桃片超声渗透-红外辐射干燥特性及能耗研究

Drying Characteristics and Energy Consumption of Peach Slices during Ultrasound-assisted Osmotic Dehydration in Combination with Infrared Radiation

超声波的空化效应可提高渗透过程中传质效率。为研究桃片超声渗透-红外辐射干燥特性及干燥能耗,进行了超声渗透后红外60、70、80℃干燥试验,得到干燥特性曲线,建立干燥动力学模型;同时,对干燥过程的能耗进行了分析。结果表明:超声可增加桃片渗透脱水速率和固形物渗入率,超声渗透时间选择30 min(T_1)及60 min(T_2)为宜;Verma et al.模型较好拟合了桃片超声渗透-红外辐射干燥规律,未经渗透、T_1及T_2渗透处理桃片在60、70、80℃干燥条件下水分有效扩散系数分别为8.8789×10^(-9)~1.3011×10^(-8)、7.1213×10^(-9)~1.0393×10^(-8)、6.6771×10^(-9)~8.7785×10^(-9) m^2·s~(-1~;随着温度升高,干燥所需能耗降低;经超声渗透脱水后,干燥所需能耗增加。不同条件下,干燥能耗均在干基水分含量0.3左右急剧增加,可作为水分转换点,利用其它干燥方式,如变温压差膨化干燥,达到节约能耗、提高产品品质的目的。试验结果为桃片红外辐射干燥工艺参数优化及开发新型果蔬脆片提供参考。

The cavitation effect of ultrasonic waves can improve the efficiency of mass transfer in the process of osmotic dehydration. In order to study the drying characteristics and energy consumption of peach slices during ultrasound-assisted osmotic dehydration in combination with infrared radiation, drying experiments after ultrasound-assisted osmotic dehydration were carried out at 60, 70, and 80, respectively; the drying curves were obtained, and the mathematical models for the drying kinetics were established. Meanwhile, the energy consumption during the drying process was analyzed. The results showed that ultrasound-assisted osmotic dehydration could improve the ratio of water loss and solid gain. The appropriate ultrasound-assisted osmotic times were set at 30 min (T1) and 60 min (T2), and the Verma et al. model was found to be suitable to describe the drying characteristics of peach slices during the ultrasound-assisted osmotic dehydration and infrared radiation. The effective moisture diffusivity values of non-treated, T1and T2treated peach slices at 60, 70, and 80 were in the ranges of 8.8789 × 10-9~1.3011 × 10-8m2·s-1, 7.1213 × 10-9~1.0393 × 10-8m2·s-1, and 6.6771 × 10-9~8.7785 × 10-9m2·s-1, respectively. With the increase in temperature, energy consumption reduced but increased after ultrasound-assisted osmotic dehydration. Under different treatments, energy consumption increased rapidly with a moisture content of about 0.3 (dry basis), which can be a moisture conversion point to use other drying methods, such as explosion puffing drying at varied temperatures and pressures, to reduce energy consumption and improve product quality. This study provides a reference for the parameter optimization in the infrared drying of peach slices and the development of new fruit slices. © 2015, Editorial Board of Modern Food Science and Technology. All right reserved.