Bioactive Properties of Blanched and Unblanched Kumquat Slices Dried With Different Drying Methods

The objective of this study was to investigate the effect of blanching and different drying methods on the phytochemical properties of kumquat slices. The sliced fruits were dried using four different drying methods: hot air drying, vacuum drying, ultrasound-assisted osmotic pretreatment followed by hot air drying, and microwave-assisted hot air drying. The drying methods with pretreatment led to a significant loss of bioactive properties of kumquat slices compared to the drying methods without pretreatment. Generally, the best results in terms of the investigated functional properties were determined with the vacuum drying method. The highest total phenolic, ascorbic acid, IC50 and flavonoid components values were determined in the samples dried by the vacuum drying method without pre-treatment. Ultrasound-assisted osmotic pre-drying with the hot air drying method, with pretreatment significantly reduced the amount of total phenolic, carotenoid, ascorbic acid, HMF and flavonoid components of kumquat slices. According to the results of the research, the most suitable methods for producing dried kumquat with high bioactive component content and antioxidant properties were determined as vacuum drying, hot air drying, and microwave-assisted hot air drying without pre-treatment, respectively.