An improved method to obtain essential oil, flavonols and proanthocyanidins from fresh Cinnamomum japonicum Sieb. leaves using solvent-free microwave-assisted distillation followed by homogenate extraction

An efficient solvent-free microwave-assisted distillation followed by homogenate extraction method (SFMD-HE) was established to separate the essential oil, non-volatile flavonols and proanthocyanidins from Cinnamomum japonicum Sieb. leaves. In the SFMD-HE technology applied in this work, no excessive water was introduced into the system, which can reduce the loss of flavonols and proanthocyanidins in the subsequent extraction process, avoid the generation of hydrosol and improve essential oil yield. Furthermore, no drying was required, which can reduce the energy consumption. The homogenate process can reduce the production of dust and environmental pollution, meanwhile, avoid the degradation and deterioration of some thermo-sensitive compounds. Through comparison, solvent-free microwave distillation was selected as the optimal method, and the 71% ethanol volume fraction was chosen for homogenate extraction. Based on the yields of essential oil, flavonols and proanthocyanidins, the process parameters (microwave irradiation power and time for essential oil distillation; homogenate time, liquid-solid ratio, and ethanol volume fraction for flavonol and proanthocyanidin extraction) were optimized. Due to the combined effects of these parameters, greater advantages were found for the proposed process compared with traditional methods. Therefore, the proposed technique is a good alternative for dis- tilling essential oil and extracting non-volatile components from edible plants. (C) 2018 Production and hosting by Elsevier B.V. on behalf of King Saud University.