Abstract: Changes in the contents of 3 free sugars and 18 free amino acids in two table corn cultivars (Jingtian 5 sweet corn and Jingnuo 8 waxy corn) during development from pollination after silking to milky maturation were determined using high performance liquid chromatography (HPLC). The contents of sucrose and alanine, as well as total sugars and total amino acids in both cultivars showed low-high-low trends with development time. Principle component analysis (PCA) and cluster analysis (CA) were applied to analyze the changes of these 21 compounds in the two cultivars at different developmental stages. Three PCs were extracted which explained 39.9%, 24.4%, and 13.3% of the total variance, respectively. Sweet amino acids and sugars presented high loadings on PC1 and PC2, illustrating that PC1 and PC2 are responsible to the sweet related informations. In addition, PC3 most correlated with the umami taste amino acids, aspartic acid and glutamic acid, and the samples from the different cultivars were separated on PC3. Moreover, CA showed that the samples were clustered into groups according to similar developmental stages. In conclusion, the PCA and CA performed on free amino acids and sugars clearly allowed to discriminate the developmental stages, and the cultivars to a lesser extent. These results would provide a practical reference for quality control of processed table corn products especially for corn juice flavor enhancement.

Key words: free sugars; free amino acids; table corn; developmental stages; flavor