洋槐蜜和椴树蜜结晶前后的主要物质组成和热力学性质变化研究

为实现对不同类型蜂蜜的特征和质量的科学评价，测定了不同蜜源(洋槐蜜和椴树蜜)和不同结晶状态蜂蜜的主要成分，并利用差示扫描量热技术分析了其热力学性质。结果表明：无论结晶与否，不同蜜源蜂蜜中的葡萄糖和果糖含量均差异显著。相对于椴树蜜样品，洋槐蜜样品的水分活度可能更不利于酵母菌的滋生。玻璃转化温度、放热峰峰温和放热峰焓变等热力学参数，对于区分不同的蜂蜜样品较为灵敏。蜂蜜样品的热力学性质主要受到结晶状态的影响，而与蜜源特征相关性较小。基于以上结果，及时监测蜂蜜的水分活度有助于控制微生物(尤其是酵母菌)的滋生。通过测定蜂蜜的玻璃转化温度、放热峰峰温和放热峰焓变等指标，可以预测蜂蜜的结晶程度。

Changing Patterns of Composition and Thermodynamic Property of locust and linden honey after crystallization

To establish a practical method for evaluating the characteristics and quality of honeys, this paper analyzed the compositions of honeys from different nectar plants （Tilia tuan and Robinia pseudoacacia）in different physical states (amorphous or crystalline), and determined the thermodynamic properties of different honeys by differential scanning calorimetry (DSC). The results showed that: Glucose and fructose contents between Tilia tuan honey and Robinia pseudoacacia honey, at either crystalline or amorphous states, were significantly different. The water activity of Tilia tuan honey samples was more favorable to yeast growth, compared with that of Robinia pseudoacacia honey. The glass transition temperature (Tg), endothermic peak temperature (Tpk) and endothermic peak enthalpy change (ΔH) could be used to effectively evaluate the crystallization degree of honeys. The thermodynamic properties of honey were significantly affected by its physical state (amorphous or crystalline), rather than its nectar plant of origin. Overall, the growth of microorganisms, especially yeast, in honey could be controlled by monitoring the water activity of honey. Thermodynamic parameters including Tg, Tpk and ΔH could be employed to determine the degree of crystallization of a specific honey.