关键词: 冬枣, 真空冷冻干燥, 响应面分析, 参数优化

Abstract: The effects of three freeze-drying parameters, including winter jujube slice thickness, sublimation drying temperature and desorption drying temperature on vitamin C content in winter jujube after freeze-drying were studied under 200 Pa vacuum condition by conducting 20 experimental runs generated by quadratic generalized rotary regression design to build a regression model between vitamin C content in winter jujube after freeze-drying and the three parameters. The model was subjected to response surface analysis with SAS 9.2 software. The analytical results showed that the optimum freeze-drying conditions for winter jujube were slicing winter jujube to a thickness of 5.5 mm for sublimation drying at －22.1 ℃ and desorption drying at 20.6 ℃. The built model was found to have excellent goodness of fit. Hence, it can provide a reference for practical production.

Key words: winter jujube, vacuum freeze-drying, response surface analysis, optimization