Individual and Combined Coatings of Chitosan and Carnauba Wax with Oregano Essential Oil to Avoid Water Loss and Microbial Decay of Fresh Cucumber

The objective of the present study is to evaluate the effect of individual and combined coatings of chitosan (0.008 g center dot mL(-1)) and carnauba wax (0.1 g center dot mL(-1)) with oregano essential oil (OEO, 0.08 g center dot mL(-1)) to reduce dehydration and microbial decay of fresh cucumbers stored at 10 degrees C. Chitosan-OEO-wax films showed the lowest water vapor transmission rate (0.141 g center dot m(-2)center dot h(-1)), compared to single chitosan films (0.257 g center dot m(-2)center dot h(-1)). While chitosan-OEO films completely inhibited the in vitro growth ofAlternaria alternataand reduced the growth ofSalmonellaTyphimurium,Escherichia coliO157:H7, mesophilic bacteria, and fungi isolated from decayed cucumbers. Besides, the infrared analysis of chitosan-OEO-wax films showed shifts in O-H and N-H absorption bands, indicating possible hydrogen bonding between the components. Wax and wax-OEO were the most effective coatings to prevent weight loss in cucumbers during 15 days of storage at 10 degrees C, while the most effective antimicrobial treatments were chitosan and chitosan-OEO. Therefore, these results showed that carnauba wax and carnauba wax-OEO coatings were the most effective in weight loss, whereas chitosan and chitosan-OEO were the most effective to reduce the microbial load of the treated fresh cucumber.