The Influence of Gaseous Ozone Fumigation on the Chemical and Mechanical Properties of Highbush Blueberry (Vaccinium corymbosum L.) Fruits

Ozonation is an effective method of post-harvest preservation and reducing the loss of health-promoting compounds such as phenolic compounds during storage. Fruits of highbush blueberry (Vaccinium corymbosum L.) have strong antioxidant properties, they are recognised as one of the most valuable sources of health-promoting bioactive compounds. In the present study, changes in total acidity and pH of highbush blueberry fruit depended on ozonation and storage time and genotype. The total acidity of fresh blueberries of tested genotypes ranged from 0.59 - 0,90 g·100 g⁻¹. The highest total acidity was recorded for clone ‘21’, which was ozonated for 15 min. It was found that the application of ozone gas during storage of V. corymbosum fruit had mainly positive effect on the content of analysed bioactive compounds. Results of our study showed that ascorbic acid content varied depending on genotype, storage time and ozonation. The average content of this antioxidant in the non-ozonated fresh fruit was 22.32 mg.100 g⁻¹, and slightly decreased with ozonated 15 min and 30 min - 21.87 mg.100 g⁻¹ and 21.95 mg.100 g⁻¹, respectively. Average content of total phenolic in fruits subjected to ozonation for 30 min. and stored for 15 days was higher by 10.3% in a comparison to control sample (fresh fruits). The antioxidant values of DPPH and FRAP in fruits subjected to storage and ozonation for 30 min. increased by 22.6% and 15.5%, respectively. Using ozone had a minor positive effect on the measured mechanical properties of the fruits. Throughout the different storage periods of blueberry fruits, there was a decrease in destructive energy and an increase in force.