Fabrication of pea protein gels with modulated rheological properties using high pressure processing

Abstract

High pressure processing (HPP) as a non-thermal food preservation technology has recently received growing interest in protein processing. In the present study, the impact of high-pressure level, treatment time, protein concentration, and sample pH on the pea protein gel microstructure and strength were systematically investigated, as well as the protein conformation study, and the gel rheological and dissolution tests. A minimum of 10% and 15% (w/v) protein concentration was required for self-standing pea protein gel formation under 600 MPa and 300 MPa, respectively, at ambient temperature. The pH played an important role in affecting the gel microstructures and properties using HPP treatment. Particulate gels with compact structures and high mechanical strength up to 130 kPa were obtained at pH 5 mainly stabilized by hydrophobic interactions. Whereas fine-stranded gels mainly stabilized by hydrogen bonding with good elasticity and high water-holding capacity were formed at pH 7. The pH, HPP pressure level, and duration have been modulated to prepare a series of pea protein gels to mimic the texture of jelly, pudding, and tofu products. The tunable capacity using HPP makes pea protein a potential gelling ingredient in a wide range of food applications as a substitute for animal or soy protein. Furthermore, the gels treated with pH-shifting followed by HPP showed high freeze-thaw stability with a minimum syneresis level of 15% after two freeze-thaw cycles, demonstrating their potential to be used in frozen food products. Considering the advantages such as improved nutritional quality and extended shelf life compared to thermal technologies, HPP could be a promising non-thermal technique for the fabrication of pea protein gels with tunable rheological and mechanical properties to meet consumer needs for diversified texture and sensory quality.