Abstract:To clarify the effects of cultivars, plant parts and low-salt pickling methods on the nutritional quality and heavy metal safety of pickled and dried mustard, three leaf mustard varieties, including narrow-leaf type 'Yongxue 12' (YX), medium-leaf type 'Zhongye Jiutoujie' (ZY), and broad-leaf type 'Caiweiju 1' (CWJ), were used as experimental materials in this study. The contents of basic nutrients, antioxidant compounds, mineral elements, heavy metals, and free amino acids were determined separately in fresh root, stem, and leaf samples as well as in the processed pickled and dried products. The results showed that CWJ had the lowest heavy metal residues, the highest contents of β-carotene and total flavonoids both before and after processing, and the optimal total free amino acids (35.70 mg/g) and essential amino acid proportion (41.32 %), indicating a well-balanced amino acid composition. YX exhibited prominent total phenol and dietary-fiber contents, while YX and ZY had respective advantages in mineral-element accumulation. Among plant parts, leaves showed the highest contents of antioxidant compounds and free amino acids; roots had the highest dietary fiber content with superior retention after processing; stems contained the highest levels of macroelements and the lowest heavy metal contents. After low-salt pickling, β-carotene in stems and leaves increased significantly, with a maximum value of 3264.7 μg/100g detected in CWJ leaves. In contrast, soluble sugars, dietary fiber, and polyphenols decreased, mineral elements leached out, and heavy metals slightly increased. The flavor of pickled and dried mustard was dominated by sweet amino acids, with alanine and glutamic acid contributing to sweetness and umami, respectively. Overall, the nutritional quality and safety of both fresh and pickled and dried products varied among cultivars and plant parts. CWJ exhibited the best comprehensive quality, with leaves showing prominent contents of antioxidant components and taste-active amino acids, indicating clear potential for whole-plant graded utilization. These findings provide a theoretical reference for leaf mustard cultivar selection and value-added processing.