不同处理条件对明胶体系凝胶特性的影响

Gel properties of gelatin system affected by treatment conditions

分析了明胶体系的凝冻强度、黏度和透射比在明胶浓度、蔗糖、NaCl及pH值4个不同处理条件下的变化规律。在试验范围内,随明胶浓度的增加,明胶凝冻强度呈线性增大趋势（ R2=0.993）,黏度呈二项式增大趋势（R2=0.975）,透射比呈线性减小趋势（R2450=0.972,R2620=0.971）。随蔗糖浓度的增加,明胶凝冻强度呈先增大后减小的三项式趋势（R2=0.940）,黏度呈二项式增大趋势（R2=0.970）,透射比则整体上呈增大趋势。随NaCl浓度的增加,明胶凝冻强度线性减小（R2=0.984）；黏度先减小后增大,当NaCl浓度为2.00 mol/L时,黏度最小；透射比呈先增大后减小的变化规律。pH值为4～7时,明胶体系的凝冻强度相对较高；而pH为7时,黏度最大；随pH值的增加,透射比呈先减小后微弱增大的二项式趋势。

When gelatin is added to food as a kind of food additive, the gelatin concentration , sucrose and NaCl or pH value of the food can affect the gel properties. Therefore, the study focused on the effects of different concentrations of gelatin, sucrose and NaCl, and pH value on gel strength, viscosity and transmittancy of gelatin system. As the gel concen-trations went up, the gel strength of gelatin system increased linearly（R2=0. 993）, the viscosity increased binomially（R2=0. 975）,while the transmittancy decreased linearly（R2450=0. 972,R2620=0. 971）. As the sucrose concentration climbed, the gel strength showed a trinomial variation rule of increasing first and decreasing later （R2=0. 940）, the viscosity exhibited a binomial increase trend（R2=0. 970）, and the transmittancy increased on the whole. The gel strength yielded a decreased linear relationship with the concentration of NaCl（R2=0. 984）, the viscosity decreased to the minimum by 2 mol/L NaCl and then increased, and the transmittancy was increased first and then decreased. The effect of pH value on the gel proper-ties of gelatin system was more complex. When pH value ranged from 4 to 7, the gel strength was relatively high. When pH value was below 4 or above 7, the gel strength decreased dramatically. The viscosity reached its maximum value when the pH value was 7 and reduced significantly afterwards （ P〈0. 05 ） . The transmittancy showed a decrease-increase binomial relationship with pH value.