Survival of encapsulated probiotic bacteria in Iranian yogurt drink (Doogh) after the product exposure to simulated gastrointestinal conditions

Microencapsulation of probiotic cells with hydrocolloid materials, as an efficient method of viability increase of probiotics, has been recently under special concern and investigation. In present study, the protective effect of microencapsulation with calcium alginate on survival of probiotic cells (Lactobacillus acidophilus La-5 and Bifidobacterium lactis Bb-12) incorporated in Iranian yogurt drink (Doogh) was studied after the product exposure to simulated gastrointestinal conditions. The 3 simulated gastrointestinal conditions were: reinforced/strict gastrointestinal condition (pH1.5-90 min/2% bile-90 min), semi-alleviated gastrointestinal condition (pH1.5-90 min/1 % bile-90 min) and real-alleviated gastrointestinal condition (pH2.0-30 min/0.6% bile-60 min). The viability of free probiotic cells increased from 0.6 and 0.2% (L. acidophilus and bifidobacteria, respectively) to 18.0 and 9.5% at reinforced gastrointestinal conditions, after encapsulation. At real-alleviated conditions, the cell survival rates were 16.1 % for L. acidophilus and 21 % for bifidobacteria before encapsulation, whilst these amounts improved to 26.3 and 34.0% (L. acidophilus and bificlobacteria, respectively) after encapsulation.