Preparation and characterization of calcium-binding starch and its application in microwaveable pre-fried foods

Abstract

Pre-fried microwaveable foods are popular with many consumers because of the simplicity and speed of their preparation. However, these foods often lose their desirable crispiness after microwaving, which reduces their sensory quality and consumer acceptance. In this study, we prepared and characterized calcium-starch (CA-S) chelates and then investigated their impact on crispness retention during the microwaving of a model food (chicken nuggets). As expected, the amount of calcium bound by the CA-S chelates increased as the calcium concentration was raised. Multi-scale structural analysis of the CA-S chelates showed that calcium binding disrupted the hierarchical structure of the starch. During gelatinization, CA-S chelates exhibited a higher peak viscosity than regular starch. Adding the CA-S chelates to batter of chicken nuggets significantly improved their crispness after microwaving, without adversely affecting their color, taste, and other sensory attributes. Chicken nuggets containing 15% CA-S chelates had the highest crispness, with the value being almost 50% greater than the control group. The coating and microwave heating properties of the batter were also improved by adding the CA-S chelates. For instance, incorporating 25% CA-S chelates into the batter increased the coating “pick-up”, dielectric constant, and dielectric loss constant values by around 55%, 21%, and 20%, respectively. This increase in dielectric properties is beneficial because it enhances heat transfer to the batter during microwaving, thereby increasing the crispiness of the chicken nuggets.