Abstract:The dried roots of Cynanchum auriculatum Royle ex Wight，containing a variety of active components including polysaccharides and total glycosides，have antioxidant and immunomodulatory activities.The C.auriculatum root powder and whole milk powder were used to prepare a yogurt product.The effects of the root powder addition，starter inoculation amount，and fermentation temperature on the quality and total antioxidant capacity（T-AOC）of the product were studied by single factor tests，and the preparation conditions were optimized by orthogonal design.Furthermore，the storage characteristics of the product were studied.The results showed that the yogurt product prepared by fermentation of whole milk powder with 2.0% C.auriculatum root powder，5.0% sucrose，and 0.015 U/kg Y450A starter at 40.0 ℃for 5 h had the T-AOC of 0.129 2 mmol/L，which was higher than that of unfermented product and the product without the addition of C.auriculatum root powder（P<0.05）.Moreover，the product had moderate acidity and sweetness，a good flavor and taste，with isopropanol，2，3-butanedione，n-hexanol，2-heptanone，sec-butyl nitrite，and triethylene glycol monoethyl ether as the main flavor substances.After 9 d of storage at 4 ℃，the T-AOC and viable count of lactic acid bacteria were 0.103 5 mmol/L and 1.57×108 CFU/mL，respectively，and the good sensory quality was maintained.The fermentation with C.auriculatum root powder endowed the yogurt with strong antioxidant capacity and a good flavor and taste.