High pressure and heat-induced potato protein aggregates: A comparison of aggregation kinetics, structure modifications, and protein interactions.

Understanding the techno-functional properties of underutilized plant-based proteins, such as potato proteins, is essential in the context of the development of alternative proteins and plant-based foods. In this study, the aggregation kinetics of patatin-rich dispersions at two concentrations (1% and 4% w/w) and pH levels (6 and 7) were evaluated and compared under two physical processes: heat treatment (45 °C, 50 °C, 55 °C) and high hydrostatic pressure (400 MPa, 600 MPa). Distinct patterns in patatin aggregation were observed based on the processing and physicochemical conditions. Under all processing conditions, larger aggregates were formed at pH 6. Heat treatment led to either a slow or rapid gradual increase in aggregate size at the different pH and protein concentrations, while high-pressure-generated nanoaggregates displayed pH and pressure-level dependent kinetic behaviors. Some micro, sub-micron and nanoaggregates were then selected and characterized in terms of denaturation yield, molecular structure, and protein interactions. High-pressure treatment induced a significant reduction in protein intrinsic fluorescence intensity suggesting irreversible partial protein unfolding, irrespective of pressure or pH. The highest pressure level (600 MPa) led to significantly higher denaturation, regardless of pH. Similar trends in secondary structure modifications were observed for the different treatment conditions and were characterized by an increase in β-sheet content and a reduction in α-helices. The structural changes in the high pressure-treated samples were particularly influenced by pH. This study provides a deeper understanding of potato protein behavior under different treatment conditions, which may contribute to the design of novel plant-based protein nanostructures.