Effect of microencapsulation of Lactobacillus acidophilus LA-5 on physicochemical, sensory and microbiological characteristics of stirred probiotic yoghurt

- L. acidophilus LA-5 was microencapsulated with pectin and recovered with whey protein.
- Free and microencapsulated L. acidophilus LA-5 was added to stirred yoghurt.
- Probiotic yoghurt with LA-5 microencapsulated showed lower post-acidification.
- Microencapsulation protected L. acidophilus LA-5 during 35 days of refrigerated storage

The aim of this study was to evaluate the characteristics of probiotic stirred yoghurt and the survival of free and microencapsulated cells of Lactobacillus acidophilus LA-5 during refrigerated storage. L. acidophilus LA-5 was microencapsulated by ionic gelation and complex coacervation techniques using pectin and whey protein as wall and coating materials, respectively. The survival of probiotics subjected to conditions simulating the passage through the gastrointestinal tract and the sensory acceptance of yoghurts were evaluated after 35 days of refrigerated storage. The yoghurt containing encapsulated L. acidophilus LA-5 showed lower post-acidification and improved probiotics survival (62%) when compared to the yoghurt containing free cells of L. acidophilus LA-5 (10%) after 35 days of refrigerated storage. The encapsulated L. acidophilus LA-5 showed higher survival than the free microorganism during simulated gastrointestinal conditions. After 35 days of storage, no significant difference was observed for the attributes appearance, aroma, flavor, and overall impression for both samples. However, with respect to the attribute texture, the yoghurt containing encapsulated L. acidophilus LA-5 was less accepted than yoghurt containing free cells of L. acidophilus LA-5. Microencapsulation of L. acidophilus LA-5 by ionic gelation and complex coacervation provided lower post-acidification in probiotic yoghurts, and protection to the microorganism, during 35 days of refrigerated storage and during the passage through the simulated gastrointestinal conditions.