不同小麦品种籽粒淀粉理化特性的差异及其相关

Differences and Correlations of Starch Physicochemical Properties among Different Wheat Cultivars

选用非糯性强筋、中筋、弱筋小麦品种和糯性小麦品种（系）,研究了淀粉理化特性的差异。结果表明,糯性与非糯性小麦RVA图谱具有明显的差异。峰值黏度、低谷黏度、最终黏度、峰值时间、糊化温度等黏度特征值,糯小麦均显著低于非糯性品种,同一类型不同品种间RVA图谱差异主要是在峰值黏度之后的曲线变化;破损淀粉含量为强筋〉中筋〉弱筋〉糯小麦。糯性与非糯性小麦品种面粉的X-衍射图谱均呈现A型特征,晶体结构差异主要表现在峰值的大小,结晶度变化范围为28.97%-36.97%。相关分析表明,直链淀粉含量、直/支比、破损淀粉含量对淀粉黏度特性有重要的影响,而结晶度对黏度特性影响不显著。

Starch physicocbemical properties include viscosity, crystallinity, gelatinization and thermal properties, which can directly or indirectly affect dough and final product qualities. Many researches showed that the correlation of starch granule size, amylose content and ratio of amylose content to amylopectin content with viscosity properties was significant. We studied starch viscosity property, damaged starch content and crystal property in different types （waxy or non-waxy） of wheat or wheat cultivars and their reciprocal relationship in Yangzhou University. Pasting properties of starch were measured by the Rapid Viscosity Analyser Super3 （Newport Co. , Australia）. Four different types of viscosity profiles were got. For strong-gluten wheat, final viscosity value was higher than peak viscosity value. For medium-gluten wheat, final viscosity value was slightly higher than peak value or almost the same. For weak-gluten wheat, final viscosity value was a little lower than peak value or almost the same. The pasting parameters of waxy wheat were lower than those of the others （non-waxy）. There was significant difference in RVA profile among different cultivars with the same type （strong-gluten, mediate-gluten, weak gluten or waxy wheat）, which induced the changes of pasting parameters after their reaching peak viscosity. During milling, some starch granules can be mechanically damaged. Different cultivars flour milled by Branbender mill had different damaged starch content, which were tested by SDmatic （Sweden）. The order of damaged starch content of wheat flour was strong-gluten wheat 〉 medium-gluten wheat 〉 weak-gluten wheat 〉 waxy wheat. X-ray diffraction of flour investigated with Diffractomes Broker Axs D8 Advance （Germany） in different wheat cultivars showed their peaks at angle 15°, 20°, 23°, 17°, and 18°, which retained the typical A-type pattern. The order of intensities of X-ray diffraction peaks was 18° 〉 17° 〉 23° 〉 15° 〉 20°, which was the main difference among them. Degree of crystallinity ranged from 28.97%- 36.97%. It might be concluded that amylose content, the ratio of amylose content to amylopectin content and damaged starch content have significant effects, while crystallinity has no significant effect on starch pasting properties.