Improving functionality and texturization potential of novel pennycress (Thlaspi arvense) protein by inducing polymerization

Pennycress protein isolate (PcPI) has inferior gelation and water holding properties compared to market leader soy protein, preventing its use in food applications such as meat analogues. Therefore, this work aimed to induce polymerization of PcPI by either cold atmospheric plasma (CAP) or transglutaminase (TG) to improve functionality and texturization potential. Micro-compounding was utilized to determine bench-scale texturization potential of unmodified, CAP, and TG modified PcPI hydrated at 50% moisture. CAP treatment following dielectric barrier discharge (DBD) induced polymerization primarily through disulfide linkages. Whereas, TG resulted in a relatively higher extent of polymerization induced by disulfide linkages and other covalent interactions involving mostly cruciferin acidic subunits. Compared to unmodified PcPI, the gel strength doubled and tripled post CAP and TG treatments, respectively. TG treatment caused a significant increase in water holding capacity by 20%. Unmodified PcPI did not form fibrous structures upon micro-compounding, instead it formed a soft mass with low resilience and cohesiveness. CAP modified PcPI (PcPI-CP) had the lowest water holding properties, which resulted in a relatively hard (significantly highest mechanical energy), dense fibrous structures. Due to high gelation strength and water holding capacity, TG modified PcPI (PcPI-TG) resulted in less dense fibrous structures with more air incorporation (significantly higher void %) relative to PcPI control and PcPI-CP. PcPI-TG texturized mass had significantly higher chewiness that is desirable for meat analogues. This research, for the first time, confirmed the potential success of induced polymerization of PcPI, especially with TG, in enhancing gelation and texturization potential.