RHEOLOGICAL INTERACTIONS BETWEEN COMMERCIAL MAIZE STARCH AND SOLUBLE PEA PROTEIN

The interactions between starches and fats are well known, but in the current search for lower-calorie foods, fat has been replaced by proteins. However, the effects of protein-only replacement of starches during the cooking and cooling stages are still unknown. The objective of this study was to use the Rapid Visco® Analyzer (RVA) and a texturometer to evaluate the rheological behavior of commercial cornstarch when replaced by different concentrations (0, 1, 5, and 10%) of soluble pea protein isolate (SPI), designated CS0, CS1, CS5, and CS10. The RVA was performed using the Standard 1 program, and gel strength analysis was performed on the paste after 24 h of cooling. The results were analyzed by Tukey's test (p>0.05). The results showed that up to 10% protein, the paste temperature was unaffected, being 75°C for all samples. In the formation of pastes, it can be seen that up to 1% of protein (CS1), this did not promote rheological changes, which occurred after 5% (CS5 and CS10) in relation to the control (CS0). The most significant effects that CS5 and CS10 presented were the decrease in peak viscosity (from approximately 4500 cp to 4200 cp) and final viscosity at 50°C (from approximately 7000 cp to 6000 cp), showing that the soluble protein influenced during the cooking of the starch, making the paste with lower viscosity at 75°C and that during cooling, the retrogradation was smaller, and after storing the gel under refrigeration for 24 h, the hardness of the paste decreased from 13 N to 10 N). This work shows the potential of using proteins to modify the rheology of starch pastes and delay their retrogradation during storage, important facts that were previously controlled by the use of fats, which can be replaced by proteins, which will maintain the same caloric value of the product and make it with better protein value.