双孢菇远红外干燥过程中内部水分的变化规律

利用低场核磁共振技术分析远红外干燥双孢菇内部水分分布及变化规律，研究在50、60、70 ℃条件下，切片厚度为3、5、7 mm双孢菇切片干燥过程中内部水分变化。结果表明：双孢菇中主要存在自由水、弱结合水和结合水3 种状态水，其中切片厚度为3、5、7 mm双孢菇片自由水含量（M23值）分别为9 048.26、12 038.71、17 532.27，在3 种状态水中所占比例最大。在相同干燥温度条件下，切片厚度为3 mm的双孢菇自由水和弱结合水去除所需的时间最短；随着干燥温度的升高，3、5、7 mm双孢菇片中自由水和弱结合水含量逐渐降低。3 种切片厚度的双孢菇在不同温度干燥过程中结合水含量无明显下降趋势，说明干燥过程中脱去的主要是自由水和部分弱结合水，结合水基本不会去除，因此结合水含量对双孢菇远红外干燥效果无明显影响。

Analysis of Moisture Change during Far-Infrared Drying of Agaricus bisporus

The moisture distribution and change of Agaricus bisporus during far-infrared drying was analyzed by lowfield
nuclear magnetic resonance (NMR) technology. Agaricus bisporus slices (3, 5 and 7 mm thickness) were dried at
three different temperatures (50, 60 and 70 ℃). Results showed that the water states in Agaricus bisporus included free
water, immobilized water and bound water. Free water (M23) was the most dominant among the three water states, which
was 9 048.26, 12 038.71 and 17 532.27, respectively, for 3, 5 and 7 mm thick Agaricus bisporus slices. The removal of free
water and immobilized water from 3 mm thick Agaricus bisporus slices was the fastest at the same drying temperature.
The contents of free water and immobilized water in Agaricus bisporus slices were decreased gradually with increasing
temperature, independent of the thickness of slices, while the content of bound water had no obvious downtrend at different
temperatures. These findings indicated that free water and partial immobilized water were mainly removed during the drying
process, and bound water was hardly removed. Thus, the content of bound water had no significant effect on Agaricus
bisporus during far infrared drying.