FROM WASTE TO FUNCTIONALITY: MODIFICATION OF UNRIPE MANGO STARCH BY ULTRASOUND AND HEAT

The production of mango (Mangifera indica L.) in the Santa Tereza region of the Cusco department, Peru, has increased in recent years, also resulting in increased fruit waste. This situation presents opportunities for utilizing unripe fruits as a non-conventional source of starch. Ultrasound is a physical method used to modify starch, generating local shear forces and free radicals that alter its structure and properties, and is considered a "green technology". This study aimed to evaluate the effects of ultrasonic waves on the paste properties of the Criolla variety mango starch. Native mango starch suspensions (12% m/m) were subjected to ultrasonic waves (37 Hz, 1000 W) and thermal bath (without control, 30°C and 60°C) for 5, 15, and 25 minutes, totaling nine treatments, in addition to the control sample (native mango starch). After modification, the starches were recovered by centrifugation and dried at 40°C in an air circulation oven. The paste properties were evaluated using an Anton Paar rheometer model MCR702e (10% m/m). Peak viscosity varied moderately between treatments (5780-6646 cP), while the paste temperature remained stable (67.3-70.0°C), indicating little change in the gelatinization point. Meanwhile, the breakdown, final viscosity, and setback (3703-5100 cP; 3680-5020 cP; 759-2795 cP, respectively) showed greater dispersion, suggesting differences in heating stability and retrogradation. Principal component analysis revealed that PC1, responsible for almost 88% of the variance, clearly separated treatments 8 and 9 (15 and 25 min of ultrasound at 60°C, respectively), reflecting very different rheological profiles. Treatments 3 (25 min of ultrasound without temperature control) and 5 (15 min of ultrasound and 30°C) stood out with negative values, indicating differences within the group of moderate treatments. Similarly, PC2 (8.7% of variance) showed unique characteristics of treatment 7 (5 min of ultrasound at 60°C), while the other low- or medium-intensity treatments were close to the native sample, suggesting insignificant rheological changes. The results obtained made it possible to establish a difference between the effects of ultrasonic and thermal waves on the rheological behavior of mango starch. It can be concluded that both thermal and mechanical effects can disrupt/alter the structure of starch, impacting its paste properties, with longer and higher temperature treatments causing greater changes in unripe mango starch.