Effects of TGase on the Rheological Behaviors, Structural Properties and Molecular Forces of Cowpea Protein Isolate and Cowpea Albumin Gels

The effects of TGase on hardness, water holding capacity (WHC), molecular forces, structural properties, microstructure and rheological behaviors of TGase-induced cowpea protein isolate gel (T-CPIG) and cowpea albumin gel (T-CPAG) were investigated. TGase significantly increased the hardness of gels and the most stable three-dimensional network structures were formed by adding 20 U/g and 28 U/g. Not only the non-network structure proteins of gels and free sulfhydryl groups were fewer but also the β-fold and β-angle relative contents were higher than cowpea protein isolate (CPI) and cowpea albumin (CPA). Hydrophobic interaction and the disulfide bond played main roles in the formation of T-CPIG and T-CPAG. Scanning electron microscopy and rheological properties of the gel suggested that the TGase addition significantly influenced the fundamental structure and mechanical properties of the T-CPIG and T-CPAG. Taken together, the findings shed light on the gelation mechanisms of TGase cowpea proteins.