摘要
研究从鸡骨中提取的明胶的流变性质。结果表明:质量分数为0 .5 %的鸡骨明胶溶液为塑性流体,其流动需要克服一定的屈服应力,屈服应力的大小受温度影响,温度越高,屈服应力越小;当剪切应力大于屈服应力时,粘度基本不随剪切速率变化,表现出牛顿流体的流动特征;温度越高,鸡骨明胶溶液粘度越小,温度对其的影响符合Arrhenius模型,流动活化能为1 9.5 8kJ/mol;鸡骨明胶的粘度随质量分数的增加呈指数递增;鸡骨明胶的粘度受pH值影响,在等电点9附近,鸡骨明胶溶液的粘度最小,偏离pI则粘度增大;鸡骨明胶的粘弹性强烈受温度的影响,质量分数为3%的鸡骨明胶从粘性为主的溶胶体系变成以弹性为主的凝胶体系的转变温度(胶凝点)为2 3.6℃,而凝胶转变成溶液的转变温度(溶点)为33.6℃。适当质量分数及在室温条件下,鸡骨明胶主要表现为弹性体。
The rheological properties of chicken bone gelatin were studied. The results showed that 0.5% concentration of chicken bone gelatin solution behaved as plasticity liquid which needed to conquer bend stress to flow. The bend stress decreased with higher temperature. Viscosity of chicken bone gelatin didn't change with shear rate behaved as Newton liquid when shear stress exceeded bend stress. The decrease of viscosity with increasing temperature was followed the Arrhenius equation and the activation energy was ~19.58 kJ/mol. The relationship of viscosity and concentration was approximately logarithmic. The viscosity was affected by pH which had the lowest value around pH 9 and higher value apart from pH 9. The viscoelasticity was affected by temperature . The gelling point and melting point of 3% concentration of chicken bone gelatin were 23.6 ℃ and 33.6 ℃, respectively. Suitable concentration of chicken bone gelatin behaved as elastomer at surrounding temperature.
出处
《食品与机械》
CSCD
北大核心
2005年第1期1-3,42,共4页
Food and Machinery
