Formulation optimization of salad dressing added with Chinese quince (Chaenomelis sinensis) juice by mixture design

This study was conducted for the optimization of ingredients in salad dressing using Chinese quince (Chaenomelis sinensis) juice. The experiment was designed according to the D-optimal design of mixture design, which included 14 experimental points with 4 replicates for 3 independent variables (Chinese quince juice 35-60%, oil 20-45%, and vinegar 5-20%). The compositional and functional properties of the prepared products were measured, and these values were applied to the mathematical models. A canonical form and trace plot showed the influence of each variable on the quality attribute of final mixture product. By the use of F-test, viscosity and color values (L, a, and b) were expressed by a linear model, while the emulsion stability and sensory characteristics (color, smell, taste, and overall acceptance) were by a quadratic model. The optimum formulations by numerical and graphical method were analogous: Chinese quince juice, oil, and vinegar of 51.05, 34.69, and 14.24% by numerical method, respectively; those of 51.01, 34.71, and 14.24% by graphical method, respectively. Optimum ingredient formulation is expected to improve use of Chinese quince juice and contribute to commercialization of high quality Chinese quince salad dressing.