羟丙基双淀粉磷酸酯糊液的屈服应力及触变性研究

Study on Yield Stress and Thixotropy of Hydroxypropyl Distarch Phosphate Paste

为研究羟丙基双淀粉磷酸酯(Hydroxypropyl distarch phosphate,HPDSP)糊液的屈服应力和触变性行为,本文以不同链支比的玉米淀粉(CS)和蜡质玉米淀粉(WS)为原料的HPDSP为研究对象,讨论了HPDSP糊液在不同温度条件下的临界质量分数、屈服应力及触变特性。结果表明,HPDSP在5℃时的稀溶液-半稀溶液、半稀溶液-浓溶液临界质量分数分别为3wt%和6wt%。5wt%时玉米淀粉-羟丙基双淀粉磷酸酯(CS-HPDSP)和蜡质玉米淀粉-羟丙基双淀粉磷酸酯(WS-HPDSP)的屈服应力与温度相关性较低,而6wt%时两者屈服应力随温度升高(至85℃)显著下降了69.52%和77.95%(P<0.05)。HPDSP的触变性受质量分数和温度影响,5℃时,5wt%的CS-HPDSP和WS-HPDSP几乎无触变性,6wt%时触变环面积分别为163.49和85.00 Pa/s,随温度升高至85℃,两者分别降低86.38%和92.18%。WS-HPDSP的三段式触变性测定(Three interval thixotropy test,3iTT)展示出的触变性均小于CS-HPDSP,具有较好的稳定性。综上,与CS-HPDSP相比,WS-HPDSP的屈服应力和触变性更小。本文为HPDSP在食品中作为增稠剂的实际应用提供了理论依据。

In order to study the yield stress and thixotropic behavior of the hydroxypropyl distarch phosphate(HPDSP)paste,HPDSP respectively derived from corn starch(CS)and w axy corn starch(WS)with different ratios of amylopectin were investigated.The critical mass fractions,yield stress,and thixotropic behavior of HPDSP pastes under various temperatures were studied.The results showed that,the critic al mass fractions for the transition of the HPDSP solution a t 5℃from dilute to semi-dilute,and from semi-dilute to concentrated were 3wt%and 6wt%,respectively.The yield stress of 5wt%corn starch-hydroxypropyl distarch phosphate(CS-HPDSP)and waxy corn starch-hydroxypropyl distarch phosphate(WS-HPDSP)paste both showed weak correlations with temperature.However,at 6wt%concentration,the yield stress significantly decreased(P<0.05)by 69.52%and 77.95%respectively at 85℃.Additionally,the thixotropic behavior of HPDSP was influenced by both mass fraction and temperature.A t 5℃,5wt%CS-HPDSP and WS-HPDSP showed limited thixotropy,while at 6wt%of mass fraction,the areas of thixotropic loops of CS-HPDSP and WS-HPDSP were 163.49 and 85.00 Pa/s,respectively,and decreased by 86.38%and 92.18%at 85℃,respectively.WS-HPDSP exhibited less thixotropic behavior than CS-HPDSP,and showed better stability in three interval thixotrop y test(3iTT).In conclusion,WS-HPDSP showed less yield stress and thixotropy compared with C S-HPDSP.This study provides theoretical supports for practical application of HPDSP as thickening agents in fo od products.