Tuning the pea protein gel network to mimic the heterogenous microstructure of animal protein
Yong Wang, Woojeong Kim, Rishi Ravindra Naik, Patrick T. Spicer, Cordelia Selomulya
Abstract
Non-extrusion texturization technology is essential to broaden the application of alternative proteins to advance sustainability and address the challenges of climate change. We propose a gelation technique to texturize non/low-gelling plant protein using curdlan gum, and to manipulate the gel texture by controlling thermal history. Pea protein and curdlan gum can form soft gel at 55–60 °C, but will form rigid gel at 80 °C. Isothermal incubation for up to 1 h could further develop the gel network with significantly higher storage modulus (e.g. 1.3 kPa without incubation, 288 kPa with 1-h incubation at 80 °C). Although curdlan-pea protein gels formed at 55–60 and 80 °C showed similar modulus ranges after 1-h incubation, the microstructure is noticeably different under microscopes (optical, CLSM, SEM). At 60 °C, large pea protein particles are still visible and only partially embedded into the curdlan network; at 80 °C, smaller protein particles are fully embedded into the gel network. When protein concentration increased from 4% to 8% w/w, the gel network became less organised as more space was occupied by protein particles. We demonstrated that heterogenous structures could be achieved by controlling the thermal history of curdlan-pea protein gels to mimic animal tissue with different stiffness (modulus) between the layers. This gelation technique can potentially be applied to other plant-sourced or alternative proteins without the need of an extruder.