Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA.
J Agric Food Chem. 2011 Jul 13;59(13):7385-92. doi: 10.1021/jf2007584. Epub 2011 Jun 3.
This study aimed to characterize and compare the chemical structures, physical properties, and enzymatic hydrolysis rates of five sorghum starches (6B73, 6C21, 6C69, 7R34, and X789) with that of corn starch (B73). Sorghum kernels consisted of 68.7-70.6% starch, more than the B73 corn (67.4%). Sorghum starches displayed higher gelatinization temperatures (66.6-67.4 °C), greater gelatinization enthalpy changes (13.0-14.0 J/g), and greater percentages of retrogradation (60.7-69.1%), but slower enzymatic hydrolysis rates (83.8-87.8% at 48 h) than the B73 corn starch (61.7 °C, 10.1 J/g, 51.5%, and 88.5%, respectively). These differences could result from the sorghum amylopectins consisting of fewer short branch chains (DP 6-12) (12.8-14.0%) than the corn amylopectin (15.0%). The sorghum starches showed greater peak and breakdown viscosities but lower setback viscosities than the B73 corn starch, resulting from the lower amylose content of the sorghum starches. After 96 h of fermentation, most ground sorghums exhibited lower ethanol yields (30.5-31.8%) than the ground B73 corn (31.8%).
本研究旨在对五种高粱淀粉（6B73、6C21、6C69、7R34 和 X789）的化学结构、物理性质和酶水解速率进行表征和比较，这些淀粉的性质与玉米淀粉（B73）的性质相对比。高粱籽粒中淀粉含量为 68.7-70.6%，高于 B73 玉米（67.4%）。高粱淀粉的糊化温度（66.6-67.4°C）较高，糊化焓变化较大（13.0-14.0 J/g），回生率较高（60.7-69.1%），但酶水解速率较慢（48 小时时为 83.8-87.8%），而 B73 玉米淀粉的相应值分别为 61.7°C、10.1 J/g、51.5%和 88.5%。这些差异可能是由于高粱直链淀粉中短支链（DP 6-12）的比例（12.8-14.0%）比玉米直链淀粉（15.0%）少。与 B73 玉米淀粉相比，高粱淀粉的峰值和崩解黏度较大，但回生黏度较小，这是由于高粱淀粉的直链淀粉含量较低。发酵 96 小时后，与粉碎的 B73 玉米相比，大多数粉碎的高粱的乙醇产量（30.5-31.8%）较低。
