Abstract:

Response surface methodology based on central composite design was applied to study the optimal values of critical process parameters affecting textural properties of a thermal irreversible gel, including ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature. Mathematical models were established for the elasticity, tenderness or hardness of the gel as a response value of the above parameters. The determination coefficient R2 and level of significance test for established models were 0.968 and P = 0.005, extreme significance level for elasticity, 0.976 and P = 0.002, extreme significance level for tenderness, and 0.876 and P = 0.141, insignificance level for hardness and, therefore, the models have high fitting degree and reliability. The fact that the deviations between actual values and predicted values of elasticity, tenderness and hardness were only 1.51%, 3.09% and 4.5%, respectively, demonstrates that these models can accurately describe the interactive relationships among ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature and has high usability in optimizing process parameters. The optimal values of ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature were determined to be 0.3:1, 0.06% and 90 ℃, respectively.

Key words: esponse surface methodology, thermo irreversible gel, process conditions, textural properties