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

Abstract

Lemon myrtle plant (Backhousia citriodora) leaves were dried at three different drying temperature conditions (30, 40, and 50°C) 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 50°C drying temperature, whereas the retention at 30 and 40°C 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 50°C drying temperature unfavorably, suggesting that the higher temperature drying causes more degradation of the pigment. Blanching of the leaves in hot water at 80°C for 1 min prior to drying did not result in any improvement in volatile retention or color.

Keywords:

• Australian
• Citral
• Drying
• Herbs
• Lemon myrtle
• Water activity

ACKNOWLEDGMENTS

The authors thank Sibylla Hess-Buschmann, Australian Rainforest Products Pty Ltd for supplying the lemon myrtle leaves.

Notes

^a Mean of three replications.

The values tagged with same superscript letters in the column were not significantly different at the 5% significance level.