Influence of probiotic strain Bifidobacterium animalis subsp. lactis lafti b94, inulin and transglutaminase on the properties of set- style yoghurt

The aim of this research was to examine the influence of probiotic strain Bifidobacterium animalis subsp. lactis LAFTI B94, inulin and transglutaminase on quality and sensory properties of set-style yoghurt. Fresh, homogenized milk with 3,3% of milk fat was used for yoghurt production, with addition of Bifidobacterium animalis subsp. lactis LAFTI B94, inulin and transglutaminase activated during 1h 30 min at 55 °C. Enzyme inactivation was carried out by pasteurization of milk during 15 minutes at 85 °C. Control samples were prepared without addition of probiotic culture, inulin and transglutaminase. Physico-chemical parameters and sensory properties of produced set-style yoghurt have been determined. For reliable identification of probiotic strain Bifidobacterium animalis subsp. lactis LAFTI B94, isolated from the produced yoghurt, SDS-PAGE of whole cell proteins and PCR with species specific primers for Bifidobacterium were carried out. It has been shown that produced set-style yoghurt with probiotic strain Bifidobacterium animalis subsp. lactis LAFTI B94, inulin and transglutaminase had higher firmness, less syneresis and better sensory properties than control yoghurt samples. After 28 days of storage the viable count of Bifidobacterium animalis subsp. lactis LAFTI B94 was higher in samples containing inulin as prebiotic. Fermentation of yoghurt samples containing inulin and transglutaminase lasted shorter than fermentation of samples without inulin and transglutaminase. The presence of high number of probiotic culture (more than 106 cells/mL) in produced set yoghurts was confirmed by SDS-PAGE of whole cell proteins and PCR with species specific primers for Bifidobacterium