玛咖淀粉与马铃薯、淮山药淀粉的理化性质比较

Comparison of the Physicochemical Properties of Maca Starch with Those of Potato and Chinese Yam Starches

以马铃薯和淮山药淀粉为对照,研究了玛咖淀粉的化学组分、颗粒形貌、结晶结构、热力学性质、溶解度、膨胀度、糊透明度和冻融稳定性。结果表明,玛咖淀粉颗粒呈现椭圆形或不规则形,颗粒长轴在7.2-15.6μm之间,短轴在5.1-9.8μm之间;其偏光十字呈现垂直交叉,X-射线衍射结晶结构为C型,且在衍射角（2θ）为20°附近有直链淀粉-脂类复合物的特征吸收峰。玛咖淀粉的颗粒形貌和结晶结构与淮山药淀粉相似。玛咖淀粉的糊化温度较马铃薯和淮山药淀粉低,该淀粉糊化的起始温度（To）、峰值温度（Tp）和终止温度（Tc）分别为46.88℃、50.42℃和54.82℃,糊化焓变7.37 J/g。玛咖淀粉的溶解度和糊透明度比淮山药淀粉高,比马铃薯淀粉低;其峰值黏度与山药淀粉相近,显著低于马铃薯淀粉;膨胀度和冻融稳定性均优于马铃薯和淮山药淀粉。玛咖淀粉作为一种淀粉新资源,具有一定的开发价值和广阔的发展前景。

Chemical composition,particle morphology,crystal structure,thermodynamic properties,solubility,degree of expansion,paste clarity,and freeze-thaw stability of maca root starch were compared with those of potato and Chinese yam starches.Maca starch granules were oval or irregular.The long axis of these granules ranged between 7.2 and 15.6 μm and short axis ranged between 5.1 and 9.8 μm.A square cross was observed for the polarization cross of maca starch.X-Ray powder diffraction showed that maca starch had C-type crystalline patterns,and the characteristic peak of amylase-lipid complexes occurred at approximately 2θ（i.e.,approximately 20o）.Morphology and crystalline pattern of maca starch were similar to those of Chinese yam starch.Gelatinization temperature of maca starch was lower than that of potato and Chinese yam starches.Onset（To）,peak（Tp）,and conclusion temperatures（Tc） of maca starch were 46.88 ℃,50.42 ℃,and 54.82 ℃,respectively.Gelatinization enthalpy of maca starch was 7.37 J/g.Solubility and paste clarity of maca starch were higher than those of Chinese yam starch and lower than those potato starch.Peak viscosity of maca starch was similar to that of Chinese yam starch but was lower than that of potato starch.Swelling power and freeze-thaw stability of maca starch were higher than those of Chinese yam and potato starches.As a new starch source,the maca starch has certain values and broad prospects for development.