摘要
Lactose, the sugar naturally present in milk, provides energy to lactic acid bacteria used in fermented dairy foods. Increasing concentrations of lactose may improve survivability of lactic acid bacteria in the dairy foods and in human gut enhancing their probiotic benefits. Acid tolerance is an important probiotic characteristic. The objective was to determine the influence of lactose on acid tolerance of yogurt starter culture </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> ST-M5 and </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> LB-12. The M 17 broth was used for </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;"> ST-M5 and MRS broth was used for</span><i> </i></span><i><span style="font-family:Verdana;"><i></span></i><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:""><span style="font-family:Verdana;">LB-12</span><i><span style="font-family:Verdana;">.</span></i><span style="font-family:Verdana;"> Lactose was added to both broths at 0% (control), 1%, 3%, and 5% (wt/vol). Both broths were acidified to pH 2.0. Upon sterilizing and tempering, both broths were inoculated. Acid tolerance </span></span><span style="font-family:Verdana;">was </span><span style="font-family:Verdana;">determined as viable counts in acidified broths after 120 minutes of incubations. In an incubation period of 2 hours, dilutions were plated every 30 minutes. Three replications were conducted. The highest acid tolerance for </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> ST-M5 and </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> LB-12, was observed in lactose concentration of 3% and 5% (wt/vol).
Lactose, the sugar naturally present in milk, provides energy to lactic acid bacteria used in fermented dairy foods. Increasing concentrations of lactose may improve survivability of lactic acid bacteria in the dairy foods and in human gut enhancing their probiotic benefits. Acid tolerance is an important probiotic characteristic. The objective was to determine the influence of lactose on acid tolerance of yogurt starter culture </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> ST-M5 and </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> LB-12. The M 17 broth was used for </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;"> ST-M5 and MRS broth was used for</span><i> </i></span><i><span style="font-family:Verdana;"><i></span></i><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:""><span style="font-family:Verdana;">LB-12</span><i><span style="font-family:Verdana;">.</span></i><span style="font-family:Verdana;"> Lactose was added to both broths at 0% (control), 1%, 3%, and 5% (wt/vol). Both broths were acidified to pH 2.0. Upon sterilizing and tempering, both broths were inoculated. Acid tolerance </span></span><span style="font-family:Verdana;">was </span><span style="font-family:Verdana;">determined as viable counts in acidified broths after 120 minutes of incubations. In an incubation period of 2 hours, dilutions were plated every 30 minutes. Three replications were conducted. The highest acid tolerance for </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Streptococcus thermophiles</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> ST-M5 and </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Lactobacillus bulgaricus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> LB-12, was observed in lactose concentration of 3% and 5% (wt/vol).
作者
Behannis Mena
Kayanush Aryana
Behannis Mena;Kayanush Aryana(School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Australia;School of Nutrition and Food Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, USA)
