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Research on Biological Modification and Protection Activity of R-Phycoerythin from Porphyra Yezoensi

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Tutor: HuQiuHui
School: Nanjing Agricultural College
Course: Of Food Science
Keywords: Porphyra yezoensis,R-phycoerythrin,hydrolysis,antioxidation,antitumor,microcapsu
CLC: TS201.21
Type: Master's thesis
Year:  2011
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Seaweed cultivation were extensively plated in China, which was output 40,000 tons of dry goods annually, our country is the second largest seaweed produce all over world¡¯s. However, the deep processing technology drop behind,existing products and primary products were in the market, mostly crude product had not yet entered the application of deep-level and high-tech processing. In this study, seaweed from jiangsu province were used as raw materials. obtained pharmaceutical grade R-phycoerythrin, and studied the structure characteristics. enzymatic modification can obviously enhance activity in R-phycoerythrin. micro-capsule technology can protect its activity releasing slowly. The main results of research on R-phycoerythrin structural Characteristics and its in vitro biological activity assay were as follows:1. Study on amino acid composition of the yezoensis. Porphyra yezoensis was treated by the ultrasonic cell-break. After ammonium sulfate precipitation for two times and ultrafiltration filter, R-phycoerythrin pre-purified was crystallized precipitation for a week. In the result, R-phycoerythrin reached pharmaceutical grade (A562nm/A280nm> 2) was got which purity came to 2.05. The result of determination of amino acids assay was shown that R-phycoerythrin contains all kinds of essential amino acids except tryptophane which accounted for 37% of total amino acid. And the content order of essential amino acids was leucine, valine, threonine, isoleucine, lysine, phenylalanine and methionine. Among the whole amino acids, the quantity of glutamate is the most.2. Papain modified R-phycoerythrin optimum was built. The optimized parameters for enzyme hydrolysis R-phycoerythrin were as follows:papain enzyme concentration 25000 u/g, pH7, temperature 50¡æ, time 4 h. comparison of scavenging hydroxyl radical activity and reducing power between R-phycoerythrin and its enzyme hydrolyze production,confirmed that enzyme hydrolysis R-phycoerythrin could strongly increase reducing power and antioxidant effects:reducing power was 0.573, increased 2.35 times; scavenging capacity of 51.03%, increased 3.22 times.3. Besides, studies on the inhibitory effects for R-phycoerythrin enzyme hydrolyze production on human sarcoma cells U2O and human hepatoma cell HepG-2. As shown that R-phycoerythrin enzyme hydrolyze production possesses marked tumor inhibiting effect and enhanced with the increasing concentration. The IC50 value of R-phycoerythrin enzyme hydrolyze production for human sarcoma cell U2O was 1271.46¦Ìg/mL, for human hepatoma cell HepG-2 was 512.05¦Ìg/mL.4. Carboxymethyl chitosan/Cacl2 were used for the microcapsule wall for R-phycoerythrin. The optimized parameters for embeding R-phycoerythrin were as follows: potassium calcium 7%, carboxymethyl chitosan concentration 5%, R-phycoerythrin concentration of 1.25mg/ml. and effcet on R-phycoerythrin concentration is significant. The reducing power of R-phycoerythrin before microencapsulation (A700) was 0.244, after carboxymethyl chitosan/Cacl2 embedding was 0.32, reducing power increased 31.48%, cavenging hydroxyl radical activity before microencapsulation was 55.78%, and 68.64% later,23.05% increased.5. carboxymethyl chitosan/Cacl2 microcapsules smooth surface was observed under scanning electron microscope,which was freezed-drying treatment. The internal porous structure of the aperture become smaller gradually from the inside out. close to the surface, become more dense, outer skin Thin, about 0.2¦Ìm. Release behavior of microcapsules showed that the carboxymethyl chitosan/Cacl2 can be effectively controlled.
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