小麦籽粒A-型和B-型淀粉粒的理化特性

以小麦面粉中分离纯化出的A-、B-型淀粉粒为材料，研究其形态及理化特性。淀粉粒扫描电镜形态观察显示，小麦全淀粉中A-、B-型淀粉粒形态差异显著，分离出的A-、B-型淀粉粒无混杂。分离纯化出的A-型和B-型淀粉粒粒径范围分别为4.45~44.46 μm和0.47~11.16 μm，单位质量数量分别为1.23×10¹⁰ g^-1和6.70×10¹⁰ g^-1，直链淀粉含量分别为27.70%和22.62%。B-型淀粉粒的膨胀势较大，但糊化值明显小于A-型淀粉粒。重组淀粉中B-型淀粉粒的重量比例小于30%时对淀粉糊化特性影响很大，超过30%后，淀粉粒粒级分布对糊化特性的影响变小。

Physico-Chemical Properties of A- and B-Type Starch Granules in Wheat

A- and B-type starch granules were isolated and purified from wheat (Triticum aestivum L.) flour to study their physico-chemical properties. Starch granule image of scanning electron microscopy (SEM) showed that there was obvious morphological difference between A- and B-type starch granules, and they could be completely isolated without mixture due to the unique type of starch granule in each group. The diameter of A-type starch granule was 4.45–44.46 μm and there were 1.23×10¹⁰ granules per gram starch, whereas the two values of B-type granule were 0.47–11.16 μm and 6.70×10¹⁰, respectively. Amylose content in A- and B-type granules was 27.70% and 22.62%, respectively. Compared with the A-type granules, the B-type granules had higher pasting temperature and lower viscosities of peak, breakdown, and setback. The B-type granules contributed greatly to the pasting properties of the reconstituted starches when the fraction of B-type granules was less than 30%. Effects of starch granule size distribution on pasting property of reconstituted starch decreased when the fraction of B-type granules was higher than 30%.