蜡质玉米淀粉中直链淀粉和支链淀粉的含量测定对比研究

Comparative Study on the Determination of Amylose and Amylopectin Content in the Waxy Maize Starch

采用双波长分光光度法测定蜡质玉米淀粉中直链淀粉和支链淀粉含量。根据直链淀粉和支链淀粉与碘形成复合物的吸收光谱,确定直链淀粉的检测波长分别为616 nm和431 nm,支链淀粉的检测波长分别为536 nm和755 nm。结果表明:直链淀粉在4~50 mg/L,支链淀粉在80~200 mg/L范围内符合朗伯-比尔定律;直链淀粉和支链淀粉均具有较好的精密度和准确度;直链淀粉与碘形成的复合物在60min内较支链淀粉稳定。通过对两种淀粉的测定比较,在蜡质玉米淀粉中,由于支链淀粉的稳定性较差,建议采用双波长分光光度法直接测定直链淀粉含量。

Using the dual-wavelength spectrophotometry to determine the amylose and amylopectin content in the waxy maize starch. According to the absorption spectra of iodine-amylose and amylopectin,the detection wavelength of amylose was 616 nm and 431 nm respectively,and the detection wavelength of amylose was 536 nm and 755 nm respectively. The results showed that the Lambert Bill law was obeyed in 4 ~ 50 mg/L for amylose and in 80 ~ 200 mg/L for amylopectin; amylose and amylopectin have good precision and accuracy; amylose-iodine complex is more stable than amylopectin in 60 min. By comparing the two kinds of starch,using the dual-wavelength spectrophotometry to direct determination of amylose content is recommended in the waxy corn starch due to the poor stability of amylopectin.