Twenty-two lactic acid bacteria (LAB) strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermop...Twenty-two lactic acid bacteria (LAB) strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus (UNSE314), Lactobacillus (L.) delbrueckii subsp, bulgaricus (UNSE309), L. rhamnosus (UNSE308), L. plantarum (UNSE287, UNSE316, UNSE317) and Pediococcus pentosaceus (UNSE315) strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity (ESA) was detected on ct-naphthyl (ct-NA) acetate and 13-naphthyl ([3-NA) acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.展开更多
Abstract:Objective To study the pathogen of root surface caries in the elderly. Methods Plaque samples from the experimental group and the control group were collected. After culturing in selective and non-selective m...Abstract:Objective To study the pathogen of root surface caries in the elderly. Methods Plaque samples from the experimental group and the control group were collected. After culturing in selective and non-selective media, the different bacteria were isolated. The counts and the positive rates of total bacteria, porphyromonas group, pervotella group, streptococcus mutants group, actinomyces group and lactobacillus group were compared.Results The counts of total bacteria, streptococcus mutants, actinomyces and lactobacillus of the experimental group were higher than those of the control group. The positive rates of actinomyces and lactobacillus of the experimental group were significantly higher than those of the control group. Conclusion Actinomyces and lactobacillus are the main related pathogens of root surface caries in the elderly.展开更多
文摘Twenty-two lactic acid bacteria (LAB) strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus (UNSE314), Lactobacillus (L.) delbrueckii subsp, bulgaricus (UNSE309), L. rhamnosus (UNSE308), L. plantarum (UNSE287, UNSE316, UNSE317) and Pediococcus pentosaceus (UNSE315) strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity (ESA) was detected on ct-naphthyl (ct-NA) acetate and 13-naphthyl ([3-NA) acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.
文摘Abstract:Objective To study the pathogen of root surface caries in the elderly. Methods Plaque samples from the experimental group and the control group were collected. After culturing in selective and non-selective media, the different bacteria were isolated. The counts and the positive rates of total bacteria, porphyromonas group, pervotella group, streptococcus mutants group, actinomyces group and lactobacillus group were compared.Results The counts of total bacteria, streptococcus mutants, actinomyces and lactobacillus of the experimental group were higher than those of the control group. The positive rates of actinomyces and lactobacillus of the experimental group were significantly higher than those of the control group. Conclusion Actinomyces and lactobacillus are the main related pathogens of root surface caries in the elderly.