响应面法优化火龙果真空冷冻干燥工艺

目的：提高火龙果冻干品酥脆度。方法：以美龙1号红肉火龙果为研究对象，通过pearson分析选出与感官评价相关性最高的多孔率为检测指标，考察切片厚度、预冻时间、干燥气压和干燥时间对火龙果冻干品品质的影响，并采用Box-Behnken响应面分析法优化火龙果真空冷冻干燥工艺。结果：切片厚度、预冻时间和干燥时间与火龙果冻干品的多孔率线性相关显著；最佳工艺条件为切片厚度7 mm、预冻时间30 h、干燥气压43 Pa、干燥时间40 h，此工艺生产的火龙果冻干品多孔率最高、表面平整、口感酥脆、颜色均匀鲜艳。结论：利用响应面法改进切片厚度、预冻时间、干燥气压和干燥时间工艺参数可以提高火龙果冻干品品质。

Optimization of vacuum freeze-drying of pitaya by response surface methodology

Objective: Improve the brittleness and crisp of freeze-drying of pitaya. Methods: Taking red pitaya Meilong No.1 as the research object, the porosity was selected as the evaluation index by pearson correlation between sensory evaluation and objective indexes, the effects of slice thickness, pre-freezing time, drying air pressure and drying time on the quality of vacuum freeze-dried pitaya was studied by single factor experiments, and the optimal level was selected; The processing conditions were optimized using Box-Behnken response surface methodology. Results: Slice thickness, pre-freezing time and drying time were linearly correlated with the porosity of freeze-dried pitaya; The optimal process were slice thickness of 7 mm, pre-freezing time of 30 h, drying pressure of 43 Pa and drying time of 40 h, the freeze-dried pitaya produced by this process has the highest porosity, smooth surface, crisp taste and bright and uniform colour. Conclusion: The quality of freeze-drying of pitaya can be improved by using response surface methodology to optimization the slice thickness, pre-freezing time, drying pressure and drying time.