The morphology of wheat starch granules with different damaged starch (DS) content was analyzed using a particle size analyzer and scanning electron microscopy (SEM); the granular structure was studied using FT-IR spectroscopy and X-ray diffraction (XRD); and the granule–water interaction was evaluated by thermogravimetric analysis (TGA) and dynamic vapor sorption (DVS). The increase in the level of DS shifted the population of B-type granules towards larger particle diameters and shifted the population of A-type granules towards smaller particle diameters. The appearance of the surface of the starch-damaged granules was rough and flaky (SEM images). Crystallinity reductions were related to higher mechanical damage levels of the granular structure (FT-IR and XRD). Higher DS increased the liquid-water absorption capacity of the granules. Higher DS was associated with increments in less-bound water proportions and reductions in more strongly bound water proportions and related to reductions in the evaporation temperature of these water populations (TGA analyses). Concerning DVS data, the results suggested that the driving force for water–monolayer attachment to the starch granules decreased as DS increased. Therefore, it was suggested that the changes in granule structure led to a weaker water–starch polymer chain interactions due to the increase in DS. The results contribute to a better understanding of the influence of mechanical damage on the starch granular structure, which could be related to the rheological and thermal behavior of starch-based systems with different DS.

The objective of this study was to analyze the effect of different food proteins (wheat gluten, soy protein, whey protein, and ovalbumin), applied in different proportions, on the pasting and thermal properties of wheat starch using a Rapid Visco Analyzer (RVA) and Differential Scanning Calorimetry (DSC), enriching the RVA analysis with mathematical models for a deeper mechanistic understanding of the pasting behavior. Gluten and whey proteins significantly increased peak viscosity (up to +105% and +22%, respectively), while soy protein and ovalbumin decreased it (up to −16%). Conversely, the addition of all four proteins resulted in an increase in the starch pasting profile during the cooling period of the starch pastes (up to +95%). Additionally, the presence of all four proteins accelerated the starch paste formation process (0.2–0.9 min). Mathematical models showed that the addition of proteins accelerated both the viscosity decline phase (breakdown) immediately following the peak and the subsequent viscosity increase phase (setback), leading to the final viscosity. All proteins increased the gelatinization onset temperature, indicating restricted water availability for starch. Consequently, a decrease in gelatinization enthalpy was observed, most notably with ovalbumin (−28%) and whey protein (−24%). Conversely, the retrogradation characteristics showed no consistent pattern. These results offer valuable insights into managing the thermal stability of starch within diverse food applications (e.g., flour-based products) utilizing different protein sources.

This study addresses the need for sustainable and clean-label processing methods to enhance the functional and nutritional properties of sorghum flour. Reactive extrusion combining high shear forces and ozonization was selected as an environmentally friendly modification strategy. Whole and polished sorghum flours were processed using a twin-screw extruder, with ozone introduced via ozonated feed water under varying temperature profiles (140 °C and 160 °C) and moisture contents (20% and 23%). Characterization included specific mechanical energy (SME), textural attributes, water absorption and solubility indices (WAI/WSI), viscosity profiles (RVA), and surface chemistry via X-ray photoelectron spectroscopy (XPS). Finally, in vitro digestion was used to monitor the kinetics of starch and protein hydrolysis. Ozone reduced SME, increased extrudate density, and lowered expansion and fracture force, particularly in polished flour. The XPS confirmed successful oxidation, showing the conversion of hydroxyl groups into carbonyl and carboxyl groups. Ozone also improved water absorption but reduced solubility and decreased viscosity parameters in polished flour. In vitro digestion showed that extrusion ozonation enhanced protein digestibility at ~25%. At the gastric phase, ozonized whole samples showed 18.3% starch hydrolysis, and ozonized polished flour showed 8.3%, whereas non-ozonized flours exhibited ~25%. These findings prove that ozone-assisted reactive extrusion differentially changes sorghum flour properties, offering a promising approach for improved food applications.