Probiotic viability and physico-chemical and sensory properties of plain and stirred fruit yogurts made from goat’s milk

Probiotic plain and stirred fruit yogurts were made from goat’s milk using bacterial cultures comprising, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Propionibacterium jensenii 702. The products were stored at 4 °C for 4 weeks, during which time the viability of the yogurt starter culture and probiotic bacteria was analysed weekly. P. jensenii 702 demonstrated the highest viability (108cfu/g) in all types of yogurt throughout the storage period, while the viability of the bifidobacteria (∼107 cfu/g) also remained above the minimum therapeutic level. The viability of L. acidophilus LA-5 fell below 106 cfu/g in yogurts, however, the addition of fruit juice appeared to support the viability of lactobacilli, with higher microorganism numbers observed in fruit yogurts than in plain yogurt throughout the shelf life. Addition of fruit juice significantly increased the syneresis, and decreased viscosity and water holding capacity of yogurts (p < 0.05), and also enhanced their sensory acceptability.