Zhou Cunshan, Ma Haile
College of Biological and Environmental Engineering, Jiangsu University, Zhen Jiang 212013, People's Republic of China.
J Agric Food Chem. 2006 Mar 22;54(6):2223-8. doi: 10.1021/jf052763h.
Polysaccharide from Porphyra yezoensis (PYPS) was degraded by ultrasound in this study. The changes of intrinsic viscosity with various conditions, such as ultrasonic power, irradiation time, reaction temperature, initial pH value of solution, and its concentration, were investigated by using Ubbleholde viscometry. It was found that the ultrasonic degradation rate of PYPS solution increases with the increase of ultrasonic power and reaction temperature and the decrease of the initial pH value of the solution. The order of the susceptibility of initial PYPS concentrations on degradation is 0.75 > 0.5 > 1.00 > 2.00 g/dL. The mechanism about the ultrasonic degradation of PYPS may be explained by more for mechanical and less for radical effects. Relationships between degradation rate and ultrasound time are exponential functions. The activation energy of ultrasonic degradation of PYPS solution is 52.13 kJ/mol, which was calculated by the logarithmic form of the Arrhenius equation, and is lower than one for the acid or enzyme catalyzing degradation of similar glycosidic bonds.
本研究采用超声法降解条斑紫菜多糖（PYPS）。利用乌氏黏度计研究了在超声功率、辐照时间、反应温度、溶液初始pH值及其浓度等不同条件下特性黏度的变化。结果表明，PYPS溶液的超声降解速率随超声功率和反应温度的升高以及溶液初始pH值的降低而增大。初始PYPS浓度对降解敏感性的顺序为0.75 > 0.5 > 1.00 > 2.00 g/dL。PYPS超声降解的机制可能更多地是机械作用，而自由基作用较少。降解速率与超声时间之间的关系为指数函数。通过阿伦尼乌斯方程的对数形式计算得出，PYPS溶液超声降解的活化能为52.13 kJ/mol，低于类似糖苷键酸催化或酶催化降解的活化能。
