Comparison of physicochemical properties and flavor content of yuja (Citrus junos) powders prepared by different homogenization and drying methods

Abstract

We prepared various types of yuja powders from yuja juice, fruit, and seed (to maintain the unique yuja flavor) by using different homogenization and drying methods and investigated their physicochemical properties. To this end, ultrasonic homogenization and high-pressure homogenization, were carried out to obtain the yuja mixtures. These mixtures were subjected to via spray-drying, freeze-drying, and microwave vacuum-drying to obtain spray-dried, freeze-dried, and microwave vacuum-dried yuja powders, respectively. The moisture content of the spray-dried yuja powder was lower than that of the other two types: however, this powder had the smallest particle size, with the average particle size ranging from 4.11 μm to 15.19 μm. The freeze-dried and microwave vacuum-dried yuja powders exhibited irregular amorphous structures, whereas the spray-dried yuja powder exhibited a spherical shape, as revealed by scanning electron microscopy analysis. Moreover, the maximum electron-donating ability indicated by the DPPH test was 80% for the microwave vacuum-dried yuja powder, and the maximum ABTS radical scavenging ability was 74% for the freeze-dried yuja powder. The D-limonene content of the yuja powders ranged from 4.67 μg/g to 4.82 μg/g, with the maximum amount present in the freeze-dried yuja powder treated by ultrasonic homogenization.