乳酸对沙蒿胶-蜡质玉米淀粉混合体系的影响

Effect of Lactic Acid Content on the Mixed System of Artemisia Sphaerocephala Krasch and Waxy Corn Starch

通过动态流变检测、扫描电镜微观结构观测、低场核磁共振检测等方法,以及对粉质曲线和糊化曲线进行分析,探究了乳酸含量对沙蒿胶(Artemisia Sphaerocephala Krasch gum,ASKG)/蜡质玉米淀粉混合体系加工性能、质构性质、水分组成、糊化特性等方面的影响。结果表明,随着乳酸含量(0~5.00%,v/w)的增加,体系弱化度提高,耐揉混性降低;储能模量G’、损耗模量G’’减小;ASKG网络结构被破坏,对淀粉颗粒的包裹能力下降;强结合水消失,不易流动水弛豫时间提前,游离水占比增加;体系变得易于糊化,冷却后最终黏度下降。此外,比较了5、10 min的揉混对高乳酸含量(2.50%~5.00%)混合体系质构的影响,发现10 min的揉混使体系强度更低,黏弹性较弱,ASKG网络结构更为松散。

The effects of lactic acid content on the processing properties,textural properties,moisture composition and pasting characteristics of the Artemisia sphaerocephala?Krasch?gum(ASKG)/waxy maize starch blend system were investigated by dynamic rheological testing,scanning electron microstructure observation and low field NMR detection,as well as analysis of the powder quality curve and pasting curve.The results show that with the increase of lactic acid content (0~5.00%,v/w),the degree of weakening of the system increases and the resistance to kneading decreases;the storage modulus G’ and loss modulus G’’ decrease;the network structure of ASKG is destroyed,and the ability to wrap starch granules is reduced;the strong bound water disappears,the relaxation time of non-flowing water advances,and the proportion of free water increases;the system becomes easy to gelatinize,and the final viscosity decreases after cooling.In addition,the effects of 5 min and 10 min kneading on the texture of the mixed system with high lactic acid content (2.50%~5.00%) were compared,and it was found that 10 min kneading made the system lower in strength and weaker in viscoelasticity.The ASKG network structure is looser.