Three-liquid-phase Salting-out Extraction And Component Analysis Of Lipids In The Abalone Viscera

With the production of abalone increasing, there are more and more abalone viscera produced during the processing. At present, abalone viscera are used as animal feed additives, and the resources are underutilized. Abalone viscera consist of rich lipids, proteins and polysaccharides, and the contents (dry weight) are21.1%,52.1%and23.1%respectively. Therefore high-value utilization of the abalone viscera is very important. Presently, there are barely reports about abalone viscera, these methods cannot separate different components at the same time, and the loss ratios of the components are usually high. In addition, the problem of heavy metal elements in the final products is not concerned. In this paper, a novel three-liquid-phase salting-out extraction (TLPSOE) system was developed. This study provided a simple method for the extraction and separation of lipids and other effective components from the abalone viscera, and this method could remove the heavy metal elements from the final products dramatically.Based on the research in our laboratory, a novel TLPSOE system was established by screening. The system had the high extraction efficiency and stability, also could remove the heavy metals elements dramatically. The optimal operation conditions of TLPSOE system were established as:18.6%salt (citric acid:sodium citrate=1:8, mass ratio)(w/w),18.6%ethanol (w/w),25.9%hexane (w/w),4.9%abalone viscera (w/w). Under these conditions, the recoveries of lipids, proteins and polysaccharides were57.8±1.3%,63.8±0.5%and65.5±0.7%respectively.The effect of removing the heavy metal elements was investigated, and the mechanism was discussed preliminarily. The results showed that the contents of As, Cd, Cr, Hg, Pb and Cu in abalone viscera lipid were10.54mg/kg,0.094mg/kg,2.56mg/kg,0mg/kg,0.88mg/kg and0.96mg/kg respectively, and all the rates of removing Cr, Hg, Pb and Cu were more than80%. Experiments showed a positive correlation with the concentration of salt and the distribution of heavy metal elements in each phase, which explained that the complexation of sodium citrate was the leading factor of removing heavy metal elements.A series of characteristics of the lipids extracted by TLPSOE system were determined, including physical and chemical indicators, fatty acid composition, pigment content and antioxidant activity. The results showed that the content of polyunsaturated fatty acids in abalone viscera lipids was29.57%, and the ratios of arachidonic acid (ARA) and eicosapntemacnioc acid (EPA) were12.33%and9.29%respectively. Abalone viscera lipids were rich in carotene and chlorophyll a, and the contents were0.92μg/mg and1.55μg/mg respectively. The antioxidant activity was determined by DPPH means and ABTS means. The IC50values were1.18mg/mL and2.87mg/mL, and it showed that the ability of removing fat-soluble free radicals was stronger.