非酶褐变直接影响铁棍山药片干燥品质。表面温度和水分特性是影响干燥过程非酶褐变的两个重要因素，但其定量关系以及对非酶褐变的影响机理还不清楚。 本项目将采用红外热成像技术量化铁棍山药片远红外热泵干燥过程中表面水分和温度分布，并建立与褐变度的数学关系，确定发生非酶褐变的临界含水率。通过现代谱学仪器及化学手段确定参与非酶褐变的主要物质，进而建立其与表面温度和含水率之间作用的定量关系。利用低场核磁共振技术对水分分布状态和迁移行为进行分析，从宏观和微观两个层面，阐明表面温度和水分特性对铁棍山药片远红外热泵干燥过程非酶褐变的影响机制。确定生产中以褐变度为依据的干燥终点判定方法，为优化防褐变干燥工艺提供科学依据。有望从根本上控制铁棍山药片干燥过程非酶褐变的发生，为人们提供安全的高品质食品。

Non-enzymatic browning reaction during drying process can directly impact the quality of iron bars Chinese yam chip. Surface temperature and moisture characteristics are two important factors affect the extent of the reaction, however, it is unclear that the quantitative relationship between them as well as the effect mechanism on non-enzymatic browning. This project is proposed to 1) quantify the surface moisture and temperature distribution of iron bars Chinese yam chips dried by far infrared heat pump system using infrared thermal imaging, establish the mathematical relationship between surface temperature and moisture distribution and browning degree and determine the critical moisture content for browning reaction. 2) analyze the main reactants of non-enzymatic browning through modern spectroscopy instruments and chemical methods, find the quantitative relationship between the reactant changes and the surface temperature and moisture content of yam. 3) investigate the distribution and migration behavior of moisture molecule in different states using low-field nuclear magnetic resonance technology. Consequently, clarify the impact mechanism of non-enzymatic browning by surface temperature and moisture change characteristic of iron bars Chinese yam chips during far infrared heat pump drying process from both of the macroscopic and microscopic aspects. The results may help to accurately determine the drying-end point based on the degree of browning in the actual production and provide more scientific information to further research anti-browning drying technology, control the extent of non-enzymatic browning of iron bars Chinese yam chips during drying process radically, and furnish safe and high-quality food.