Microencapsulation of Bifidobacterium animalis subsp lactis INL1 using whey proteins and dextrans conjugates as wall materials

The incorporation of probiotic bacteria to food products is restricted by their instability, so microencapsulation could provide them better protection during storage and gastrointestinal digestion. In this study Bifidobacterium animalis subsp. lactis INL1 was microencapsulated by spray drying using whey proteins isolate (WPI) and dextrans (DX of 6, 70 and 450 kDa) conjugates obtained by Maillard reaction as wall materials. The stability during storage time and temperature, the viability after simulated gastrointestinal digestion and the antioxidant capacity of the microcapsules were assayed. The cell viability was negatively affected by the gastrointestinal digestion and also over the storage time (12 months). Conjugate with DX 6 kDa was the most stable system at 25 degrees C and showed improved antioxidant capacity whit ABTS (+) technique; meanwhile with OH technique no differences were found among the samples. Free cells also showed antioxidant activity in all their fractions analyzed using the same techniques.