干燥温度对铁皮石斛颗粒中多糖溶出特性的影响

Effects of Drying Temperature on the Dissolving-out Properties of Polysaccharides in Dendrobium officinale Particles

摘要:

本研究旨在探明干燥温度对铁皮石斛颗粒多糖溶出率和溶出速度的影响及其机理。以新鲜铁皮石斛颗粒（直径5 mm×长5 mm）为原料，通过60~140 ℃热风干燥制备干燥铁皮石斛颗粒，于60 ℃水浴锅上进行铁皮石斛颗粒的多糖浸提，同时比较新鲜和干燥铁皮石斛颗粒的组织结构。新鲜铁皮石斛颗粒的多糖溶出率和多糖扩散系数分别为（46.65±0.86）%、1.02×10-2 mm2/h。在60~100 ℃的干燥温度范围内，干燥促进了铁皮石斛颗粒中多糖的溶出，干燥温度越低，对多糖溶出的促进作用越大。60 ℃干燥铁皮石斛颗粒的多糖溶出率和多糖扩散系数分别高达（64.54±1.27）%和1.94×10-2 mm2/h。较低的干燥温度有利于铁皮石斛颗粒保持组织结构，减少材料收缩，减轻美拉德反应和焦糖化反应，同时产生一定的内部空隙，从而促进其多糖的溶出。本研究为铁皮石斛的干燥加工和利用提供了技术数据和理论依据。

Abstract:

The objective of this work was to evaluate the effect of drying temperature on the dissolving-out ratio and the dissolving-out velocity of polysaccharides in D. officinal particles. The fresh D. officinal particles (5 mm in diameter×5 mm in length) as the raw material was used to prepare the dried D. officinal particles by hot-air-drying at different temperatures with the range of 60 to 140 ℃.Polysaccharides in the dried D. officinal particles were extracted by hot-water soaking at 60 ℃.The tissue structures of fresh and dried D. officinal particles were compared. The polysaccharide dissolving-out ratio and diffusion coefficient of fresh D. officinale particles were (46.65±0.86)% and 1.02×10-2 mm2/h, respectively. In the drying temperature range of 60 to 100 ℃, the dissolving-out of polysaccharides in dried D. officinale particles was promoted by drying. Low temperature is beneficial to the dissolving-out of polysaccharides. The polysaccharide dissolving-out ratio and diffusion coefficient of dried D. officinale particles prepared at 60 ℃ reached (64.54±1.27)% and 1.94×10-2 mm2/h, respectively. The low drying temperature was beneficial for D. officinale particles to maintaining the tissue structure, reducing shrinkage, mitigating Maillard reaction and caramelizing reaction, and producing certain internal voids, which promoted the dissolving-out of polysaccharides. This work provided technical data and theoretical basis for the drying and utilization of D. officinale.