| Abalone is popular with people, which is one of "marine products one of eight treasure" with high nutritional value and medicinal value and economic value. The aim of this study is focused on improving water quality of aquaculture by planting Kandelia candel and investigating the influence of water quality, salinity and temperature on the growth of the abalone; the pigment of abalone shell was extracted and purified, then its stability was investigated; a new β-glucosidase from digestive gland of abalone was purified and characterized; extraction and purification of polysaccharide from abalone visceral was also researched. The results provided significant basis for factory farming and high value utilization of abalone.In the first part of this paper, the effect on water quality of aquaculture through planting Kandelia candel was studied, and the influence of water quality, salinity and temperature on the growth of the abalone were investigated. It was shown that the Kandelia candel could obviously improve the water quality and significantly influenced the growth of abalone (P<0.05); by setting the salinity of 29%o as control, different salinity had no significant influence on the growth of abalone (P>0.05); by setting temperature of 20℃ as control, different temperatures had no significant influence on the survival rate of abalone (P>0.05), whereas the mean daily body weight and shell length increment were significant different from those of control group (P<0.05), except those of 22℃.In the second part, the extraction and purification process of abalone shell blue-green pigment were established using solvent extraction method and macroporous resin. The separation process conditions of HZ820 macroporous resin were as follow:the concentration of the sample was A609 0.776 with the flow rate of 1.5mL/min at pH6; 70% ethanol was selected as elution solvent at pH 2 and the elution flow rate was 0.5mL/min, the color value was 120.81. The physicochemical properties of abalone shell blue-green pigment were investigated. The pigment was was stable at the temperature range of 0-100℃ and pH from 1 to 14, it could coexist with common metals; Sucrose, glucose and other common food additive had no adverse impact on pigment; both Na2SO3 and H2O2 have depigmentation effect on it; the pigment was stable in indoor dark place and indoor astigmatic place, but easily be influenced by UV light irradiation and faded in sun light.In the third part of this paper, a new P-glucosidase from digestive gland of abalone was purified and characterized. The β-glucosidase with Mw of 74.6 kDa was obtained after using ammonium sulfate precipetation, dialysis, DEAE-Sepharose fast flow chromatography and Sephacryl S-100 chromatography. The study of enzymatic charateristics of β-glucosidase was performed. The β-glucosidase exhibited optimal digestion activity on geniposide at pH 5.5 and 50℃. It was stable from pH 5.0 to 6.0 and under 50℃. The enzyme activity was apparently promoted by Mn2+, Cu2+ and Ba2+. However, the activity was strongly inhibited by Al3+, EDTA, Fe3+ and Co2+, and SDS could inactivate the enzyme completely.In the fourth part of this paper, the purification process of abalone viscera polysaccharide was established, which combined enzyme-assisted extraction method, hollow fiber ultrafiltration membrane with ethanol precipitation. By single factor experiment and response surface analysis, the optimum extractive conditions of polysaccharide were determined as follows:liquid-solid ratio of 30.82:1, neutral protease dosage 3.12%, pH 6.5, temperature of 50℃, extraction time 3 h. The separation conditions of ultrafiltration membrane were as follow:the hollow fiber ultrafiltration membrane of MWCO 6 kDa was used, differential pressure was 0.04 MPa, the solution concentration was 6 mg/mL, the room temperature was selected and the times of wash was 3, polysaccharide retention rate was 93.16%. At last, the times of ethanol precipitation were 2, which contained heteropolysaccharide with concentration of 71.9%. |
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