Water kefir is a non-dairy fermented beverage produced by a microbial consortium primarily composed of lactic acid bacteria(LAB),acetic acid bacteria(AAB),and various yeasts.Despite the expanding literature on its pro...Water kefir is a non-dairy fermented beverage produced by a microbial consortium primarily composed of lactic acid bacteria(LAB),acetic acid bacteria(AAB),and various yeasts.Despite the expanding literature on its probiotic potential,microbial data remain fragmented due to methodological heterogeneity across studies.This study systematically reviewed and meta-analyzed 96 studies on water kefir fermentation to assess microbial load,community composition,and influencing variables.Prevalent microbial taxa were identified,and the effects of substrate type,temperature,and grain source on microbial dynamics were evaluated.The pooled microbial loads were 6.86 log CFU/mL for LAB,6.05 for AAB,6.16 for yeasts,and 7.37 for total aerobic bacteria.Lactobacillus was the most frequently reported genus(27.96%),followed by Lactococcus(9.23%),Acetobacter(9.13%),Gluconobacter(6.34%),Saccharomyces(5.03%),and Leuconostoc(4.29%).At the species level,Saccharomyces cerevisiae,Gluconobacter oxydans,and Lactobacillus casei were among the most commonly identified.Fermentation conditions centered around 25℃and an incubation duration of 48-72 h consistently supported enhanced microbial activity across all microbial groups(6.5-7.5 log CFU/mL).Household-sourced grains yielded slightly higher LAB and yeast counts than commercial ones.Compared to white sugar,brown sugar led to significantly higher LAB counts(p=0.049)and a near-significant increase in AAB(p=0.073).Among frequently used supplements(fig,coconut,and grape),fig was associated with the highest LAB abundance.Overall,this metaanalysis offers a consolidated view of water kefir’s microbial composition and diversity.It highlights key fermentation variables that shape microbial outcomes,providing practical guidance for improving the consistency and functional quality of water kefir.展开更多
Milk and water kefir have been attractive to consumers as health-promoter fermented beverages.Although both are called“kefir”,they differ in physicochemical and microbial properties.In this study,we aimed to compare...Milk and water kefir have been attractive to consumers as health-promoter fermented beverages.Although both are called“kefir”,they differ in physicochemical and microbial properties.In this study,we aimed to compare milk and water kefir in terms of biomass increase,physicochemical properties,sensory qualities,and microbial loads incubated at different incubation temperatures(20℃,25℃,and 30℃)to mimic approximate room temperatures in various seasons.Additionally,the microbial diversity of the grains was compared through metagenomic analysis.The results showed that the biomass increase,physicochemical properties,and sensory analysis of milk kefir grains depended on the fermentation temperature(p<0.05);while in general,water kefir was not affected by the fermentation temperature.The highest total dry matter,protein,and fat content,and the least acidity were recorded at 20℃ in milk kefir drinks(p<0.05).Around 8 and 6 log CFU/ml microorganism loads(Lactobacillus spp.,Lactococcus spp.,yeasts,total aerobe,and anaerobe bacteria)were recorded for milk and water kefir drinks,respectively,regardless of the temperature.Bifidobacterium load was recorded as the lowest for both kefir drinks.The dominant species of bacteria and yeasts were determined as Lactobacillus parakefiri(21.28%)and Geotricum silvicola(65.10%)in milk kefir grain,and Lactobacillus nagelii(95.69%)and Dekkera bruxellensis(95.24%)in water kefir grain,respectively.The study showed that milk and water kefir differ in terms of physicochemical,sensory,and microbial aspects.Despite its low protein content,water kefir would be a probiotic substitute for milk kefir due to its probiotic features for vegans or people with lactose intolerance.展开更多
文摘Water kefir is a non-dairy fermented beverage produced by a microbial consortium primarily composed of lactic acid bacteria(LAB),acetic acid bacteria(AAB),and various yeasts.Despite the expanding literature on its probiotic potential,microbial data remain fragmented due to methodological heterogeneity across studies.This study systematically reviewed and meta-analyzed 96 studies on water kefir fermentation to assess microbial load,community composition,and influencing variables.Prevalent microbial taxa were identified,and the effects of substrate type,temperature,and grain source on microbial dynamics were evaluated.The pooled microbial loads were 6.86 log CFU/mL for LAB,6.05 for AAB,6.16 for yeasts,and 7.37 for total aerobic bacteria.Lactobacillus was the most frequently reported genus(27.96%),followed by Lactococcus(9.23%),Acetobacter(9.13%),Gluconobacter(6.34%),Saccharomyces(5.03%),and Leuconostoc(4.29%).At the species level,Saccharomyces cerevisiae,Gluconobacter oxydans,and Lactobacillus casei were among the most commonly identified.Fermentation conditions centered around 25℃and an incubation duration of 48-72 h consistently supported enhanced microbial activity across all microbial groups(6.5-7.5 log CFU/mL).Household-sourced grains yielded slightly higher LAB and yeast counts than commercial ones.Compared to white sugar,brown sugar led to significantly higher LAB counts(p=0.049)and a near-significant increase in AAB(p=0.073).Among frequently used supplements(fig,coconut,and grape),fig was associated with the highest LAB abundance.Overall,this metaanalysis offers a consolidated view of water kefir’s microbial composition and diversity.It highlights key fermentation variables that shape microbial outcomes,providing practical guidance for improving the consistency and functional quality of water kefir.
基金supported by the Scientific Research Projects Coordination Unit of Kirikkale University,project number 2022/017.
文摘Milk and water kefir have been attractive to consumers as health-promoter fermented beverages.Although both are called“kefir”,they differ in physicochemical and microbial properties.In this study,we aimed to compare milk and water kefir in terms of biomass increase,physicochemical properties,sensory qualities,and microbial loads incubated at different incubation temperatures(20℃,25℃,and 30℃)to mimic approximate room temperatures in various seasons.Additionally,the microbial diversity of the grains was compared through metagenomic analysis.The results showed that the biomass increase,physicochemical properties,and sensory analysis of milk kefir grains depended on the fermentation temperature(p<0.05);while in general,water kefir was not affected by the fermentation temperature.The highest total dry matter,protein,and fat content,and the least acidity were recorded at 20℃ in milk kefir drinks(p<0.05).Around 8 and 6 log CFU/ml microorganism loads(Lactobacillus spp.,Lactococcus spp.,yeasts,total aerobe,and anaerobe bacteria)were recorded for milk and water kefir drinks,respectively,regardless of the temperature.Bifidobacterium load was recorded as the lowest for both kefir drinks.The dominant species of bacteria and yeasts were determined as Lactobacillus parakefiri(21.28%)and Geotricum silvicola(65.10%)in milk kefir grain,and Lactobacillus nagelii(95.69%)and Dekkera bruxellensis(95.24%)in water kefir grain,respectively.The study showed that milk and water kefir differ in terms of physicochemical,sensory,and microbial aspects.Despite its low protein content,water kefir would be a probiotic substitute for milk kefir due to its probiotic features for vegans or people with lactose intolerance.
