马铃薯淀粉糊相对分子质量在超声场中的变化规律

为揭示超声场对淀粉相对分子质量的影响,以马铃薯淀粉糊为研究对象,采用凝胶渗透色谱仪测定了不同超声场条件与不同马铃薯淀粉糊质量浓度对马铃薯淀粉相对分子质量的影响。研究结果表明:马铃薯淀粉糊的数均相对分子质量、重均相对分子质量、峰均相对分子质量都有一定程度的降低,表明超声场中,淀粉分子发生降解,降解程度随作用时间的延长而增大,随超声强度的增大,淀粉分子进一步降解,但降解程度减小;淀粉糊的质量浓度越低受超声场的影响越大。超声作用时间对马铃薯淀粉糊相对分子质量分布宽度的影响规律是:初始阶段降解是一个随机过程,相对分子质量分布变宽;中间阶段转变为一个非随机过程,淀粉糊相对分子质量分布变窄;最后阶段相对分子质量分布趋于一个极限值。

Changes in Relative Molecular Mass of Potato Starch Paste in Ultrasonic Field

The purpose of this study was to evaluate the effect of ultrasonic field on the relative molecular mass of starch. We examined the changes in the relative molecular mass of potato starch as affected by different ultrasonic treatment conditions and different concentrations of starch paste by gel permeation chromatography. The results showed that the number-average relative molecular mass (Mn), weight-average relative molecular mass (MW) and peak-average relative molecular mass (Mp) of potato starch paste were decreased by ultrasonic treatment, indicating that the degradation of starch molecules was increased with irradiation time and decreased with ultrasonic intensity. The effect of ultrasonic field on the starch paste was increased with the decrease in starch paste concentration. The initial stage of the ultrasonic degradation of the starch paste was a random process and then the relative molecular mass distribution became wider. However, the middle stage was a non-random process and the relative molecular mass distribution became narrower. The relative molecular mass distribution tended to a limit valu e in the final stage.