Sensitivity analysis and response surface optimization for process- product characteristics of refractance window dried Curcuma longa

Abstract

Abstract This work addresses the sensitivity and optimality of process product characteristics of refractance window dried Curcuma longa. Based on response surface methodology, parameters such as water bath temperature (65–95°C), drying time (75–360 min) and air-velocity (0.5–1 m/s) have been optimized to achieve best combinations of total phenolic content, total flavonoids content, curcumin content, antioxidant activity, moisture content, and colour indices. The best fit model, influence of independent variables on dependent variables and analysis of variance were considered. The optimized conditions for temperature, drying time, and air velocity were found as 95°C, 75 min, and 0.76 m/s respectively. The results indicated novel optimized conditions for refractance window drying of Curcuma longa in terms of antioxidant activity, total phenolic content, total flavonoid content, curcumin concentration, moisture content, and colour indices. The findings affirmed greater sensitivity of water bath temperature and drying time but not air-velocity.