The Effect of Ozone on Rhyzopertha dominica, Tribolium Castaneum, and Technological Properties of Wheat Flour

Abstract

As an alternative to synthetic pesticides, ozone has been used to combat insects in stored grain. This study aimed to examine the lethal effect of a minimum dose and time combination on insects, the potential effect on insect spiracles and cuticles, as well as technological properties of wheat flour. At various exposure durations, ozone concentrations of 0.428 g/m3 (200 ppm) were used for 2, 4, and 6 h. Ozone gas was administered to the eggs, larvae, and adults of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). For R.dominica, adults were significantly more resistant to ozone gas than the larval and egg stages. For T.castaneum, adults and larvae seem to have a similar ozone susceptibility, and both were more resistant than eggs. This resistance was largely dependent on the insect species and exposure duration. The scanning electron microscope (SEM) showed multi-action on the cuticle, spiracles, and antennae of the insects treated by ozone. Wheat flour exracted from grains exposed to 0.428 g/m3 ozone for 6 h was subjected to further physiochemical analysis. Germination of ozone-treated wheat grains was 77%, compared to 83% of the untreated ones. The chlorophyll content of treated and untreated grains was 1.65 and 1.07 mg/g, respectively. The protein, fat, fiber, ash, and total carbohydrate contents of the ozone-treated samples (wholemeal and flour) did not differ significantly compared to the control. The rheological properties of wheat flour showed that ozone significantly decreased its water absorption (WA) from 56.21 to 55.81% while increasing dough development time (DDT) and dough stability time (DST). All sensorial parameters did not differ significantly between ozone-treated and untreated samples. Pan bread made from the flour of ozone-treated grains was fresher than the control bread.