籼米凝胶的应力松弛特性研究

Stress-Relaxation Properties of Indica Rice Gel

以16种籼型稻米为原料制作大米凝胶,研究凝胶的应力松弛特性,籼米主要化学成分对松弛特性的影响,为大米质凝胶食品的加工和品质控制提供试验数据.结果表明,籼米凝胶的应力松弛过程主要由高弹松弛和普弹松弛2部分组成,以高弹松弛为主.籼米凝胶的普弹模量E0为1.472～11.400kg·f/m2;高弹模量E1为988～6 955 kg ·f/m2;松弛时间T为0.129 ～0.220 s;应力松弛非线形指数n为0.057～0.162;黏滞系数η为217.777～927.102 kg·f·s/m2.籼米凝胶的应力松弛特性与化学成分有关.直链淀粉诱导高分子链间产生较多的氢键,脂肪与淀粉分子结合增加分子链间交联度,导致凝胶的硬度增大、弹性减小、应力松弛衰减速度缓慢.

The rice gel produced from 16 various types of indica rice have been studied on their stress relaxation properties in the paper. The effects of the main chemical composition on relaxation parameters have been also researched to provide experimental data for starchy gel food＇ s quality and processing properties. The stress relaxation process of indica rice gel included high elastic relaxation and general elastic relaxation with high elastic relaxation as the main factor. The data were as follows： general elastic modulus （E0） of 1.472 - 11.400 kg · f/m2, the high elastic modulus （ E1 ） of 988 - 6 955 kg ·f/m2, the stress relaxation time of 0. 129 - 0. 220 s, the nonlinearity expo- nent （n） of 0. 057 -0. 162, and the viscosity coefficient （n） of 217. 777 -927. 102 kg· f· s/m2. The results showed that there was a dependence on the main chemical compositions. The higher content of amylose induced to form stronger hydrogen bonds between polymer chains ; meanwhile, the higher content of fat and starch molecules induced to the higher cross the smaller elasticity and linking slower degree between molecular chains. Both of those could cause higher gel hardness, speed of attenuation of stress relaxation.