Blueberry Leaves Superoxide Dismutase Extraction And Purification And Application

Vaccinium vitis-idaea Linn is a abundant resources in China which belong to Ericaceae family of blueberry genus. Presently, fruit of this species is used in the production of jam wine beverages. However the leaves of Vaccinium vitis-idaea Linn has never been used. The leaves of Vaccinium vitis-idaea Linn contains many kinds of compounds, such as arbutin, ursolic acid, tannin and superoxide dismutase (SOD), SOD is a specific metalloproteinase to clear the superoxide anion radica1(O2·-),which applied in medicine, food and daily life is the most abundant than other kinds of compounds in Blueberry’s leaves.In our study, we extracted superoxide dismutase from blueberry leaves, trying different methods to purify and modify it, and then we also carry out a primary research on its application.1. Taking the ultrasonic power, time, liquid material ratio as single factor to design the experiments, we identified the different influences of those three factors on the yield of superoxide dismutase extracted from blueberry leaves. We chose ultrasonic power, time and liquid-material ratio as the variables to design the response surface. Summarized the results of those different design, we concluded that the optimum parameters for the ultrasonic extraction superoxide dismutase from blueberry leaves are as follows:ultrasonic power780W, ultrasonic time5.8min, liquid material ratio2.4:1.2. We extracted the superoxide dismutase by ultrasonic fragmentation from the crude blueberry leaves, and then purified it through the selective thermal change, dialysis, Sephadex G-75column chromatography, freeze-drying, etc. The UV scanning showed the absorption peaks at280nm and258nm, SDS-PAGE electrophoresis showed there were two significant protein stripes at the position of32kD and42kD, and the atomic absorption showed the SOD from blueberry leaves contained Zn, Mn, and Fe. Sum up the results above, the SOD from blueberry leaves has three forms, Fe-SOD, Mn-SOD, and Cu/Zn-SOD.3. Since the natural enzyme has a short half-life period and a poor stability. And as konwn chemical-modification can prolong its half-life and improve its stability. So we modified the enzyme in agent bovine serum albumin (BSA)by using glutaraldehyde as a cross-linker. And then the thermal stability, acid and alkali resistance of SOD have been enhanced after the modification what are benefit to the preservation and application of superoxide dismutase extracted from the blueberry leaves.4. Furthermore we found that when this blueberry leaves superoxide dismutase(the adding amounts of enzyme activity:1000U/mL) was added to fresh milk, yogurt, wine, liquor and other food products, the result showed that the activity of superoxide dismutase enzyme was1000U/mL in fresh milk,980U/mL in yogurt,1230U/mL in dry red wine,600U/mL in the28°white spirite,530U/mL in the36°white spirit. Those results clearly showed that the activity and stability of superoxide dismutase can be maintained for a long period when it was added in different foods as an additive. So, adding the SOD in the food is a good way to improve and enhance the nutritional function of the food.