Preparation and antioxidative properties of chitosan-glutathione-Gracilaria polysaccharide extract nanoparticles

• Main Authors: Yu-Min Tsou, 鄒裕民
• Other Authors: Ke-Liang Chang Bruce
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/81916177778350344838

碩士 === 國立臺灣海洋大學 === 食品科學系 === 94 === Abstract The Gracilaria tenuistipita is a common macroalgae in Taiwan. This research investigated the preparation and characterization of antioxidant capacity of chitosan-glutathione-Gracilaria polysaccharide extract nanoparticles using chitosan and Gracilaria polysaccharides hydrolysates as ingredients. After the hydrolysis of Gracilaria polysaccharides by cellulase, the reducing sugar increased gradually with increasing hydrolysis time. After hydrolysis for 24 hours, 80.5 % of the DPPH radical scavenging effect and 73.5 % of ferrous ion chelating effect and 93.6 % of the superoxide anion radical scavenging effect can be reached by the hydrolysate. Based on the light scattering measurement and entrapment efficiency analysis, the nanoparticles made by emulsification-droplet coalescence method using 0.28 % chitosan and 0.28 % glutathione and 0.82 % Gracilaria ploysaccharides hydrolysates has the best combination of size and encapsulation properties. The average particle diameter was 306 nm from light scattering measurement and entrapment efficiency was 78.2 %. However, SEM pictures show that they are 84 nm. In the scavenging of DPPH radical, both the glutathione and Gracilaria polysaccharide hydrolysates have good antioxidant capacity. At a concentration of 1 %, the scavenging effect of DPPH radical can reach about 80 % by polysaccharide extract from Gracilaria; About 90 % of ferrous ion can be chelated by Gracilaria polysaccharide hydrolysates. For Gracilaria polysaccharide extract and hydrolysates, the radical scavenging effect of the superoxide anion was about 70 %. The antioxidant capacity of nanoparticles increases continuously with increasing dissolution time. After a dissolution time of 180 minutes, 43.8 % DPPH radical scavenging effect and 40.1 % ferrous ion chelating effect and 32.1 % superoxide anion radical scavenging effect can be reached. The dissolution of the nanoparticles in a dissolution testing system is performed. The glutathione and polyphenol have higher release rates in simulated gastric fluid. After dissolution for 120 minutes, the total amount of glutathione and polyphenol released is 60.18 and 0.80 μg / ml respectively. The cell viability after the addition of Gracilaria polysaccharide hydrolysates and nanoparticles is examined. They have little effect on the growth of normal cell (CCD-966sk) and the survival rate is higher than 70%. It seems that the Gracilaria polysaccilaride hydrolysates can suppress the growth of HT-29 and MCF-7 cells. Their cell survival rates drop to 67.06 % and 52.13 % after the addition of 1.667 g / ml hydrolysates. The thermal and storage stability of nanoparticles vary in different pH value. With longer heating and storage time, the antioxidant capacity of the nanoparticles reduces gradually. In high pH value environment, the scavenging of DPPH radical remains relatively unchanged at 40 %. But for the scavenging of superoxide anion radical, the scavenging effect is close to 50 % at low pH value.