双波长法测定南瓜中直链与支链淀粉含量

为建立同时测定南瓜中直链和支链淀粉的双波长比色法。本文采用正丁醇结晶法分离纯化南瓜中直链和支链淀粉并测定其含量。结果表明,分离纯化得到的直链和支链淀粉蓝值分别为0.874和0.196;根据双波长原理和扫描谱图,确定其测定波长为645、565 nm,参比波长为495、730 nm处测定南瓜中直链与支链淀粉含量;南瓜样品中直链淀粉占21.64%,支链淀粉占50.19%,总淀粉含量为71.83%,相对标准偏差分别为0.97%和1.06%,平均回收率分别为98.62%和99.42%,检出限分别为0.0116和0.0644 mg/mL。正丁醇结晶法能有效地分离南瓜直链与支链淀粉,双波长法可同时获得南瓜中3个淀粉含量指标,该方法既节省了样品,又提高了效率。同时,该方法的建立也为南瓜淀粉理化特性的研究提供了技术支持。

Determination of amylose and amylopectin in pumpkin with dual-wavelength colorimetric method

Dual-wavelength spectrophotometry was applied to the determination of amylose and amylopectin from pumpkin. N-butanol crystallization separation and purification of pumpkin in the linear and amylopectin,and content of them were mensurated. The results showed that the blue values of linear and amylopectin isolated and purified were 0.874 and 0.196,respectively. According to the principle of dual-wavelength spectrophotometry and scanning spectra,the contents of amylose and amylopectin in pumpkin were determined at the selected wavelengths of 645 and 565 nm with respective reference wavelengths of 495 and 730 nm. The amylose in pumpkin samples accounted for 21.64%,the amylopectin was 50.19% and the total starch was 71.83%. The RSD was 0.97% and 1.06%,respectively. The average recovery of amylose and amylopectin were 98.62% and 99.42%,respectively,while detection limit were 0.0116 and 0.0644 mg/mL. N-butanol crystallization method could separate and purify of amylose and amylopectin in pumpkin effectively. The detection method could obtain three kinds of starch content simultaneously. The developed dual-wavelength colorimetric method was not only cost-saving and efficient for determination of amylose and amylopectin,but also provide a basis for research on physicochemical properties of starch in pumpkin.