Studies On Extraction And Lipid-lowering Function Of Crude Polysaccharides In Abalone Viscus

Our country is rich in marine biological resources. As the yield of abalones is increasingevery year, lots of abalone viscus left after deep processing of abalones have been abandonedwithout a suitable treatment, which leads to enormous resource waste and environmentalpollution. The abalone viscera which occupies20-30%of body weight contains rich nutrients.Abalone viscus were used as raw materials to extract polysaccharides by PEF combined withenzymatic method. The optimum extracting condition was studied, and so were thephysiochemical indexes of crude polysaccharides in abalones viscus. Animal experiment wasdesigned to study lipid-lowering function of crude polysaccharides in abalone viscus. The mainresearch and results were as follows:(1)Effect of electric field intensity and pulse number on extraction of crude polysaccharidesin abalone viscus by PEF was studied. The experimental results showed that the extractioneffect was the best under the conditions that electric field intensity was30kV/cm, and pulsenumber was12.(2)Among acid proteinnase, neutral proteinnase and alkaline proteinnase, neutralproteinnase was the most suitable proteinnase to extract crude polysaccharides in abaloneviscus. Time was the most important factor affecting polysaccharides extraction with alkalineproteinnase, which was followed by ratio of material to liquid, temperature and amount ofenzyme. And all these factors had significant effect on extraction of crude polysaccharides inabalone viscus. The optimum extracting conditions were as follows: time was2.5h, the ratio ofmaterial to liquid was1:6, the amount of enzyme was2.4×10~4U/g, and temperature was55℃.(3)After treated by freeze-drying, the crude polysaccharide in abalone viscus was lightyellow powder which was adhesive, soluble in water but insoluble in organic solvent such asethanol and ethyl ether. This powder mainly contained60.4%polysaccharides,17.9%protein,6.0%fat and10.9%moisture. The polysaccharide extracted from abalone viscus in this paperwas a kind of mucopolysaccharide which few proteins were attached to. (4)The content of heavy metal cadmium was determined by atomic absorption method.After treated by freeze-drying, the average content of heavy metal cadmium in crudepolysaccharides of abalone viscus was0.4mg/kg.(5) Effect of crude polysaccharides in abalone viscus on lowering hyperlipidemia wasstudied through experiments in mice. The conclusion showed that crude polysaccharides inabalone viscus didn't have harmful effects on the growth of mice. All three doses of thepolysaccharides could effectively decrease concentrations of TG, TC and LDL-C in the serum,and increase the concentration of HDL-C in the serum, which indicated crude polysaccharidesin abalone viscus could obviously prevent the rising of TG, TC and LDL-C level as well as thedropping of HDL-C level. The AI values of three doses of the polysaccharides were alsoremarkably lower than that of high lipidic group, which indicated crude polysaccharides inabalone viscus could reduce the risk of atherosclerosis. It was concluded that crudepolysaccharides in abalone viscus could effectively inhibit the rising of blood lipid,consequently preventing hyperlipidemia.(6) Effect of crude polysaccharides in abalone viscus on fat quality oxidation in mice wasstudied by determination of serum MDA and SOD. The middle and high doses ofpolysaccharides could effectively decrease MDA level in serum, but the low dose could notmake MDA level in serum return to the normal level. There was significant difference observedbetween the three doses groups and high lipidic group in increasing SOD activation, though theeffect of high dose group wasn't as good as the others. The analysis showed in a certain rangeof dosage, crude polysaccharides in abalone viscus could obviously decrease MDA level andrise SOD activation to reduce free radicals in serum and the risk of atherosclerosis.(7) Pathological observations of liver showed that crude polysaccharides in abalone viscuscould reduce fat accumulations on livers of hyperlipidemic mice, and be helpful in preventionand treatment of atherosclerosis.