AN IN VITRO COMPARATIVE ANALYSIS OF PROPERTIES OF PROBIOTIC BACTERIA PRESENT IN BEVERAGES

Abstract

Probiotics for human consumption including Lactobacillus sp. and Acetobacter sp. are of increasing interest due to the growing evidences of health advantages associated with them. The viability of these bacteria in food as well as during transit through the gastrointestinal tract is crucial for positive health effects. The present study comparatively analyzes the survivability and functional properties of commercial probiotic drinks in a simulated gastrointestinal environment. The sample drinks were divided into two sections viz.; Dairy and Non-dairy, both containing either Lactobacillus acidophilus or Acetobacter xylinum and estimated for properties including numbers, gram character, NaCl tolerance, bile salt resistance, optimal pH and production of organic acids. Viability and activity in the gastrointestinal environment was evaluated by subjecting the above to an in vitro digestive treatment using a combination of enzymes and digestive solutions. It was observed that amongst all the selected samples, Lactobacillus acidophilus present in the dairy beverages displayed the highest probiotic potential. These microorganisms displayed the greatest NaCl (1-9%) and bile salt tolerance (0.05- 0.4%) along with maximum organic acid production (1.81%), pH resistance (2.0-7.5) as well as overall survival during in vitro gastric, bile and intestinal digestion (p≤0.5). Moreover, non-dairy liquids with Acetobacter xylinum manifested improved performance compared to Lactobacillus in this food environment. Therefore, the functionality of a probiotic product may not only be dependent on the type of microorganism but also the food medium. Knowledge of the above may enable the consumer in making a careful selection of a desirable food product to gain maximum health benefits.