Drying of Lemon Myrtle (Backhousia citriodora) Leaves: Retention of Volatiles and Color

Lemon myrtle plant (Backhousia citriodora) leaves were dried at three different drying temperature conditions (30, 40, and 50C) in a fluidized bed dryer. The retention of the principal volatile compound, citral, was analyzed in dried products obtained at these three drying conditions. The changes in the color parameters L*, a*, b* of leaves were also analyzed. More than 90% of citral was retained at 50C drying temperature, whereas the retention at 30 and 40C was 81 and 85%, respectively, suggesting that higher temperature is beneficial to achieve higher retention of volatiles. However, in terms of the color, all the color parameters were changed maximum at 50C drying temperature unfavorably, suggesting that the higher temperature drying causes more degradation of the pigment. Blanching of the leaves in hot water at 80C for 1min prior to drying did not result in any improvement in volatile retention or color.