Analysis of Nutritional Quality in Taste-Type (‘Baiyu’) and Conventional (‘Qinhongbao’ and ‘Jinbao’) Onions (Allium cepa L.)

This study aims to systematically compare the key nutritional and flavor characteristics of three distinct onion materials: the novel taste-type cultivar ‘Baiyu’, the pink-skinned cultivar ‘Qinhongbao’, and the conventional yellow-skinned cultivar ‘Jinbao’. By measuring and statistically analyzing their agronomic traits, mineral content, amino acids, fatty acids, sugar composition, and organic acids, we found that ‘Baiyu’ exhibits a superior nutritional profile compared to the conventional varieties. Its total sugar content was 41.29 mg/g, with fructose (14.88 mg/g) as a major contributor to its pronounced sweetness. The total organic acid content was 8053.28 μg/g, with a distinct profile dominated by lactic acid (39.4%), followed by propionic and malic acids. The total amino acid content reached 1757.49 μg/g, characterized by notably high levels of arginine and glutamic acid. Fatty acid analysis revealed a linoleic acid content of 26.39 μg/g. Regarding mineral elements, ‘Baiyu’ exhibited the highest contents of potassium (1744.53 mg/100 g) and magnesium (523.50 mg/100 g), which were significantly higher than those in the pink onion but showed no significant difference compared to the yellow onion. In conclusion, the taste-type onion ‘Baiyu’ exhibits comprehensive quality advantages in terms of the co-elevated levels of both sugars and organic acids. This revision ensures that our conclusions are fully supported by the data presented, flavor-related amino acids, beneficial fatty acids, and key mineral content, which offers valuable insights and a scientific basis for flavor-oriented onion breeding and the development of functional onion products.