Lactobacillus acidophilus as a dietary adjunct in dahi and yogurt

Abstract

An experiment was conducted to study the beneficial effect of incorporating L. acidophilus in dahi and yogurt as a dietary adjunct. An attempt was also made to find out the bile tolerance of L. acidophilus and other lactic acid bacteria. An exhaustive review of literature has been presented on the issues of lactose intolerance and hypercholesteremia and the beneficial effects of lactic acid bacteria in alleviating these drawbacks, with a special emphasis on bile tolerance and intestinal colonisation. The methods of analysis of some important components of dahi and yogurt have been detailed. Treatment dahi was prepared by inoculation with L. acidophilus in addition to normal dahi cultures. This was compared with control dahi prepared with normal cultures alone. Treatment yogurt was prepared with inoculating L. acidophilus alongw ith normal yogurt cultures. This wascompared with control yogurt prepared using normal yogurt cultures. The samples were then analysed for various parameters. There was an increase in the p-galactosidase specific activity of treatment dahi when compared to the control dahi. But m the case of yogurt, the treatment yogurt was having a low 3-galactosidase specific activity when compared to the control yogurt. Control dahi showed inhibition against E. aerogenous, M. falvous, E. coli and S. aureus. It did not showed any inhibition against B. cereus. Treatment dahi exerted a significantly high inhibition zone against all the test organisms m comparison to control dahi. Control yogurt inhibited only E. aeroqenous and E. coli. Treatment yogurt exerted a significantly high antibacterial activity against all the organisms tested. Of, all the lactic acid bacteria tested for their ability to grow in the presence of 0.3 per cent of Oxgall, only L. acidophilus grew satisfactorily. L. delbruecii ssp bulgancus showed a poor growth, whereas S. salivanus ssp thermophilus Lac. lactis and Lac, lactis ssp diacetylactis failed to grow in the presence of Oxgall. Both the dahi and yogurt treatments showed higher hypocholesteremia when compared to their respective controls. The total serum cholesterol level, serum triglyceride, LDL- Cholesterol and cardiac risk factor of the treatment groups were significantly lower than the respective controls. The HDL-Cholesterol was high m both the treatments when compared to the respective controls. The growth rate of treatment dahi group was low when compared to the control dahi group. But the treatment yogurt group showed a higher growth rate as compared to the rats fed on control yogurt.