变性对大米淀粉热膨化性质的影响

以醋酸酐、三聚磷酸钠和环氧氯丙烷为变性剂对大米淀粉进行醋酸酯、磷酸酯及交联变性,制得不同取代度的大米变性淀粉。将变性淀粉在已优化的条件下进行热膨化,以膨化率及脆度为指标研究变性对淀粉热膨化性质的影响。结果表明:与原淀粉相比3,种变性淀粉的热膨化性质均得到了改善,但交联变性的改善程度不如酯化变性的好。淀粉醋酸酯的取代度为0.083 1时,膨化率和脆度分别为9.3和0.164 kg.s;淀粉磷酸酯的取代度为0.007 7时,膨化率和脆度分别为9.6和0.166 kg.s;交联淀粉的沉降积为2.4 mL时,膨化率和脆度分别为8.8和0.168 kg.s,原淀粉的膨化率和脆度分别为7.6和0.300 kg.s。试验表明在原淀粉中添加适量的变性淀粉可以显著改善其热膨化性质。

Effect of modification on thermal expansion properties of rice starch

Modified starches with different degree of substitution obtained through acetate,phosphate and crosslinked modification were puffed under the optimal condition.Expansion ratio and crispness were used as indicators to investigate the effect of modification on thermal expansion properties of rice starch.Results showed that the esterified modification had a certain degree of improvement in expansion ratio and crispness.However the result of crosslinked starch was undesirable and inferior to esterified starch.Expansion ratio and crispness of acetate and phosphate esterified starch were 9.3,0.164 kg·s and 9.6,0.166 kg·s respectively with substitution degree of 0.083 1 and 0.007 7.Crosslinked starch with sedimentation volume of 2.4 mL showed expansion ratio 8.8 and crispness 0.168 kg·s.Expansion ratio and crispness of native starch were 7.6 and 0.300 kg·s,respectively.The experiment revealed that certain amount of modified starch could be added into native starch in order to remarkably improve its own thermal expansion properties.