Abstract: Using response surface methodology optimization method,a novel probiotic yogurt that was fortified with 1.5% inulin and 6% wort was prepared by four strains of lactic acid bacteria fermentation.Compared with the conventional yogurt without supplementation,the activity of lactic acid bacteria in yogurt product is prolonged,the cell viability is enhanced by about 10 times and the yogurt syneresis is reduced by 17.4% during storage,while its sensory characteristics is retained,facilitating the consumers’ acceptance.The chicken feeding experiments proved that the probiotic yogurt can greatly improve the nutrients availability and is beneficial to maintain or to reconstitute the bacterial flora and suppress the pathogen.Therefore,it may be sure that the yogurt is of the healthy function and can be produced industrially.

Key words: cell viability, yogurt, probiotics, inulin, wort