摘要
选用4种不同的淀粉,通过考察回生特性,探究相对分子质量、链长分布、短程有序性、相对结晶度及半结晶层状结构等精细结构影响回生特性的机理.结果表明:与糯米淀粉和粳米淀粉相比,小米淀粉和黑米淀粉回生值、硬度和热焓值较大,糯米淀粉储藏前后硬度和回生后的热焓值均较小,具有较好的抗回生特性.研究发现,这是由于小米淀粉和黑米淀粉的直链质量分数较高(小米淀粉15.55％、黑米淀粉11.22％),支链淀粉峰MW较大(小米淀粉MW=2.12× 107 g/mol、黑米淀粉MW=2.25 × 107 g/mol)、半结晶层厚(小米淀粉d=6.978 4 nm、黑米淀粉d=6.698 6 nm),且中长链占比大(小米淀粉B1链占比40.91％),易形成稳定的双螺旋结构,具有更高的表面有序度(小米淀粉0.76、黑米淀粉0.70),回生后2种淀粉分子重排更有序稳定.
Abstract
In this paper,four different kinds of starch were selected to explore the mechanism of fine structure af-fecting the regenerative properties,such as relative molecular weight,chain length distribution,short-range order,relative crystallinity and semi-crystalline layered structure,etc.The results indicated that,compared with glutinous rice starch and japonica rice starch,millet starch and black rice starch had higher recovery values,hardness and en-thalpy values,while glutinous rice starch had lower hardness and enthalpy values before and after storage,showing better resistance to recovery.The study found that the reason was the high amylose content of millet starch and black rice starch(millet starch 15.55％,black rice starch 11.22％).The amylopectin peak MW was large(millet starch MW=2.12 × 107 g/mol,black rice starch MW=2.25 × 107 g/mol),the semi-crystalline layer was thick(millet starch d=6.978 4 nm,black rice starch d=6.698 6 nm),and the proportion of medium-long chain was large(millet starch B1 chain accounted for 40.91％).It was easy to form a stable double helix structure,with higher sur-face order degree(millet starch 0.76,black rice starch 0.70),and the molecular rearrangement of the two kinds of starch was more orderly and stable after retrogradation.
维普
万方数据