The objective of this study is replacement fat by inulin and the optimum addition of inulin． The experimental design is that when adding inulin ( 1% ，2% ，3% and 4% ) into skim milk，and mixing different inulin ( 0，1． 5% ，3% and 4． 5% ) and fat ( 4． 5% ，3% ，1． 5% and 0) ． we test titration acidity during the course of the milk fermentation and physical and chemical index and sensory evaluation after cold storage ． Ｒesults showed that add 4% inulin in skim milk and 3% inulin and 1． 5% fat mixture was close to whole milk yogurt at physical and chemical index and sensory evaluation． The result above of this study means inulin could replace fat partly and significantly improve the quality of skim milk yogurt．

The bifidogenic effect of an infant formula supplemented with inulin and fructooligosaccharides (4.0 g/l) was examined clinically and in vitro, and compared that of mature breast milk. In a 28-day clinical study, fecal samples of 21 infants, divided into two groups: one receiving the infant formula and the other breast milk, were microbiologically and biochemically examined.