Degradation of anti-nutrients in processing of Vietnamese pickled mustard greens (Brassica juncea)

Present research was performed to evaluate the possible existence of anti-nutrients like oxalate, phytic acid, tannin, saponin, anti-trypsin in the raw mustard greens material as well as their accumulation/depletion tendency in pretreatments (soaking, blanching and sun drying) and lactic fermentation (pickling). Raw mustard greens were soaked in fresh water for 30 min. They were pretreated by blanching at 100°C in 15s or sun-drying for 4 h. The pre-treated samples were soaked in sterilized brine at ambient temperature for 7 days to produce the pickle. The raw, washed, blanched, sun-dried and pickled mustard greens were analyzed oxalate, phytic acid, tannin, saponin content and anti-trypsin activity. Results showed that raw mustard greens contained high amount of anti-nutrients. Blanching and lactic fermentation caused a significant degradation of anti-nutrients. Meanwhile, soaking resulted no change of anti-nutrient contents. Sun drying induced a minor degradation these components. Degradation of anti-nutrients in the pickled mustard greens showed a beneficial advantage for human consumption.