Quality and antioxidant activity of highbush blueberry fruit coated with starch-based and gelatine-based film enriched with cinnamon oil

In this study, the effect of starch-based and gelatine-based edible coating containing cinnamon oil on selected quality parameters and the metabolism of antioxidants in highbush blueberry fruit, in terms of extending their shelf life were investigated. Research showed that the application of cinnamon oil to edible coating positively influenced the quality of the fruit during storage. Coating with essential oil effectively inhibited the growth of yeast and mould in the fruit during storage. On the last day, the growth of yeast and mould in the fruit coated with cinnamon oil (10% COE) was 1.29 log cycles lower than in the control. Moreover, the essential oil reduced the loss of soluble solids but it did not significantly affect the acidity and weight loss of the fruit. Equally interesting was the effect of the coating with cinnamon oil on the antioxidant activity of the fruit. Blueberries coated with cinnamon oil were characterised by a lower ability to produce ROS, as well as a lower activity of antioxidant enzymes. On the final day, the level of ROS and the activity of SOD and CAT were lower than the control by 82%, 56% and 63% respectively. The level of polyphenols in the fruit coated with cinnamon oil was higher than in the control up to the 5th day of storage. However, the level of anthocyanins in this sample gradually decreased as the storage period extended. After 10 days, the loss of anthocyanins in the fruit with essential oil was around 37%.