Microwave-Assisted Extraction of Trigona Propolis: The Effects of Processing Parameters

Microwave-assisted extraction of Trigona propolis in closed vessel was applied to reduce the extraction duration and volume of solvent. The effects of operating parameters (temperature, duration, power applied and sample to solvent ratio) on the extract yield, total phenolic, total flavonoids and antioxidant activity measured by DPPH method were measured after extraction. Without temperature control, propolis extract showed improvement in yield and quality by extending the extraction duration at low microwave power. However, the yield dropped significantly and the ethanolic solvent was released when the vessel pressure increased dramatically at higher power applied. The effects of extraction duration, temperature and the sample to solvent ratio were further investigated using a constant power of 300 W with temperature control. As long as the temperature was precisely controlled below 125 degrees C, propolis extraction can be accomplished in shorter time (15 min) and less solvent (sample to solvent ratio of 1:5 (w/v)) without degradation compared to maceration.