Optimization of a stabilizer mixture for stirred yogurt formulation using native starch, acetylated distarch phosphate, and gelatin

The application of a stabilizer mixtures is essential for producing stirred yogurt formulation. In this study, a stabilizer formulation was optimized using native starch (A: 0-2%), acetylated distarch phosphate (B: 0-2%), and gelatin (C: 0.1-0.4%) via a D-optimal mixture design approach. pH, acidity, textural properties, viscosity, syneresis and sensory characteristics were monitored during storage. Optimization criteria focused on hardness, syneresis, and overall acceptability. Two optimum formulations exhibiting the highest desirability were produced and their observed responses were compared with predicted values. Syneresis after 28 days was predominantly influenced by ingredient type and concentration; gelatin significantly reduced syneresis, whereas both native and modified starches contributed to increased syneresis. Gelatin showed a softening effect on texture immediately post-production but induced hardness during storage, with the greatest hardness observed in samples containing 0.4% gelatin at day 28. Both starch types increased hardness throughout storage. Viscosity trends paralleled hardness, with the highest coefficient for starches. Gelatin improved overall acceptability and a significant positive interaction observed among all three ingredients (ABC). Conversely, binary interactions (AB and AC) negatively impacted sensory scores. The two optimized formulations were optimum 1 (0.998% native starch, 0.872% modified starch, and 0.129% gelatin) and optimum 2 (1.116% native starch, 0.526% modified starch, and 0.358% gelatin). Observed values for optimum 1 closely matched the predicted values, confirming model accuracy. Optimum 2 showed higher storage modulus, loss modulus and apparent viscosity compared to optimum 1. Collectively, Optimum 1 demonstrated superior overall desirability and sensory acceptance and is recommended for application in stirred yogurt.