Abstract: The purpose of this study was to evaluate the physiological characteristics and nutritional quality of corn kernels during the post-ripening stage. Using principal component analysis (PCA), this study analyzed and comprehensively evaluated 14 physiological and quality traits of post-ripening corn kernels from two varieties (Zhengdan 958 and Xianyu 335), including water content and state, respiratory rate, soluble sugar content, α-amylase activity, catalase (CAT) activity, peroxidase (POD) activity, hexokinase (HK) activity, isocitrate dehydrogenase (IDH) activity, fatty acid value, starch content, 1 000-grain mass and rapid digestible starch (RDS) content. The results showed significant variations in various quality traits of corn grains during the post-ripening process (P < 0.05). PCA extracted three principal components, namely storage intolerance factor, yield factor and digestive characteristic factor, which explained 53.436%, 18.466% and 12.857% of the total variance, respectively, 84.759% in total. The post-ripening quality and time of corn could be determined according to the changes of F-value. The post-ripening time of newly harvested corn grains from Zhengdan 958 and Xianyu 335 were 50 and 30 days, respectively. The results of this study could provide a reference for the evaluation of the post-ripening quality of newly harvested corn and the processing and utilization of corn.

Key words: corn; post-ripening; quality traits; principal component analysis; comprehensive evaluation