鲜食糯玉米品种热力学特性评价

热力学特性是评价鲜食糯玉米子粒均匀性、热稳定性和回生程度的重要指标。为了解我国鲜食糯玉米品种热力学特性，利用差示扫描量热法(DSC)测定104个鲜食糯玉米品种的热力学特性，并采用主成分分析方法对其结果进行评价。结果表明，鲜食糯玉米104个品种间淀粉热力学特征参数有显著差异，且不同参数中以回生值变异最大，回生样品的终值温度变异最小。相关分析表明，糯玉米淀粉胶凝特征参数起始温度、峰值温度、终值温度两两极显著正相关，糊化范围与峰值指数呈极显著负相关，回生热焓值和回生值呈极显著正相关。将热力学特征参数可简化为4个主成分，累计方差贡献率为86.11%。104个糯玉米品种可分为8大类，其中I和II类分别有53和43个品种，共占供试材料的92.3%，是最主要的两种类型。糯玉米淀粉热力学特征值间有良好的相关性，影响鲜食糯玉米子粒品质最重要的热力学特征值为回生值、热焓值和胶凝温度。

Evaluation on Thermal Properties of Fresh Waxy Maize Varieties

Thermal property is a significant index to evaluate the uniformity,thermal stability and retrogradation of fresh waxy maize.In order to understand the thermal characteristics of Chinese fresh waxy maize varieties,the thermal characteristics of 104 fresh waxy maize varieties were measured by differential scanning calorimetry (DSC),and the results were evaluated by principal component analysis.The results indicated that the thermal characteristics were significantly different among the 104 waxy maize varieties,and the variation coefficients were the highest for the retrogradation percentage and the lowest for the conclusion temperature of retrograde samples.The correlation analysis showed that onset,peak,and conclusion temperatures of gelatinization were positively correlated each other,gelatinization range was negatively correlated to peak height index,and retrogradation percentage was positively correlated to retrogradation enthalpy.Those characteristics could be simplified to four principal components,with the cumulative variance contribution rate was 86.11%.The 104 waxy maize varieties could be divided into eight categories with different specificities.Among those categories,there are 53 and 43 varieties in Categories I and II respectively,both are two main types and occupied 92.3% of all the samples.There is a good correlation between the thermal characteristics,and the retrogradation percentage,gelatinization enthalpy,and gelatinization temperatures are the three most important characteristics that affect the grain quality of fresh waxy maize.