Survival of Bifidobacterium longum LMG 13197 microencapsulated in Vegetal or Vegetal-inulin matrix in simulated gastrointestinal fluids and yoghurt

BACKGROUND Vegetal BM 297 ATO is a food grade lipid based material extracted from vegetables, and certified for human consumption. In this study, Bifidobacterium longum LMG 13197 was encapsulated in Vegetal BM 297 ATO-inulin by freeze drying, followed by evaluation of its survival in simulated gastrointestinal fluids and yoghurt. Furthermore, the effect of incorporation of such microparticles on physico-chemical properties of yoghurt was examined. Unencapsulated and encapsulated B. longum cells were exposed to simulated gastrointestinal fluids for 6 h and yoghurt at 4 °C for 6 weeks, and then evaluated for viability using plate counts. RESULTS By the end of exposure to simulated gastrointestinal fluids, encapsulated cells were >5 log units higher than their unencapsulated counterparts. Furthermore, their levels in yoghurt remained above 10(6) cfu mL(-1) until the end of 6 weeks of storage while unencapsulated levels were at this level up to 5 weeks. There were no significant differences in pH values of yoghurts containing encapsulated cells throughout the storage (p > 0.05). However, significant differences in the lightness and yellowness of these yoghurts were recorded, although the total colour change was negligible. CONCLUSIONS Vegetal-inulin encapsulation protected probiotics in gastrointestinal fluids and yoghurt with negligible effects to its appearance, thus can be used for fortification of yoghurt with probiotics.