Investigation of (+)-catechin stability under ultrasonic treatment and its degradation kinetic modeling

摘要

(+)-Catechin (CA) is extremely difficult to be extracted using ultrasound-assisted extraction technique as CA is unstable under high temperature and oxidation condition. Thus, the stability of CA under various ultrasonic treatment conditions was properly investigated in the present study. The degradation ratio of CA gradually increased with the increase in either the ultrasonic frequency or the input power when the ultrasonic frequency was below 135kHz or the ultrasonic power was below 0.45W/cm(2). Additionally, the primary degradation product of CA was identified as epicatechin (EC) that was epimerized by CA. Reaction kinetics analysis confirmed that the degradation of CA under ultrasonic treatment followed first-order kinetics. In addition, ultrasonic treatment induced the increase in kinetic constant (k) and frequency factor (A), while the apparent activation energies (E-a) of CA degradation only decreased at 135kHz. A mathematical model was established to accurately predict the degradation level of CA under various ultrasonic conditions. The results are of great significance for the ultrasonic extraction of CA from plants without sacrificing the recovery rate.Practical applications(+)-Catechin (CA), which is sensitive to many environmental factors, possesses many physicochemical properties and biological activities. However, due to limited investigations about using ultrasound to extract CA, the stability of CA under ultrasonic treatment was not well studied and no appropriate ultrasound-assisted extraction method for CA has been developed. Hence, it is essential to understand the stability of CA under ultrasonic treatment. In the present work, the stability of CA under various ultrasonic treatment conditions was properly investigated. A mathematical model was established to accurately predict the degradation level of CA under various ultrasonic conditions. The results are of great significance for the ultrasonic extraction of CA from plants without sacrificing the recovery rate.