A novel infrared pulse-spouted freeze drying on the drying kinetics, energy consumption and quality of edible rose flowers

Rose flowers were dried by infrared freeze drying (IRFD) at different temperatures without and with pulsed spouted system, which is called novel infrared pulse-spouted freeze drying (IRPSFD). Drying kinetics, water activity, color, total phenolics content (TPC), and total anthocyanins contents (TANC) were investigated and compared with freeze drying (FD) as a control. The required time and energy for drying processes were also evaluated. Compared to FD, IRPSFD could shorten the processing time by 8–30% and save 15–36% of the total energy consumption. Pulse-spouted mode application and high drying temperature could shorten the total drying time and save energy. FD samples possessed the highest lightness (L*) value and lowest redness (a*) value. Compared with IRFD samples, the volatile profiles of IRPSFD samples were similar to those of FD samples. Moreover, the TPC of IRPSFD samples was slightly higher than that obtained by IRFD samples at each temperature. Therefore, the pulse-spouted mode application not only reduced the required processing time and total energy consumption but also improved the overall quality of the products.