A Comparative Study on the Nutrients, Mineral Elements, and Antioxidant Compounds in Different Types of Cruciferous Vegetables

Studies on the diversity within and among cabbage (Brassica oleracea L. var. capitata L.), cauliflower (Brassica oleracea var. botrytis), and Chinese cabbage (Brassica rapa L. ssp. pekinensis) variants are essential for the development of healthy diets. However, most studies on them have been limited to a single species, with little integrated analysis between them. In this study, the diversity within and among these species and varieties is assessed by determining the contents of 15 major characteristic nutrients, antioxidants, and minerals in 12 varieties of cabbage, 9 varieties of cauliflower, and 12 varieties of Chinese cabbage cultivated under the same conditions. The results show that there are significant differences in the compositional distributions of cabbage, cauliflower, and Chinese cabbage. Cabbage has the highest contents of soluble sugars (27.73 mg·kg−1 FW), flavonoids (5.90 mg·g−1 FW), and Fe (46.90 mg·kg−1 DW). Cauliflower is an ideal source of soluble protein (603.04 mg·kg−1 FW), polyphenols (1.53 mg·g−1 FW), glucosinolates (25.27 μmol·g−1 FW), and Cu (4.25 mg·kg−1 DW). Chinese cabbage is rich in vitamin C (0.45 mg·g−1 FW) and minerals (K, Ca, Mg, P, Mn, and Zn, at 9206.67 mg·kg−1 DW, 3297.00 mg·kg−1 DW, 3322.79 mg·kg−1 DW, 5614.78 mg·kg−1 DW, 15.36 mg·kg−1 DW, and 21.87 mg·kg−1 DW, respectively). There is a correlation between the quality, antioxidant properties, and minerals of the three species. In principal component analysis, a wide distribution of cabbage varieties and a high degree of overlap with the confidence ellipse of cauliflower are observed, indicating that certain cabbage varieties share compositional characteristics with cauliflower. These findings provide a reference for selecting varieties with higher nutritional value and antioxidant properties, as well as breeding new varieties.