Abstract: The effects of lyophilized powder and water-soluble extract from spicy vegetables including green Chinese onion,
ginger, garlic and onion on the formation of N-nitrosodimethylamine (NDMA) were addressed under simulated conditions
in vitro and in nitrite reaction system. The results indicated that different types and amounts of spicy vegetables as well
as different reaction temperatures and times could promote or inhibit on the formation of NDMA. Green Chinese onion
powder, onion powder and ginger powder could significantly promote the formation of NDMA at simulated temperatures
of (4 ± 1) ℃ (for pickling), (25 ± 1) ℃ (room temperature), and (80 ± 1) ℃ (for processing) (P < 0.05), and they were the
most effective at 80 ℃. At the same temperature, the promotion of green onion powder and onion powder on the formation
of NDMA became significantly stronger with reaction time (P < 0.05), while ginger powder had no significant effect on the
formation of NDMA (P > 0.05). At the same temperature and reaction time, the promotion effect of spicy vegetables on the
formation of NDMA was significantly enhanced in a dose-dependent manner (P < 0.05). However, garlic powder and ginger
water-soluble extract exhibited an inhibition effect on the formation of NDMA at 4 or 25 ℃, and the latter (10%) was weaker
than the former. Garlic powder appeared to promote the formation of NDMA at 80 ℃. In conclusion, all four kinds of spicy
vegetables had no significant inhibitory effect on the formation of NDMA under simulated conditions.

Key words: spicy vegetable, simulated conditions, N-nitrosodimethylamine (NDMA)