远红外辐射温度对金银花干燥特性及品质的影响

摘要

为探讨远红外辐射温度对金银花干燥特性、微观结构、有效成分及产品色泽的影响,采用远红外辐射干燥设备,对金银花进行远红外辐射干燥实验研究.结果表明:在金银花远红外辐射干燥过程中,提高辐射温度能够显著提高干燥速率和缩短干燥时间;金银花远红外辐射干燥过程为内部扩散控制;有效水分扩散系数范围为1.13×10-10～4.57×10-10 m2/s,其值随着辐射温度的升高而极显著增加(P＜0.01);提高辐射温度能够在金银花组织结构中生成更多、更大的微孔道,从而促进水分扩散;随着辐射温度的升高,金银花中绿原酸、木犀草苷、马钱苷等功效成分含量均呈先升高后降低的趋势,L*值先升高后降低,a*值和△E值先降低后升高;在其他干燥参数固定的条件下,辐射温度为240℃时,可以在实现较快干燥速率的同时获得良好的产品品质.%The aim of this study was to investigate the effect of radiation temperature during far-infrared radiation drying on drying characteristics,microstructure,nutrient components and color of Flos Lonicerae.Drying of Flos Lonicerae was carried out with a far-infrared radiation dryer.The results showed that the increase in radiation temperature could significantly improve the drying rate and shorten the drying time.Only the falling-rate period appeared during the drying process,suggesting that far-infrared radiation drying of Flos Lonicerae is controlled by internal diffusion.The values of effective moisture diffusivity ranged from 1.13 × 10-10 to 4.57 × 10-10 m2/s,which increased with radiation temperature.The increase in radiation temperature could result in the formation of more micro-runnels of larger size in the structure of dried Flos Lonicerae,which is beneficial to moisture diffusion during the drying process.With increasing radiation temperature,the contents of chlorogenic acid,luteoloside and loganin showed an initial increase followed by a decline.The L* value increased first and then decreased,and the opposite trend was observed for a* and △E values.At a radiation temperature of 240 ℃,both high drying rate and a good quality product could be achieved by fixing other drying parameters in this study.