Abstract: The contents of 3 free sugars and 18 free amino acids in two fresh-edible corn cultivars (Jingtian-5 and Jingnuo-8, belongs to sweet corn and waxy corn, respectively) were determined during development using HPLC. The study conducted from the blister stage to milk stage. The contents of sucrose and ALA in both cultivars showed low-high-low curves with developing time prolonged, as well as the contents of total sugar and total amino acids. Principle component analysis (PCA) and cluster analysis were applied to analyze the changes of these 21 compounds in the two cultivars at varies developing stages. Three PCs were extracted and 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 the samples close to each other with near developing stages. In addition, PC3 most correlated with the umami taste amino acids, aspartic acid and glutamic acid, and the sample scores from different cultivar separated on PC3. Moreover, cluster analysis (CA) showed that the samples clustered as groups according to similar development stages. In conclusion, the PCA and CA performed on free amino and sugars allowed to discriminate developing stages clearly, and cultivar difference to a lesser extent. Results would provide practical reference to fresh corn processing especially for juice flavor enhancement.

Key words: 游离糖, 游离氨基酸, 鲜食玉米, 发育期, 风味