苦瓜功能稻米的淀粉理化特性分析

Variations of physicochemical properties of starch in bitter melon function rice

将导入苦瓜DNA籼稻新品种(D9)胚乳淀粉的颗粒形态、粒径分布、结晶结构、糊化、凝胶质构和分子组成等特性与受体进行了比较。结果表明,D9淀粉3μm以下的体积百分比明显增加,而9μm以上的大颗粒体积百分比减少。D9淀粉的分子有序化指标值分别为0.67和1.66,明显高于受体的0.60和1.18,但差示扫描量热分析起糊温度为65.5℃,显著低于受体的77.8℃。D9淀粉的最高黏度、最低黏度、崩解值和终黏度分别为2683.0,1074.0,1609.0,1499.5 mPa·s,均显著高于受体淀粉,而回生值(425.5 mPa·s)低于受体的463.5 mPa·s。D9淀粉的膨胀势和凝胶弹性值分别为20.01 g/g和2.69 mm,显著高于受体淀粉的,而直链淀粉质量分数、最大吸收波长和碘蓝值分别为13.33%、561.0 nm和0.16,均显著低于受体淀粉的。导入苦瓜DNA引起了籼稻胚乳淀粉的粒径组成、分子组成和结构的显著变化。

The particle morphology,particle size distribution,crystal structure,gelatinization,gel texture and molecule properties of indica rice starch of importing bitter melon DNA(D9)were compared with its receptor.The results showed that the volume percentage of D9 starch<3μm increased significantly,while the volume percentage of large granule>9μm decreased.The molecular ordering index values of D9 starch were 0.67 and 1.66 respectively,which were significantly higher than those of receptor,0.60 and 1.18;while the pasting temperature of differential scanning calorimetry was 65.5℃,which was significantly lower than that of receptor 77.8℃.The highest viscosity,the minimum viscosity,disintegration value and final viscosity of D9 starch were 2683.0,1074.0,1609.0,1499.5 mPa·s,respectively,which were significantly higher than those of receptor starch.However,the retrogradation value(425.5 mPa·s)less than 463.5 mPa·s of the receptor starch.The swelling power and gel elasticity of D9 starch were 20.01 g/g and 2.69 mm respectively,significantly higher than the receptor starch.However,the amylose content,the maximum absorption wavelength and the iodine blue value were 13.33%,561.0 nm and 0.16 respectively,significantly lower than that of the receptor starch.Importing the bitter melon DNA into rice caused of rice endosperm starch was caused the significant variations in granule size composition,molecular composition and structure of the endosperm starch.