Comparison of conjugated linoleic acid production in Bifidobacterium sp . and Lactobacillus acidophilus probiotic yoghurt

The aim of this study was to assess the strains of probiotic bacteria in yoghurt for their ability to produce CLA from free linoleic acid. The effect of process variables was investigated on increasing of CLA in probiotic yoghurt. Two different set of microorganism consists of L. acido philus, B. lactis and traditional yoghurt starters and in second group L. acidophilus, B. breve was studied as probi otics besides starter culture. Results showed that in both sets, the highest amount of CLA was obtained by addition of 2 % non-fat dry milk, the addition of safflower oil ( 1.4 ml/l milk) in pH=6.0, incubation temperature of 37 ̊C, and term ination of incubation at pH=4.5. In the most suitab le condition‚ the amount of CLA in probiotic yoghurt c ontaining B. lactis increased by 450% from an avera g of 0.04 mg/ml in non-treated yoghurt to 0.22 mg/ml fat in t he probiotic yoghurt containing safflower oil. But in the case of B. breve, the content of produced CLA was increased 10 fold from 0.04 to 0.4 mg/ml. Anyway, the viabil ty of L. breve was less than L. acidophilus by 2 log CFU/ml. So for further investigation encapsulation of B. b reve is suggested to reach to a product with the high amoun t f CLA and enough viable cells. No significant di fference between product and control was observed in the ran king sensory test.