Manothermosonication, high-pressure homogenization, and their combinations with pH-shifting improve the techno-functionality and digestibility of hemp protein

Abstract

The growing interest in plant-based proteins, particularly hemp protein, has driven the exploration of new methods to address the limitations of its industrial utilization, such as its poor functional properties. This study examined how manothermosonication (MTS) and high-pressure homogenization (HPH) techniques, along with pH-shifting, could enhance the techno-functionality of hemp protein isolate (HPI) and produce functionalized hemp protein nanoaggregates. Optimal processing conditions of MTS were 50 °C, 200 kPa, and 90 s, as determined by response surface methodology. The pH-shifting + MTS and pH-shifting + HPH treatments reduced the size of hemp protein nanoaggregates by 3.2- and 1.9-fold, respectively, compared to the untreated HPI. The changes in secondary (FTIR, CD), tertiary (SH group, fluorescence intensity), and 3D structures (XRD) confirmed modifications of treated hemp proteins. The XRD patterns showed an increase in the %crystallinity values from 21% to 29% upon the pH-shifting + MTS treatment. The combination of pH-shifting + MTS resulted in the highest solubility and digestibility, 2.1- and 1.3-fold higher than the untreated HPI, respectively, followed by the MTS-alone and HPH treatments. In addition, the emulsion properties (emulsion activity, stability, creaming index, and droplet sizes) exhibited the highest values in HPI treated by pH-shifting + MTS and + HPH. The MTS and HPH technologies provide a promising viewpoint for producing protein nanoaggregates with enhanced functional properties for microencapsulation, edible film, and other applications.