Abstract: By adding different levels of sodium carboxymethyl cellulose（CMC-Na）and different thickeners to flavor fermented milk and collecting commercial flavor fermented milk with different thickeners,the fat in each sample was determined by the third method（alkali hydrolysis method）of GB 5009.6—2016. The effect of CMC-Na on the determination of fat in flavor fermented milk was deeply analyzed. The results showed that the addition of 0.10 % and 0.25 % CMC-Na had no effect on the fat determination results,but from the addition of 0.50%,the higher the addition level of CMC-Na,the lower the fat determination results. At the level of 1%,9 thickeners which are widely used in the market were compared with CMC-Na. Among them,pectin,hydroxypropyl starch phosphate,agar,acetylated starch diphosphate,gelatin,carrageenan and sodium alginate had no effect on the determination of fat in fermented milk,but gellan gum and xanthan gum were similar to CMC-Na. It will make the fat detection results lower in the fermented milk. The fat of 20 commercial flavor fermented milk was determined. The fat test results of two products containing CMC-Na were quite different from the marked value and lower than the product standard requirements. The fat test results of other flavor fermented milk without CMC-Na were close to the label value. This provides a certain reference for the accurate determination of fat in flavor fermented milk and the diversified development of products.

Key words: sodium carboxymethyl cellulose （CMC-Na）, flavor fermented milk, fat