Study on the Soxhlet’s Extraction of Star Anise Oil and Preliminary Investigation of Its Antibacterial Activity

Abstract

In this study, Soxhlet extraction method using ethyl acetate as a solvent was used to extract the volatile oil from star anise fruits. The best technological extraction conditions were obtained by a series of single-factor experiments. The antibacterial activity of star anise oil obtained by Soxhlet extraction method was preliminary determined. The result showed that the most important factor affecting the extraction rate of oil from star anise fruits was extraction temperature, followed by powder granularity, solid–liquid ratio, and extraction time. The best extraction conditions were as follows: 1:22 (w/v), 40 min, 120 °C, and 60–80 mesh, respectively. Under these conditions, the yield of star anise oil reached 25.9827 %. It was proved that star anise oil extracted by Soxhlet extraction method could reduce the cost of investment equipments, improve production significantly, and keep the high-quality and natural flavor of the essential oil. Antibacterial experiment demonstrates that star anise oil method has a strong inhibitory effect against Escherichia coli and Bacillus subtilis, so that it could be applied as a natural and environment-friendly antibacterial agent in many areas, such as food products and pharmaceutical sectors.