Influence of continuous exposure to gaseous ozone on the quality of red bell peppers, cucumbers and zucchini

The effect of continuous exposure to ozone on quality changes during the storage of red bell peppers, cucumbers and zucchini was investigated. Peppers were stored at 14 °C and were exposed to ozone at 0.1 and 0.3 μmol mol−1, while cucumbers and zucchini were stored at 12 and 8 °C, respectively, and exposed to ozone at 0.1 μmol mol−1. The content of fructose (2.75 g/100 g FW) and glucose (2.00 g/100 g FW) in red bell peppers exposed to ozone at 0.1 μmol mol−1 was increased by 8 and 7%, respectively, when compared to controls. Continuous exposure to ozone at 0.3 μmol mol−1, on the other hand, had no effect on fructose (2.52 g/100 g FW) and glucose (1.88 g/100 g FW) content. The content of vitamin C was significantly enhanced in red bell peppers exposed to ozone at 0.1 and 0.3 μmol mol−1 after 7 d of storage, however, this effect was not maintained. After 14 d, vitamin C content in peppers exposed to ozone at 0.1 μmol mol−1 was not significantly different from the control, whereas it was reduced at 0.3 μmol mol−1. Total phenolics content was increased in peppers exposed to ozone at 0.1 μmol mol−1, but was unaffected at 0.3 μmol mol−1. Continuous exposure of red bell peppers to ozone at 0.1 and 0.3 μmol mol−1 had no significant effect on weight loss, texture and colour. In cucumbers and zucchini, continuous exposure to ozone at 0.1 μmol mol−1 reduced weight loss by more than 40% and improved texture maintenance, while having no significant effect on their biochemistry. The findings from this study suggest that continuous exposure to ozone at 0.1 μmol mol−1 is a promising method for shelf-life extension of cucumbers and zucchini. Even though in red bell peppers continuously exposed to ozone at 0.1 μmol mol−1 sugars and phenolics content was increased, further work is still needed to better understand the exact mechanism of ozone action and its potential for the industrial use.