Temperature-Mediated Structure–Functionality Changes in Soybean Meal Protein via Extrusion

Tailoring the structure-functionality and volatile properties of pea protein isolate by high-pressure homogenization: Impact of pass number and pressure.

Pea protein is increasingly used in food formulations due to its nutritional value and sustainability. However, its limited solubility, weak interfacial properties, and undesirable off-flavors remain major constraints for broader application. In this study, pea protein isolate (PPI) was subjected to multi-stage high-pressure homogenization (HPH) at pressures ranging from 100/1000 psi to 500/5000 psi with various pass numbers (1, 2, and 3) to examine how processing intensity affects its structural, functional, and volatile properties. SDS-PAGE showed no detectable changes in molecular weight distribution, whereas FTIR, particle size distribution, and zeta potential analyses collectively indicated that HPH induced subtle physicochemical modifications in PPI. These modifications improved functional properties, particularly solubility, which increased from 83.18% in the untreated sample to 88.14% under optimized conditions. Enhancements in foaming capacity and emulsifying activity were also observed, most prominently at 500/5000 psi, although excessive processing resulted in a slight decline in foaming performance. In contrast, emulsifying stability remained largely unchanged across conditions. Furthermore, GC-MS was used to evaluate the changes in the volatile profile of PPI after HPH treatment. Seven major compounds dominated by lipid oxidation products were identified. Their relative abundances varied with homogenization conditions with pressure exerting a more pronounced influence than pass number. Overall, HPH effectively tailored the properties of PPI by reducing particle size, improving solubility and interfacial properties, and altering its volatile profile, although at higher homogenization pressures the potential trade-off between functionality and oxidative flavor stability needs to be considered.

Broccoli byproducts protein concentrate: Microwave treatment effect on functional, thermal, and structural properties.

Inspired by the exploration of underutilized byproducts to address food security concerns, broccoli byproduct protein concentrate (BBPPC) was subjected to microwave treatment to enhance its properties for broader food applications. The study examined the effects of varying power levels (270, 450, and 630 W) and a fixed processing time of 90 s on the conformation, physicochemical attributes, and functional properties of BBPPC. The findings revealed that microwave treatment led to modifications in the spatial structure of BBPPC, significantly enhancing its functional properties. SDS-PAGE showed the presence of RuBisCO (Small and large subunit), prolamin and glutelin, whereas amino acid profiling indicated transient exposure and subsequent burial of buried residues. Secondary structure analysis showed an initial decrease then increase in β-sheet content, with random coil content rising then falling, reflecting initial protein unfolding followed by refolding. Intense heating cleaved disulfide bonds into free sulfhydryl groups, which later reformed, facilitating intermolecular aggregation of BBPPC. Notably, the average particle size reduced from 647.7 nm to 336.5 nm at a power of 450 W for the specified duration. The functional properties improved significantly (p < 0.05), with a maximum water absorption capacity of 2.89 g/g, oil absorption capacity of 3.72 g/g, foaming capacity of 89.36%, foam stability reaching 58.49%, and emulsification activity index and stability index at 6.56 m2/g and 64.4 min, respectively. These results provide a theoretical foundation for the utilization of BBPPC and illustrate the effectiveness of microwave treatment in modifying plant proteins.

Modifying Structure–Functionality of Common Bean ( Phaseolus vulgaris L.) Protein via Cold Atmospheric Plasma Processing and Maillard Reaction

Structural and functional modifications of common bean (Phaseolus vulgaris L.) protein were investigated using cold atmospheric plasma (CAP) and Maillard reaction (MR) with pectin. CAP treatment (20 kV, 1–5 min) significantly enhanced protein solubility and emulsifying activity. Conversely, MR (90 °C, 0.5–3 h) reduced solubility and foaming properties but improved gelling capacity, achieving the lowest gelation concentration (LGC) at 2–3 h of heating. Conformational shifts in secondary structures (α-helix, β-turn, and β-sheet) were confirmed by FTIR and correlated with protein unfolding and structural modifications, as characterized by SDS-PAGE. Zeta potential measurements indicated that CAP improved colloidal stability, whereas extended MR heating decreased stability. These findings demonstrate that CAP is an effective nonthermal tool for enhancing protein functionality, while MR is better suited for developing stable gel-based food matrices, lowering the LGC from 8% to 5%.

Modulating the properties and structure of a wheat starch-lauric acid system via modified soy protein isolate.

Modulation of starch digestibility in ternary systems involving starch, lipids, and proteins is an emerging research area. However, native soy protein isolate (SPI) restricts the formation of wheat starch (WS)-lauric acid (LA)-protein complexes because of its rigid globular structure. Therefore, this study investigated the impact of SPI modified via pH-shift (pHS), ultrasound (US), and high-pressure microfluidisation (HPM) on the characteristics and structure of the WS-LA system. The results showed that the WS-LA-protein systems containing modified SPI exhibited increased cooling peak viscosity, higher resistant starch (RS) and slowly digestible starch (SDS) contents, and more complexes with greater short-range order than those systems containing SPI. HPM-modified SPI increased SDS content in the WS-LA-protein systems by 41.0%, promoted denser complexes, increased relative crystallinity by 21.4%, and enhanced short-range order compared with SPI. These findings provide a theoretical basis for formulating functional foods with controlled starch digestibility.

Effect of Extrusion Processing on the Instant Properties and Structural Characteristics of Yellow Waxy Corn Flour

Instant cereal powders often suffer from poor reconstitution and caking during preparation. This study investigated the effects of twin-screw extrusion and particle-size regulation on the reconstitution properties and structural characteristics of yellow waxy corn flour. Nine extrusion treatments (140–180 °C; 12–18% feed moisture) and four particle-size fractions (40–80 mesh) were screened using caking rate and suspension stability as evaluation indices; no formal process optimization was performed. Three 60-mesh samples produced at 180 °C with different feed moisture levels were then selected as representative treatments for mechanistic characterization. Compared with native flour, the extruded samples showed lower caking, improved suspension stability, and substantially higher water absorption. SEM and DSC analyses demonstrated conversion of intact granules into a porous matrix and a marked decrease in residual gelatinization enthalpy, whereas XRD showed retention of the A-type diffraction pattern. FTIR spectra were broadly similar among samples and did not indicate formation of new major functional groups. These results connect extrusion-induced granular and thermal changes with improved hydration and provide a basis for developing clean-label instant waxy corn products without chemical anti-caking agents.

Thermal Rheology and Fibrous Structure of High-Moisture Meat Analogs with Hemp Seed Cake