Abstract:In this study, subcritical water extraction (SWE) was used to extract octacosanol from filter sludge, and the extraction process was optimized by single factor test and response surface analysis. The components of the extracted octacosanol sample were analyzed, and its extraction efficiency was examined through the comparison with the traditional hot ethanol reflux extraction method. The results showed that the optimal conditions for subcritical water extraction of filter sludge were as follows: amount of added filter sludge, 250 g; extraction time, 65 min; extraction temperature, 180 ℃; extraction pressure, 4.5 MPa. Under such conditions, the extraction rate and purity of octacosanol extracted by the subcritical water method were 29.77% and 70.89%, which were significantly higher than those obtained by the hot ethanol reflux extraction. The obtained samples were analyzed by GC-MS technology and infrared spectroscopy, and contained not only octacosanol, but also other higher fatty alcohols such as heneicosanol, hexadecanol, heptadecanol, triacosanol, campesterol, and heptaethylene glycol, which are beneficial to the human body due to their antioxidant activity and cholesterol-lowering effect. These results indicate that the octacosanol preparation method by subcritical water extraction has advantages such as high extraction rate, high purity, greenness and environmental friendliness, which provides a certain reference and theoretical basis for the high-value utilization of octacosanol in sugar factory’s filter sludge.
