Effect of silver nano-particles, ethanol, wax or methylcellulose-wax on shelf life and qualitative properties of Thomason navel oranges

In this study, effect of individual substance [ethanol 70%, colloidal silver Nano-particles (Nps) (0.5 ppm), benomyl 15%, wax or methylcellulose-wax] or their combinations at 8 °C was evaluated on prevalence of decay, textural and organo-leptic properties of Thomson novel oranges. Quality and sensory attributes were evaluated every two weeks for 16 weeks. After rinsing, fruits were treated by ethanol 70%, silver Nano-particles (0.5 ppm), or Benomyl 15%. Fruits were coated by commercial wax or methylcellulose- wax [MC-lipid (9:10, w/w)] using immersion method, and then were dried at ambient temperature. Uncoated fruits were used as the control ones. This research was performed using a factorial experimental model in a completely randomized design with 5 replications at an accuracy rate of 95%. During storage, the minimum and maximum of decay were observed for the fruits treated by nanosilver and ethanol, respectively. The percent of decay for the control fruits was smaller than that of the fruits treated by ethanol. No significant changes were observed between the fruits coated by wax and methylcellulose (P>0.05). Texture analysis showed that the fruits coated by wax or methylcellulose-wax had much better firmness in comparison with the control or disinfected fruits (P<0.05). The panelists reported that the highest and lowest organoleptic properties for methylcellulose and wax, respectively. No significant difference was observed between the two types of coatings in their appearances.