超声、红外耦合热风干制可得然胶传质模型构建及品质分析

Mass Transfer Study on Drying of Curdlan by Hot Air Coupled with Ultrasound and Infrared Irradiation and Quality Analysis

目的:采用超声、红外耦合热风干制可得然胶,探究多物理场下可得然胶干制机制和品质变化,开发可得然胶绿色干制技术。方法:以可得然胶湿胶为材料,采用单独热风、超声耦合热风、单独红外、红外耦合热风四种技术干制可得然胶,构建含温度变化的传质模型,分析理化品质。结果:单独热风干制可得然胶需40 min,超声耦合热风干制、单独红外干制以及红外耦合热风干制的时间分别缩短至36、26、22 min。构建耦合温度变化的传质模型可较准确预测干制过程中可得然胶内部水分变化,红外耦合热风处理下可得然胶内部水分扩散系数范围为9.79×10^(-9)~9.81×10^(-9) m^(2)/s,表面传质系数为4.69×10^(-2) kg water/(m^(2)·s),均高于其他处理组,其次为单独红外干制、超声耦合热风干制、单独热风干制。四种方法干制的可得然胶凝胶强度、葡萄糖含量、表面化学功能团、晶体结构、热稳定性接近。结论:综合考虑可得然胶干制效率、品质,与单独热风和超声耦合热风相比,红外干制是一种高效的可得然胶干制方法。

Objective:Hot air coupled with ultrasound and infrared irradiation were used for the drying of curdlan.The drying mechanism and quality change of curdlan were explored under the multi-physical fields,so as to developing the green drying technology of curdlan.Methods:Forced convective hot air alone,ultrasound-coupled forced convective hot air,infrared irradiation alone,and infrared-coupled forced convective hot air were used to dry curdlan.A mass transfer model considering temeprature change was constructed and the quality of the dried curdlan was comprehensively assessed.Results:Under the studied forced convective hot air drying conditions,it took around 40 min to dry the curdlan,and the required drying time was reduced to 36,26 and 22 min for ultrasound-coupled hot air drying,infrared irradiation alone drying,and infrared-coupled hot air drying,respectively.The moisture transfer model coupled with the temperature change was able to accurately predict the change of the moisture content throughout drying.Under infrared drying coupled with convective hot air,the range of moisture effective diffusivity inside curdlan was 9.79×10^(-9) to 9.81×10^(-9) m^(2)/s,and the surface mass transfer coefficient was 4.69×10^(-2) kg water/(m^(2)·s),which were higher than those of the other treatment groups,followed by those under infrared irradiation alone drying,ultrasonic-coupled hot air drying,and hot air drying alone.Moreover,the gel strength,glucose content,the distribution of chemical functional groups on surface,crystal structure and thermal stability of curdlan samples dried by different methods were all similar.Conclusion:Taking all these results into consideration,infrared drying was regarded as an efficient method for drying curdlan compared to hot air drying and ultrasound-coupled hot air drying.