Nutritional Evaluation and Comparison of New Pak Choi Cultivars from China with Chinese Cabbage Cultivars Popular in Korea

The nutritional components of 14 new cultivars of pak choi (Brassica rapa L. ssp. chinensis) from China were analyzed and compared with 4 cultivars of Chinese cabbage (Brassica rapa L. ssp. pekinensis) popular in Korea. Leaves were separated into green parts (GP) and white parts (WP) for the analyses. The moisture and ash content in the 14 new cultivars of pak choi were not significantly different from the currently popular cultivars of Chinese cabbage. In addition, the levels of vitamin C and E were very similar between the two kinds of Brassica rapa. In contrast, the overall mineral content was higher in the new pak choi cultivars. Specifically, minerals important for human health, calcium and magnesium, were significantly greater in pak choi cultivars (calcium GP 2.57, WP 2.04; magnesium GP 0.422, WP 0.301 mg/g fresh weight) compared to currently popular cultivars (calcium GP 0.805, WP 0.477; magnesium GP 0.244, WP 0.101 mg/g fresh weight). Although the content of reducing sugars was similar, cellulose content (which correlates with the hardness of plant tissue) was four times higher in the new pak choi cultivars compared to currently popular cultivars. These results demonstrate that the new pak choi cultivars have superb nutritional benefits for human health and could be a good food source as a daily staple vegetable.