中晚籼稻谷的品质分析及其米饭加工适应性

QUALITY ANALYSIS AND COOKED RICE MAKING ADAPTABILITY OF LATE INDICA RICE

确定适宜米饭加工用中晚籼稻谷的关联性指标及其阈值区间,进而为米饭主食工业化加工用中晚籼稻的筛选提供参考。以湖北省产115份中晚籼稻谷为研究对象,对其理化特性(长宽比、垩白粒率和垩白度、蛋白质和直链淀粉含量、米汤固形物和碘蓝值及胶稠度)、糊化特性,以及米饭的食味特性进行测定与分析。描述性分析结果显示:在15项稻谷品质指标中,80%的指标的变异系数高于10%,表明所选样品处于不同的品质水平。稻谷理化及糊化特性指标间相关性分析结果表明:长宽比、直链淀粉含量、蛋白质含量、碘蓝值与多数RVA糊化特性指标间均显著相关,而其余4项理化特性指标(垩白粒率、垩白度、固形物、胶稠度)与RVA糊化特性指标间相关性则明显较弱,说明与稻谷理化特性指标中的其他品质指标相比,长宽比、直链淀粉含量、蛋白质、碘蓝值与RVA糊化特性指标间的关系更为密切。米饭食味与稻谷品质指标间相关性分析结果表明:相对于稻谷的其他品质指标,稻米的直链淀粉含量及RVA糊化特性指标与米饭食味的相关性更强,因而更能反映出米饭的食味品质。利用稻谷品质指标与米饭食味特性指标相关系数的绝对值求和法,以及逐步回归分析法,筛选出适应米饭加工的关联性指标为直链淀粉含量及衰减值。采用快速聚类分析法将米饭食味特性分为3个等级,同时依据感官总评分的聚类分析,筛选出适宜米饭加工的稻谷样品,并确定出关联性指标的阈值区间为直链淀粉含量<21%,衰减值≥1 450 mPa·s。

In order to identify the correlation indexes of late indica rice suited for the processing of cooked rice,as well as the threshold interval,and then to provide the reference for selecting of late indica rice suited for the processing of staple food industrialization of cooked rice.The 115 late indica rice in Hubei province were taken and physicochemical characteristics(aspect ratio,chalky kernel percentage and chalkiness degree,protein and amylose content,the solids content and iodine blue value of cooking water,gel consistency),pasting properties of rice and taste characteristics of cooked rice were analyzed.The results of descriptive analysis showed that the coefficients of variation of 80%quality indexes were greater than 10%among the 15 rice quality indexes,which indicated that the rice samples were at different quality levels.The results of correlation analysis between physicochemical characteristics and pasting properties of rice showed that the aspect ratio,amylose content,protein content and iodine blue value were significantly correlated with most RVA pasting property indexes,while the correlations between other physicochemical characteristics(chalky kernel percentage,chalkiness degree,solids content,gel consistency)and RVA pasting property indexes were significantly weaker,which indicated that the relationship between the aspect ratio,amylose content,protein content and iodine blue value and RVA pasting property indexes was closer than other quality indexes in rice physicochemical characteristics.By using the method of summing up the absolute value of the correlation coefficients between rice quality and taste characteristics of cooked rice,as well as the stepwise regression analysis,amylose content and breakdown were selected out for suitability of cooked rice processing.The taste characteristics of cooked rice were classified 3 grades using the method of cluster analysis.Meanwhile,according to the cluster analysis of sensory total score,the rice samples were selected out which were suited for the processing of cooked rice,and the threshold interval of amylose content(<21%),breakdown(≥1 450 mPa·s)were identified.