基于Weibull分布函数的双孢菇热泵干燥特性研究

为提升双孢菇干制品品质,采用热泵式冷风干燥对双孢菇进行脱水处理,以双孢菇热风干燥和冷冻干燥为参照实验,对不同热泵式冷风干燥条件下(进口风速、干燥温度)双孢菇的干燥耗时、干燥能耗、产品硬度以及产品白度进行研究;利用Weibull分布函数对双孢菇热泵式冷风干燥过程中的水分扩散机制进行分析;基于干燥效率指标和产品品质指标,采用加权综合评分法对双孢菇热泵式冷风干燥过程进行评价。实验表明:加快进口风速干燥耗时最小值比最大值降低9.09%,提升干燥温度干燥耗时最小值比最大值降低27.27%;干燥温度对双孢菇热泵式冷风干燥能耗、产品硬度和产品白度影响更为显著(p<0.05);Weibull分布函数能够准确描述(R2>0.99)双孢菇热泵式冷风干燥过程,不同干燥条件下双孢菇冷风干燥的形状参数均小于1,整个干燥主要受内部水分扩散控制;相对于冷冻干燥,双孢菇热泵式冷风干燥耗时及能耗分别降低了50%和26.35%;而相对于热风干燥,冷风干燥技术将双孢菇干制品的产品硬度降低13.44%,同时干制品产品白度提升了59.92%;实验操作条件范围,双孢菇冷风干燥最佳干燥条件为25 ℃干燥温度和2 m/s进口风速。结论:热泵式冷风干燥技术能够提升双孢菇干制品品质同时降低干燥耗时和能耗。

Heat Pump Drying Characteristics of Agaricus bisporus Based on Weibull Distribution Function

In order to improve the quality of dried products of Agaricus bisporus, heat pump cold air drying was used in it's dehydrate process, the hot air drying and freeze drying of Agaricus bisporus were used as controlled experiments. The drying time, energy consumption, product hardness and product whiteness were determined during all drying processes. Meanwhile, the Weibull distribution function was used to analysis the diffusion mechanism of Agaricus bisporus during heat pump cooling air drying. The weight comprehensive evaluation of Agaricus bisporus was carried out based on the indexes of drying efficiency and product quality. Results showed that, when the inlet air velocity was accelerated and drying temperature was raised, the minimum time of Agaricus bisporus cold air drying time were 9.09% and 27.27% lower than the maximum respectively. Drying temperature had a more significant effect on the time consumption, energy consumption, product hardness and product whiteness of Agaricus bisporus (p<0.05). Weibull distribution function could accurately (R2>0.99) describe the heat pump cold air drying process of Agaricus bisporus. Under different drying conditions, the shape parameters of cold drying of Agaricus bisporus were all less than 1, and the whole drying was mainly controlled by internal water diffusion.Compared with freeze-drying, the drying time and energy consumption of Agaricus bisporus cold air drying decreased to 50% and 26.35% respectively. Compared with hot air drying, cold air drying technology reduced the hardness of dried products of Agaricus bisporus by 13.44%, while the whiteness of dried products increased by 59.92%. The optimum drying conditions for the cold air drying of Agaricus bisporus were 25℃ and 2 m/s inlet air velocity. Conclusion:Heat pump cold air drying technology could improve the quality of dried products of Agaricus bisporus and reduce drying time and energy consumption at the same time.