Abstract:The microwave vacuum puffing technique for standard jujube slices was optimized through singlefactor and response surface methodologies，and the effects of three different processing methods—microwave vacuum puffing，low-temperature vacuum frying，and traditional sun-drying method—on the content of bioactive substances and antioxidant activity of substandard jujubes were investigated. With substandard Ruoqiang gray jujubes from Xinjiang as materials，the total sugar content was measured by the phenol-sulfuric acid method；total phenols content were measured by the Folin-Ciocalteu method；total flavonoids content were determined by the NaNO2-Al（NO3）3 method；and total triterpenic acids content were measured by colorimetry.The antioxidant activity of substandard jujubes processed by the above three methods was evaluated according to the DPPH radical scavenging capacity，ABTS+radical scavenging capacity，total reducing power，and hydroxyl radical scavenging capacity.The results indicated that the optimal processing conditions for substandard jujube slices included a puffing power of 520 W，a puffing time of 17 min，and a vacuum time of 15 min. Under these conditions，the total phenol content and total flavonoids content of substandard jujube slices was significantly higher than that of low-temperature vacuum frying and traditionally sun-dried ones；the triterpenic acids content was significantly higher than that of low-temperature vacuum frying and traditionally sun-dried ones. Moreover，the antioxidant activity of the microwave vacuum-puffed substandard jujube slices was higher than that of low-temperature vacuum fryingand traditionally sun-dried ones.