山药及零余子酸、酶处理淀粉的理化性质

利用酸和淀粉酶、糖化酶分别处理山药及零余子淀粉，利用扫描电镜、X射线衍射及流变仪等测定不同处理组淀粉的理化特性。结果表明：山药和零余子原淀粉颗粒较为完整，没有裂缝，呈卵圆形，表面光滑；酶、酸处理均会导致淀粉降解，酸处理淀粉表面破坏最为严重；零余子原淀粉、酸处理和酶处理的淀粉结晶度分别为32.02%、27.02%和31.13%，而山药原淀粉、酸处理和酶处理淀粉结晶度分别为34.32%、29.27%、33.55%。淀粉糊透光率、凝沉百分比表明零余子原淀粉最易老化，流变特性表明不同处理组的淀粉均具有弱凝胶特性。

Effect of Acid and Enzymatic Treatment on Physical and Chemical Characteristics of Starches from Yam (Dioscorea opposita Thunb.) Tuber and Bulbil

After treatment with acid, amylase or glucoamylase, starches from yam (Dioscorea opposita Thunb.) tuber and
bulbil were characterized for physical and chemical properties by scanning electron microscopy (SEM), X-ray diffraction
and rheometer. The results showed that the native starch granules from yam tuber and bulbil exhibited a complete oval
shape with a smooth surface and no cracks. Yam starches were degraded by enzymatic and acid treatments, and the surface
of acid-treated starch granules was more severely damaged. The crystallinities of native, acid- and enzymatically-treated
bulbil starches were 32.02%, 27.02% and 31.13%, respectively, while those of native, acid- and enzymatically-treated tuber
starches were 34.32%, 29.27% and 33.55%, respectively. The transmittance and retrogradation percentage of starch paste
showed that the native starch from yam bulbil could be aged most easily. Rheological characteristics illustrated weak gel
properties of yam starches.