Physic-Chemical Properties And Chemical Components Of Semen Allii Fistulosi Oil Extracted By Supercritical Carbon Dioxide

Semen Allii Fistulosi is the dry and mature seed of Allium fistulosum L., which is a centuried traditional Chinese medicine initially recorded in "ShenNong’s Herbal". Research shows that Semen Allii Fistulosi contains arachidic acid, hexadecanoic acid, octadecanoic acid, oleic acid, and linoleic acid. However, there is no comprehensive report on qualitative and quantitative analysis of chemical compositions, as well as extraction process and physicochemical properties of Semen Allii Fistulosi oil.In comprehensive consideration of problems on extracting efficiency, product purity and solvent residual, the study applied supercritical carbon dioxide to extract Semen Allii Fistulosi oil. According to the yield of product, the research used response surface methodology to optimize the extraction process and determined the optimal parameters. At the same time, physicochemical properties, fatty acid compositions and three kinds of trace elements were measured, so as to supply theoretical foundation on comprehensive utilization of Semen Allii Fistulosi.Results of the study indicate as follows:1. The results showed that extraction pressure, temperature, and time have significant influences on the yield of Semen Allii Fistulosi oil. The optimal process parameters of supercritical carbon dioxide extraction were obtained as follows:range of comminution granularity is from300μm to450μm, loading100g, extraction pressure27.5MPa, extraction temperature39.7℃, extraction time94.6min, CO2flow rate20L/h, the first separation pressure7-8MPa and temperature40℃, the second separation pressure4-6MPa and temperature35℃. Under these conditions, the extraction rate was up to14.80%.2. Identified by gas chromatography-mass spectrometry, fatty acids in the oil were composed of34.47%saturated fatty acids and65.53%unsaturated fatty acids. Saturated fatty acids mainly included octadecanoic acid, hexadecanoic acid, and arachidic acid. Unsaturated fatty acids were rich in oleic acid and linoleic acid. Furthermore, a-Linolenic acid and a-tocopherol were separated from the oil. Besides, seventeen components were separated from the oil for the first time, such as myristic acid, palmitoleic acid, margaric acid, Behenic acid, and so on.3. The results showed that the contents of Fe, Zn and Mn were9.45mg/kg、0.98mg/kg and1.21mg/kg respectively. Experimental results were the same as bulb of Allium fistulosum L. reported in the literature.4. Semen Allii Fistulosi oil was transparent and light color. The results showed that the Semen Allii Fistulosi oil extracted by supercritical carbon dioxide was high purity and good quality.