低温预榨-亚临界正丁烷提取光皮梾木油的理化性质及表征Physicochemical properties and characterization of Cornus wilsoniana fruit oil prepared by low temperature pre-pressing-subcritical n-butane extraction

Abstract

为获得高品质的光皮梾木油以作为生物柴油原料，采用低温预榨-亚临界正丁烷提取光皮梾木油，测定油脂提取率及光皮梾木油理化性质和脂肪酸组成，并利用热重分析仪、流变仪、傅里叶红外光谱仪分别对光皮梾木油的热稳定性、流变特性和官能团进行表征。结果表明：采用低温预榨-亚临界正丁烷提取光皮梾木油的油脂提取率为98.54%；光皮梾木油的酸值（KOH）为1.50 mg/g，碘值（I）为100.24 g/100 g，皂化值（KOH）为189.71 mg/g，折光指数为1.472 9；光皮梾木油的脂肪酸组分主要为亚油酸（38.70%）、棕榈酸（34.80%）和油酸（22.10%），不饱和脂肪酸的相对含量为64.73%；流变学分析结果表明光皮梾木油为非牛顿流体；热分析表明光皮梾木油具有一定的热稳定性；红外光谱分析表明光皮梾木油中富含不饱和脂肪酸，是制备生物柴油的优良原料。综上，采用低温预榨-亚临界正丁烷提取光皮梾木油，油脂提取率高，所提取的光皮梾木油热稳定性好、酸值低，可为生物柴油的制备提供优质原料。In order to obtain high quality Cornus wilsoniana fruit oil as a biodiesel raw material, low-temperature pre-pressing-subcritical n-butane extraction method was used to extract Cornus wilsoniana fruit oil. The extraction rate, physicochemical properties and fatty acid composition of Cornus wilsoniana fruit oil were measured. In addition, the thermal stability, rheological properties, and functional groups of Cornus wilsoniana fruit oil were characterized using a thermogravimetric analyzer, rheometer, and Fourier infrared spectroscopy. The results showed that the extraction rate of Cornus wilsoniana fruit oil using low-temperature pre-pressing-subcritical n-butane extraction was 98.54%. The acid value, iodine value, saponification value, and refractive index of Cornus wilsoniana fruit oil were 1.50 mgKOH/g, 100.24 gI/100 g, 189.71 mgKOH/g and 1.472 9, respectively. The main fatty acid components of Cornus wilsoniana fruit oil were linoleic acid (38.70%), palmitic acid (34.80%) and oleic acid (22.10%), and the relative content of unsaturated fatty acid was 64.73%. Rheological analysis showed that the Cornus wilsoniana fruit oil was a non-Newtonian fluid. The thermal analysis showed that the Cornus wilsoniana fruit oil had a certain degree of thermal stability. Infrared spectrum analysis showed that the Cornus wilsoniana fruit oil was rich in unsaturated fatty acid, which was an excellent raw material for biodiesel production. In conclusion, the low-temperature pre-pressing-subcritical n-butane extraction for the Cornus wilsoniana fruit oil has high oil extraction rate, and the oil extracted has good thermal stability, low acid value, and can be used as excellent raw materials for the preparation of biodiesel.

Keywords

• 低温预榨；亚临界萃取；正丁烷；光皮梾木油；热稳定性；生物柴油
• low-temperature pre-pressing; subcritical extraction; n-butane; cornus wilsoniana fruit oil; thermal stability; biodiesel