Role of ultrasound-assisted KCl catalysis in characteristic flavor and quality of liquid smoke from cypress wood.

This study aimed to improve the flavor and quality of liquid smoke by synergistically combining ultrasound and a catalyst (KCl) during the pyrolysis of cypress wood powder. The effects of KCl concentration, ultrasonic power, treatment duration, and temperature on the composition and physicochemical properties of the resulting liquid smoke were systematically investigated. The results showed that ultrasound significantly enhanced the catalytic efficiency, leading to a marked increase in phenolic compounds: guaiacol reached 0.76 mg/mL with total phenolics up to 16.95 mg/mL. Moreover, both the carbonyl content and the undesirable furfural were reduced. Besides, Higher ultrasonic power and longer duration could increase the lightness (L), pH, and transmittance, while decreasing redness (a) and yellowness (b*). In conclusion, the ultrasound-catalyst synergy effectively optimized both the sensory and physicochemical quality of liquid smoke.