Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China; The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane, QLD 4072, Australia.
The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane, QLD 4072, Australia; Kenya Agricultural Research Institute, Nairobi, Kenya.
Carbohydr Polym. 2015 Sep 20;129:92-100. doi: 10.1016/j.carbpol.2015.04.035. Epub 2015 May 4.
The molecular structure and gelatinization properties of starches from domesticated African rice (Oryza glaberrima) and its wild progenitor (Oryza barthii) are determined and comparison made with Asian domesticated rice (Oryza sativa), the commonest commercial rice. This suggests possible enzymatic processes contributing to the unique traits of the African varieties. These have similar starch structures, including smaller amylose molecules, but larger amounts of amylose chains across the whole amylose chain-length distribution, and higher amylose contents, than O. sativa. They also show a higher proportion of two- and three-lamellae spanning amylopectin branch chains (degree of polymerization 34-100) than O. sativa, which contributes to their higher gelatinization temperatures. Fitting amylopectin chain-length distribution with a biosynthesis-based mathematical model suggests that the reason for this difference might be because O. glaberrima and O. barthii have more active SSIIIa and/or less active SBEIIb enzymes.
对驯化的非洲稻（Oryza glaberrima）及其野生祖先（Oryza barthii）与亚洲驯化稻（Oryza sativa，最常见的商业稻）的淀粉的分子结构和胶凝特性进行了测定，并进行了比较。这表明可能存在有助于非洲品种具有独特特性的酶促过程。这些淀粉具有相似的结构，包括较小的直链淀粉分子，但在整个直链淀粉链长分布中具有更多的直链淀粉链，并且含量高于 O. sativa。它们还显示出更高比例的双和三层片横跨支链淀粉分支链（聚合度为 34-100），高于 O. sativa，这有助于提高其胶凝温度。用基于生物合成的数学模型拟合支链淀粉链长分布表明，造成这种差异的原因可能是 O. glaberrima 和 O. barthii 具有更多活性的 SSIIIa 和/或较少活性的 SBEIIb 酶。
