Effect of Microwave Treatment on the Retention of Bioactive Compounds in Turmeric (Curcuma longa L.)

Parmar R and Dabhi MN

Published on: 2025-04-01

Abstract

Turmeric, an ancient spice, has long been valued as an important source of curcuminoids, which contribute to their powerful antioxidant and health-promoting properties. This study investigated the effect of microwave power (250-650 W) and slice thickness (2-6 mm) on the quality of dried turmeric in terms of antioxidant activity (DPPH), curcumin content, oleoresin, and volatile oil. Optimal conditions for microwave power and slice thickness can be achieved by optimizing the process through simulation and mathematical modelling using response surface methodology (RSM). The study found that slice thickness and microwave power had significant linear effects on antioxidant activity, curcumin, and oleoresin, with slice thickness generally showing a negative impact and microwave power showing both positive and negative impacts depending on the parameter. Interaction effects were mostly non-significant, except for oleoresin, where it was negatively significant. Quadratic effects were generally non-significant, except for microwave power on antioxidant activity and both slice thickness and microwave power on oleoresin. For volatile oil, only microwave power showed a significant impact, with a positive linear effect and a negative quadratic effect.