EFFECTS OF FUMIGATION WITH ETHYL FORMATE ON THE QUALITY OF DATE FRUIT

Abstract

The date industry is still searching for a suitable alternative to methyl bromide and phosphine for insect disinfestations of date fruits. In a previous study, ethyl formate (EF) had been tested for fumigation of date fruit where an optimum concentration was determined resulting in 91.6% mortality rate of most resistant stage of carob moth (fifth-instars larvae). All physiological stages (eggs, pupae) were also controlled. In the present work, the effects of EF fumigation on fruit quality were studied. Date color was analyzed and EF residue was examined for acetate aldehyde, ethanol, ethyl acetate and ethyl formate. After treatment, the date quality for different parameters (score decay, sugar contents, pH value and acidity as well as volatile contents) was examined after 7 and 14 days of storage at 0, 5 and 20°C. No significant difference (P<0.05) between treated and untreated dates was observed regarding the date colour, pH value, acidity and sugar content. Residue levels were almost the same as in control sample for ethanol and EF after 7 and 14 days of storage, whereas the EF residue disappeared after 7 days of storage.