Abstract Soymilk was produced from vegetable soybean and fermented by probiotics (Lactobacillus acidophilus La-5, Bifidobacterium animalis Bb-12) in co-culture with Streptococcus thermophilus. The composition of the fermented beverage and oligosaccharides content were determined. The effect of fructooligosaccharides and inulin on the fermentation time and viability of probiotic microorganisms throughout 28 days of storage at 5 °C were evaluated. The soymilk from vegetable soybeans was fermented in just 3.2 h, when pH reached 4.8. Fermentation reduced the contents of stachyose and raffinose in soymilk. Prebiotics had no effect on acidification rate and on viability of B. animalis and S. thermophilus in the fermented beverage. The viable counts of B. animalis Bb-12 remained above 108 CFU mL-1 in the fermented soymilk during 28 days of storage at 5 °C while L. acidophilus La-5 was decreased by 1 log CFU mL-1. The fermented soymilk from vegetable soybeans showed to be a good food matrix to deliver probiotic bacteria, as well as a soy product with a lower content of non-digestible oligosaccharides.
Subject(s)Beverages/analysis , Soy Milk/metabolism , Streptococcus thermophilus/metabolism , Synbiotics , Bifidobacterium animalis/metabolism , Lactobacillus acidophilus/metabolism , Oligosaccharides/analysis , Temperature , Colony Count, Microbial , Soy Milk/isolation & purification , Streptococcus thermophilus/growth & development , Microbial Viability/drug effects , Microbial Viability/radiation effects , Fermentation , Bifidobacterium animalis/growth & development , Hydrogen-Ion Concentration , Inulin/analysis , Lactobacillus acidophilus/growth & development
Background: There is a genuine interest in the development of probiotic milk and juice based beverages because they are a good-vehicle to deliver probiotic microorganisms to consumers. For this purpose, the viability and metabolism of four probiotic strains (Lactobacillus acidophilus LA5, Bifidobacterium lactis BB12, L. rhamnosus and L. plantarum) were studied in non-fermented milk and carrot juice mix drink. The drinks were evaluated in 5 days interval for viable cell count, pH, acidity, sedimentation and sensory quality during refrigerated storage at 4 ± 2ºC for up to 20 days. Results: The results showed that all strains had good viability in milk/carrot juice drink (88-98%), but L. acidophilus LA5 seemed more stable than three other strains. The levels of pH and acidity were ranged 5.33-6.6 and 0.13-0.31%, respectively. The drinks inoculated with L. rhamnosus and control (non-probiotic) showed more variation in pH and acidity. The most sedimentation was detected in drinks inoculated with L. rhamnosus, reaching 3.73 mL/10 mL sample. Sensory assessment indicated lowest acceptability in control and milk/carrot juice drink inoculated with L. rhamnosus, respectively. Conclusion: This study indicated that some probiotic bacteria can be applied by food producers to produce functional drinks with an increased shelf-life.