the North Caucasus.展开更多
Increased accumulation of oxytetracycline(OTC)in environmental water bodies could potentially lead to its accumulation in human body,thereby damaging human intestinal tract.Dietary interventions could be helpful for r...Increased accumulation of oxytetracycline(OTC)in environmental water bodies could potentially lead to its accumulation in human body,thereby damaging human intestinal tract.Dietary interventions could be helpful for recovery of intestinal morphology and function.Therefore,this study set zebrafish as model to explore the potential of kefir supplementation in the recovery of intestinal damage caused by exposure to OTC.In experiments by zebrafish,the rearing units used were glass tanks,each with volume of 5 L.The tanks were stocked with 12 zebrafish each.For each treatment,there were 8 replicate tanks.The zebrafish were treated with OTC followed by the addition of kefir to the food.The results showed positive improvements with kefir supplementation.Kefir treatment mitigated intestinal inflammation by reducing the levels of TNF-α,IL-6,and IL-1β;enhancing the activity of the antioxidant enzymes catalase,superoxide dismutase,glutathione peroxidase and increasing the gene expression of intestinal tight junction proteins(ZO-1a and ZO-1b).These effects were beneficial for reversing reduced integrity of intestinal barrier caused by OTC.Moreover,kefir helped to reverse the disruption of gut microbiota caused by OTC and further impacted host metabolism.Specifically,Lactobacillus kefiranofaciens and Lactobacillus kefiri,which were derived from the kefir microbiota,were found to be enriched in the zebrafish intestine.This helped to inhibit the increased abundance of some Proteobacteria species induced by OTC treatment.Liver metabolomics analysis revealed that kefir improved OTC-induced disruptions in the tricarboxylic acid cycle,glycerophospholipid and amino acid metabolism.The differentially abundant metabolites identified included a total of 80 types after OTC exposure,with the abundance of 74 kinds significantly reversed following kefir treatment.Correlation analysis revealed that certain Proteobacteria species and above Lactobacillus species were closely linked with metabolic inhibition in zebrafish caused by OTC and metabolic restoration caused by kefir treatment,respectively.展开更多
To obtain the optimization formulation of pure cultures in Tibetan kefir, the influence of the different mixtures of five strains in the pure cultures in Tibetan kefir on the flavor components in fermented milk was st...To obtain the optimization formulation of pure cultures in Tibetan kefir, the influence of the different mixtures of five strains in the pure cultures in Tibetan kefir on the flavor components in fermented milk was studied using the mixture design. The regression model on microorganism composition and main metabolites was established. The results suggested that the predictable production of lactate reached the maximum of 8.16 g L-1, while the most predictable production of diacetyl, ethanol, and CO2 were 77.23 mg L-1, 4259 mg L-1, and 2.12 g L-1, respectively. Based on these, the response values that satisfied all expectations were optimized, and the most excellent combination was Lactococcus lactis 27%, Leuconostoc mesenteroides 37%, Lactobacillus kefiri 11%, Lactobacillus casei 10%, and Kluyveromyces rnarxianus 15%. With the aid of analysis software （Design-expert 6.0.5）, the formulation of pure cultures in Tibetan kefir can be optimized for several responses and the best formulation can be obtained.展开更多
Diabetes mellitus is a predominant chronic disease which causes mortality of millions of people yearly. Its prevalence is on the rise worldwide. Water kefir is fermented food produced by a matrix of polysaccharides co...Diabetes mellitus is a predominant chronic disease which causes mortality of millions of people yearly. Its prevalence is on the rise worldwide. Water kefir is fermented food produced by a matrix of polysaccharides containing bacteria and yeasts, with therapeutic properties. Our study aimed to evaluate anti-hyperglycemic and anti-hyperlipidemic activities of water kefir on streptozotocin-induced diabetic Wistar rats. Adult Wistar rats were made diabetic by intraperitoneal injection of streptozotocin, and were given or not kefir in drinking water for 5 weeks. Body weight, glucose and lipid levels were measured. The results demonstrated evident improvement in body weight, glucose, and lipid profiles of treated rats comparing with diabetic or control rats. Water kefir is found to be less cost hypoglycemic and hypolipidimic treatment and less time consuming. Water kefir can potentially be useful food for diabetes to control glucose and lipid levels.展开更多
Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates...Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.展开更多
The main objective of this study was the analysis of physicochemical and rheological behavior of a drinkable beverage prepared with different concentrations(5%,10%and 20%w/w)of Kefir.Several rheological models were al...The main objective of this study was the analysis of physicochemical and rheological behavior of a drinkable beverage prepared with different concentrations(5%,10%and 20%w/w)of Kefir.Several rheological models were also evaluated to determine the model that better fit experimental data.Apparent viscosity was measured with a Brookfield Viscometer within shear rates of 0.26 rad/s to 2.09 rad/s;and with an Ar-2000ex TA Instruments Rheometer within shear rates of 0.01 rad/s to 1,000 rad/s.Physicochemical tests,such as titratable acidity,chloride percent,fat concentration,color,humidity,syneresis,and total solids,were determined using laboratory equipment.The main result observed in all samples tested with Brookfield viscometer was that Kefir drink behaved as a Newtonian Fluid within shorter strain rates(0.26 rad/s to 2.09 rad/s).However,when the same samples were tested with Ar-2000ex Rheometer,a different behavior was observed:Over a wider range of shear rates,the fully non-Newtonian behavior of Kefir samples was discovered.Besides,additional variables such as shear and normal stresses,and loss and storage modulus,were analyzed with Ar-2000ex Rheometer.The rheological model that better fitted the experimental data was Cross model,followed by Power Law Model.Statistical analysis of viscosity data acquired with Brookfield Viscometer from all Kefir concentrations was not significant(p values greater than 0.05);which demonstrated that the effect of Kefir concentration over shorter strain rates was not significant,and thus,the samples behave as a Newtonian fluid.On the other hand,p values lower than 0.05 were observed in most of the different Kefir concentration samples tested with Ar-2000ex Rheometer;which indicates that a statistical significant effect was observed and thus a non-Newtonian behavior of Kefir samples.All statistical analysis was performed with SPSS v.16 software,selecting a Duncan Test with a confident interval of 95%to accept or reject the variances compared of the different Kefir concentration samples.展开更多
文摘Kefir is a probiotic fermented milk product,distributed throughout the world from the North Caucasus,formed by fermenting milk with kefir grains.Kefir grains represent a striking example of microbial symbiosis between bacteria and fungi.Despite the extensive shifts in microbial composition during milk fermentation,the composition of kefir grains remains relatively constant.The evolutionary origin of such a stable symbiont remains unclear.There are multiple reports of differences between commercial kefir-like products and kefir prepared according to traditional techniques by fermenting milk with indigenous kefir grains.Modern research is aimed at studying the health properties of kefir and kefir grain components.To accurately represent the evolutionary origin of kefir grains,the characteristics of important species or consortia for the development of new promising products,it is essential to study the composition of samples of historical kefir origin,particularly the Karachay-Cherkess and Kabardino-Balkarian Republics of the North Caucasus.
基金financially supported by the Zhejiang Zhongmengchang Health Technology Co.,Ltd.
文摘Increased accumulation of oxytetracycline(OTC)in environmental water bodies could potentially lead to its accumulation in human body,thereby damaging human intestinal tract.Dietary interventions could be helpful for recovery of intestinal morphology and function.Therefore,this study set zebrafish as model to explore the potential of kefir supplementation in the recovery of intestinal damage caused by exposure to OTC.In experiments by zebrafish,the rearing units used were glass tanks,each with volume of 5 L.The tanks were stocked with 12 zebrafish each.For each treatment,there were 8 replicate tanks.The zebrafish were treated with OTC followed by the addition of kefir to the food.The results showed positive improvements with kefir supplementation.Kefir treatment mitigated intestinal inflammation by reducing the levels of TNF-α,IL-6,and IL-1β;enhancing the activity of the antioxidant enzymes catalase,superoxide dismutase,glutathione peroxidase and increasing the gene expression of intestinal tight junction proteins(ZO-1a and ZO-1b).These effects were beneficial for reversing reduced integrity of intestinal barrier caused by OTC.Moreover,kefir helped to reverse the disruption of gut microbiota caused by OTC and further impacted host metabolism.Specifically,Lactobacillus kefiranofaciens and Lactobacillus kefiri,which were derived from the kefir microbiota,were found to be enriched in the zebrafish intestine.This helped to inhibit the increased abundance of some Proteobacteria species induced by OTC treatment.Liver metabolomics analysis revealed that kefir improved OTC-induced disruptions in the tricarboxylic acid cycle,glycerophospholipid and amino acid metabolism.The differentially abundant metabolites identified included a total of 80 types after OTC exposure,with the abundance of 74 kinds significantly reversed following kefir treatment.Correlation analysis revealed that certain Proteobacteria species and above Lactobacillus species were closely linked with metabolic inhibition in zebrafish caused by OTC and metabolic restoration caused by kefir treatment,respectively.
文摘To obtain the optimization formulation of pure cultures in Tibetan kefir, the influence of the different mixtures of five strains in the pure cultures in Tibetan kefir on the flavor components in fermented milk was studied using the mixture design. The regression model on microorganism composition and main metabolites was established. The results suggested that the predictable production of lactate reached the maximum of 8.16 g L-1, while the most predictable production of diacetyl, ethanol, and CO2 were 77.23 mg L-1, 4259 mg L-1, and 2.12 g L-1, respectively. Based on these, the response values that satisfied all expectations were optimized, and the most excellent combination was Lactococcus lactis 27%, Leuconostoc mesenteroides 37%, Lactobacillus kefiri 11%, Lactobacillus casei 10%, and Kluyveromyces rnarxianus 15%. With the aid of analysis software （Design-expert 6.0.5）, the formulation of pure cultures in Tibetan kefir can be optimized for several responses and the best formulation can be obtained.
文摘Diabetes mellitus is a predominant chronic disease which causes mortality of millions of people yearly. Its prevalence is on the rise worldwide. Water kefir is fermented food produced by a matrix of polysaccharides containing bacteria and yeasts, with therapeutic properties. Our study aimed to evaluate anti-hyperglycemic and anti-hyperlipidemic activities of water kefir on streptozotocin-induced diabetic Wistar rats. Adult Wistar rats were made diabetic by intraperitoneal injection of streptozotocin, and were given or not kefir in drinking water for 5 weeks. Body weight, glucose and lipid levels were measured. The results demonstrated evident improvement in body weight, glucose, and lipid profiles of treated rats comparing with diabetic or control rats. Water kefir is found to be less cost hypoglycemic and hypolipidimic treatment and less time consuming. Water kefir can potentially be useful food for diabetes to control glucose and lipid levels.
文摘Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.
文摘The main objective of this study was the analysis of physicochemical and rheological behavior of a drinkable beverage prepared with different concentrations(5%,10%and 20%w/w)of Kefir.Several rheological models were also evaluated to determine the model that better fit experimental data.Apparent viscosity was measured with a Brookfield Viscometer within shear rates of 0.26 rad/s to 2.09 rad/s;and with an Ar-2000ex TA Instruments Rheometer within shear rates of 0.01 rad/s to 1,000 rad/s.Physicochemical tests,such as titratable acidity,chloride percent,fat concentration,color,humidity,syneresis,and total solids,were determined using laboratory equipment.The main result observed in all samples tested with Brookfield viscometer was that Kefir drink behaved as a Newtonian Fluid within shorter strain rates(0.26 rad/s to 2.09 rad/s).However,when the same samples were tested with Ar-2000ex Rheometer,a different behavior was observed:Over a wider range of shear rates,the fully non-Newtonian behavior of Kefir samples was discovered.Besides,additional variables such as shear and normal stresses,and loss and storage modulus,were analyzed with Ar-2000ex Rheometer.The rheological model that better fitted the experimental data was Cross model,followed by Power Law Model.Statistical analysis of viscosity data acquired with Brookfield Viscometer from all Kefir concentrations was not significant(p values greater than 0.05);which demonstrated that the effect of Kefir concentration over shorter strain rates was not significant,and thus,the samples behave as a Newtonian fluid.On the other hand,p values lower than 0.05 were observed in most of the different Kefir concentration samples tested with Ar-2000ex Rheometer;which indicates that a statistical significant effect was observed and thus a non-Newtonian behavior of Kefir samples.All statistical analysis was performed with SPSS v.16 software,selecting a Duncan Test with a confident interval of 95%to accept or reject the variances compared of the different Kefir concentration samples.
