Optimization of subcritical extraction process for cinnamon (Cinnamomum Cassia Blume) using response surface methodology

Subcritical extraction was optimized to maximize the extraction yield of flavoring compounds from cinnamon. The extracts of cinnamon were obtained at three different levels of extraction temperature (110–130 °C), time (20–60 min), and pressure (20–40 bar). Response surface methodology was used in order to optimize the subcritical extraction process. The suitability of each independent variable in the second-order polynomial regression model was evaluated on the extraction yield and flavoring compound contents. For optimum extraction yield, the optimum temperature, time, and pressure were determined as 130 °C, 60 min, and 26.63 bar, respectively. The contents of the flavoring compound predicted at optimum conditions were as follows: 10.01 mg/g at 110 °C, 20 min, and 20 bar for coumarin; 4.95 mg/g at 110 °C, 20 min, and 32 bar for cinnamic acid; 55 mg/g at 110 °C, 34.62 min, and 37 bar for cinnamldehyde; and 4.92 mg/g at 110.9 °C, 20 min, and 20 bar for cinnamyl alcohol.