in vitro Nitrite Scavenging Capacity of Litchi Pericarp Pigment

The nitrite scavenging capacity of litchi pericarp pigment was evaluated in vitro by spectrophotometric method and compared with those of tea extract and vitamin C. Results indicated that the reaction between litchi pericarp pigment and nitrite for 10 min resulted in perfect scavenging of nitrite. The scavenging rate against nitrite first increased and then tended to keep stable with increasing dose of litchi pericarp pigment. Heating treatment and low pH of reaction system could improve the scavenging effect against nitrite. As a result of heating treatment at 100 ℃ for 10 min, the nitrite scavenging rates of vitamin C at the concentration levels of 1 and 10 mg/mL were both the highest. Moreover, the nitrite scavenging rate of litchi pericarp pigment at the low concentration level of 1 mg/mL was (42.76 ± 0.98)%, which was higher than that of tea extract ((37.92 ± 0.79)%) (P0.05) at the identical concentration level; while the nitrite scavenging rate of tea extract was higher than that of litchi pericarp pigment at the high concentration level of 10 mg/mL (P0.05). Furthermore, high nitrite scavenging rate of litchi pericarp pigment was also observed under simulated gastric and body temperature conditions in vitro, with the values of (23.55± 0.45)% and (51.62 ± 0.91)% at the concentration levels of 1 and 10 mg/mL, respectively.