The Diversity of Amino Acids, Sugars, Organic Acids and Phenolic Compounds in Four Cultivars of Allium cepa L.

The diversity of cultivars of Allium cepa L results in varying chemical compositions influenced by genetic and environmental factors. This study aimed to compare the chemical composition of four cultivars of onion (Allium cepa L.), namely orange onion (HYR), white onion (HYW), Myanmar red onion (HKM) and Indian red onion (HKI), by analyzing amino acids, sugars, organic acids, phenolic compounds, flavonoids and antioxidant activities using chemical methods combined with multiple statistical analysis (PCA, HCA and VIP score).The results showed that HYR contained the highest total amino acids (5477.39 µg/100g DW) while HYR contained a prominent amount of arginine (2414.45µg/100g DW) and HYW has a high content of umami-related amino acids such as glutamic acid and glutamine. In terms of sugar, HKI had the highest total content (340.26 mg/g DW), while HYR was predominantly glucose and fructose. HKM had the highest fructooligosaccharide (14.53 mg/g DW), while HYW had the highest total organic acids (64.44 mg/g DW), predominantly malic acid and citric acid, while HKI had the highest vanillic acid (305.22 mg/100 g DW), rutin, and myricetin. HKI also showed the highest TPC, TFC, DPPH, and FRAP values ​​(11.56 mg GAE/100g DW, 9.09 mgRE/100g DW, 59.70 mgTE /100gDW, and 72.13 mg/100g DW, respectively), while HYW had the lowest values ​​in all variables. VIP score analysis indicated that essential compounds such as glutamic acid, myricetin, vanillic acid, and glucose are the main variables in classifying the species, displaying the biodiversity that can be used to select suitable cultivars for the development of food products