Abstract:

This study aimed to enhance the compatibility of polysaccharide-protein mixtures, to improve their performance
and to study the effects of various factors on gelation and gel properties. The effects of formulation variables on gel strength
and water-holding capacity of konjac glucomannan (KGM)-soybean protein isolated (SPI) mixed gels were examined.
Optimization of formulation variables was carried out using combination of single factor method and response surface
methodology. A quadratic regression model was built using KGM to SPI ratio, total concentration, KCl concentration
and Ca(OH)2 dosage as the independent variables and gel strength as the response. Results showed that the optimum
conditions for preparing the mixed gel were determined as follows: mixed gel concentration, 4.5%; KGM/SPI ratio, 3:1;
KCl concentration, 0.13 mol/L; and Ca(OH)2 dosage, 0.15%. Under these conditions, the gel strength of SPI-KGM gels was
experimentally 2.758 N, approaching to the predicted value of 2.779 N. In addition, the texture properties of the mixed gels
were analyzed before and after the optimization, and the results indicated that the optimization was reliable.

Key words: konjac glucomannan (KGM), soybean protein isolate (SPI), mixed gel, response surface methodology