Optimization of the processing parameters of shiitake (Lentinus edodes) crisps during heat pump coupled with instant controlled pressure drop puffing drying process

Objective: The objective of this study was to develop high-quality non-fried whole shiitake (Lentinus edodes) crisps due to having high oil content of vacuum fried L. edodes crisps which inevitably pose health risks after long-term use. Methods: Based on uniform design, instant controlled pressure drop (DIC) was used to investigate the influences of moisture content after heat pump pre-drying, puffing temperature and vacuum drying temperature on the puffing degree, rehydration ratio, total color difference, hardness and crispness of L. edodes crisps. The polynomial regression model was established by using a weighted comprehensive score method, and it was optimized and verified accordingly. Results: The optimum parameter combinations of L. crisps during DIC processing were moisture content after heat pump pre-drying of 35.63%, puffing temperature of 100 ℃, vacuum drying temperature of 64.17 ℃. Under the control of these optimal parameter combinations, the puffing degree of L. crisps was 69.34%, total color difference was 20.68, hardness was 108.16 N, and crispness was 75.79. Conclusion: Uniform design combined with response surface methodology can be used to optimize processing parameters of DIC crisps and obtain high quality non-fried L. crisps.