小麦籽粒淀粉与面粉的理化特性差异

面制食品的品质与籽粒淀粉理化特性关系密切, 糯质和非糯质小麦籽粒淀粉组分有明显差别。本研究比较了糯小麦(宁糯麦1号、扬糯麦1号)和非糯小麦(扬麦16、中国春)的淀粉与面粉的黏度特性、热力学特性、膨胀势、溶解度等参数, 旨在阐明小麦籽粒淀粉与面粉的理化特性差异。4个品种籽粒淀粉粒均以C型淀粉粒(粒径<2 μm)为主, 占96.14%~97.36%, 糯小麦C型淀粉粒的比例高于非糯小麦。籽粒淀粉中破损淀粉含量低于面粉中破损淀粉含量; 籽粒淀粉的膨胀势、透光度、热焓值和回生度高于面粉, 溶解度和淀粉糊化的起始温度、峰值温度、最终温度低于面粉。与非糯小麦相比, 糯小麦面粉具有较低的破损淀粉含量、黏度参数特征值和淀粉回生度, 较高的溶解度、膨胀势、透光率和热焓值。外源添加剂试验结果表明, 面粉中α-淀粉酶活性、蛋白质与脂肪含量以及食品加工过程中添加的蔗糖和氯化钠均影响面粉的糊化特性, 是造成淀粉与面粉理化特性差异的主要原因。

Differences in Physicochemical Properties between Flour and Starch of Wheat Grain

The quality of wheat food products significantly relates to physicochemical properties of starch. Starch components are different between waxy wheat and non-waxy wheat. To realize the different physicochemical properties of flour and grain starch from waxy wheat cultivars (Yangnuomai 1 and Ningnuomai 1) and non-waxy wheat cultivars (Yangmai 16 and Chinese Spring), we tested the pasting and gelatinization properties, thermodynamic properties, swelling power as well as solubility and analyzed the differences between flour and starch. C-type granule (<2 μm) accounted for 96.14% to 97.36% of the total granules among four wheat cultivars, which was the main granule in grain starch. The number percentage of C-type granule in waxy wheat was slightly higher than that in non-waxy wheat. The damaged starch content in grain starch was also lower than that in flour. As compared with flour, grain starch had higher swelling power, transmittance, gelatinization enthalpy (ΔH), degree of retrogradation (DR%), and lower initial gelatinization temperature (T_o), peak temperature (T_p), final temperature (T_c) as well as solubility. Waxy wheat flour had lower damaged starch content, pasting property eigenvalue and degree of retrogradation than non-waxy wheat flour. The α-amylase activity, protein and lipid contents in wheat flour and the added sucrose and sodium chloride all affected the physicochemical properties of wheat flour, which is the main reason causing different physicochemical properties between wheat flour and grain starch.