关键词: 蜂蜜, 结晶, 差示扫描量热技术, 水分活度, 热力学特征

Abstract: 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.

Key words: honey, crystallization, differential scanning calorimetry, water activity, thermodynamic property