Effects of soil pH on nutritional and functional components of Chinese cabbage (Brassica rapa ssp. campestris).

The contents of functional and nutritional components of 13 cultivars of Chinese cabbage (CC, Brassica rapa subspecies campestris) were analyzed to compare the effects of soil pH of the greenhouse (pH 6.2) and outdoor (pH 7.6). The CC cultivated on pH 6.2 (CC-6.2) soil contained significantly increased amounts (2-9 fold) of pectin, crude protein, vitamin C and vitamin E compared to the counterpart (CC-7.6). The contents of ash and the minerals (Ca, Fe, Na, and Mn) were also significantly increased in CC-6.2. However, CC-6.2 contained 40-50% lower contents of reducing sugars, cellulose and crude fat than CC-7.6. CC-7.6 contained more glucosinolates, gluconasturtiin (18.33 vs. 1.16 nmol.g(-1) wet weight) and gluconapin (145 vs. 2 nmol.g(-1) wet wt), than CC-6.2. In conclusion, CC-6.2 had an improved texture (high pectin and low cellulose) and nutritional value (high in protein, Ca, Fe, vitamin C, and E), whereas the CC-7.6 had better taste (high in reducing sugars) and anticancer functionality (high in glucosinolates).