The present invention provides an antioxidant, whitening and antibacterial essential oil of Alpinia oxyphylla Miq kernel and its preparation method. The preparation method comprises the following steps: (i) breaking the Alpinia oxyphylla Miq kernels into a plurality of particles and (ii) subjecting the particles of Alpinia oxyphylla Miq kernel to a supercritical carbon dioxide extraction process while keeping the processing pressure at 350 bar-450 bar so as to obtain essential oil of Alpinia oxyphylla Miq kernel. The preparation method of this invention can not only avoid the loss of highly polar or volatile functional compounds during the extraction and the solvent residue problem, but also increase the proportion of functional compounds content in the extract, thereby obtaining a better antioxidant, whitening and antibacterial essential oil of Alpinia oxyphylla Miq kernel, rendering an extremely practical value.一種具抗氧化、美白及抗菌功能之益智仁精油及其製法,該製法包含下列步驟:(i)將益智仁碎化為多個益智仁顆粒;及(ii)使該等益智仁顆粒經一超臨界二氧化碳萃取處理,並使該超臨界二氧化碳萃取處理的壓力介於350bar到450bar之間,以獲得一益智仁精油。本發明之製法不但能避免萃取時益智仁之高極性或易揮發的功能性化合物的流失、無溶劑殘留的問題,且能提高萃取物中功能性化合物成分的含量比例,而能獲得具有更佳抗氧化、美白及抗菌功能的益智仁精油,極具實用價值。101‧‧‧步驟102‧‧‧步驟
