Studies on the antioxidant activity and shelf-life of bananas with low molecular weight chitosan by β-D-glucosaminidase

• Main Authors: Shao-Fu Lian, 連紹甫
• Other Authors: Po-Jung Chien
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/47968062380583920801

碩士 === 中國文化大學 === 生物科技研究所 === 97 === β-D-glucosaminidase widespread in nature, such as bacteria and fungi in a variety of microorganisms, which are endo-enzymes with specificity, can be hydrolysis chitosan into chitooligosaccharide and aminoglucosamine. In this study from Trichoderma viride in the β-D-glucosaminidase hydrolysis of chitosan to explore the biochemical characteristics of β-D-glucosaminidase. The molecular weight of 44 kDa, the optimum temperature of 40 °C, the tem- perature stability of 30 °C~60 °C, the optimum pH value of 6, pH values of the stability of pH 4~8. The effects of metal ions by adding Mg2+, K+ with the promotion of enzyme activity, and by adding Ca2+、Ba2+、Mn2+would inhibit enzyme activity. Preparation low molecular weight chitosan by β-D-glucosaminidase to determination of antioxidant capacity. Scavenging of DPPH radical of enzyme hydrolysis chitosan is highter non enzyme hydrolysis than 10 %, Metal ion chelating is highter than 70 %, Superoxide anion radical scavenging is highter than 22 %, Trolox equivalent antioxidant capacity(TEAC) is highter than 1.14 mM, Oxygen radical absorbance capacity(ORAC) can case of fluorescence suppression recession is highter than 13.3 %. At the same time, using low molecular weight chitosan to processe shelf-life of bananas, RT-PCR technology to analysis shelf-life genes of bananas, result show L-aminocyclopropane-1-carboxylic acid synthase (ACC synthase) and L-aminocyclopropane-1-carboxylic acid oxidase (ACC oxidase) have reduced the amount of performance to prove that low molecular weight chitosan indeed to extend the shelf-life of effect, and chitosan with the role of antibacterial. For the future to improve the international competitiveness of export fruit is a great help.