Ethephon Residues and Product Quality of Tomatoes by Accelerated Ripeners

Ethephon residues and product quality of tomatoes treated with different accelerate ripening methods or concentrations of ethephon were determined.Tomatoes were treated by artificial ripener in the field .Post-harvest tomatoes were dipped in different concentrations of ripeners and let stay for several days before determination.Ethephon residues were analyzed by headspace gas chromatography.Lycopene and vitamin C contents were determined by liquid chromatography.The results indicated that ethephon residues were high in post-harvest fruit treated by dip method.It reached 1.98 mg/kg at a dip concentration of 4 000 mg/L. Ethephon residues exceeded national maximum residue limit (MRL) of 2 mg/kg by whether field smear method (highest residue level of 2.29 mg/kg) or post-harvest dip method (highest residue level of 3.14 mg/kg) at concentration of 6 000 mg/L.Meanwhile,the contents of lycopene,vitamin C,sugar and soluble solid obviously decreased by 55.6%,13.6%,13.6% and 7.1％respectively in tomatoes at dip concentration of 2 000 mg/L.But the content of organic acid did not decreased obviously.It was concluded that ethephon residue may exceeded MRL in tomatoes, at high concentration treatment,and the fruit quality may be significantly affected by means of accelerate ripening treatment.