Abstract:

To reduce PAHs in vegetables, Vigna unguiculata was used as a material, and different concentrations of detergent, salt, rice wine, rice vinegar, vegetable oil and water were used to dip the pods of V. unguiculata. The PAHs of V. unguiculata were detected by HPLC-MS to screen the optimum purification method of PAHs in V. unguiculata. The removal effect of rice wine and rice vinegar on the PAHs of V. unguiculata was basically the same. In the rice wine and the rice vinegar treatment group, ∑PAHs decreased by 68.92% and 73.88%, respectively. ∑PAHs was the total concentration of 16 polycyclic aromatic hydrocarbons monitored with priority by the United States Environmental Protection Agency. Rice wine and rice vinegar had a remarkable removal effect on naphthalene, diphenyl(a,h) anthracene and hydrazine(1,2,3-c,d) pyrene, etc. Water washing could effectively reduce the content of hydrazine (1,2,3-c,d) pyrene in V. unguiculata, but increase the content of phenanthrene. Salt treatment could increase the ∑PAHs by 77.15%, by increasing the 2 and 3 ring of PAHs accumulation in V. unguiculata. Although the vegetable oil treatment could reduce the content of individual PAHs, but it introduced other PAHs and increased the ∑PAHs. The results of toxicity equivalent calculation showed that rice wine could effectively reduce the PAHs toxicity in V. unguiculata, so could the salt treatment. The rice wine and rice vinegar could effectively reduce the ∑PAHs and dibenzo (a,h) anthracene, as well as their toxic equivalent in V. unguiculata.

Key words: Vigna unguiculata, PAHs, soak and wash, toxic equivalent, purification effect