Techno-functional properties and structural changes of pork myofibrillar protein with faba bean protein isolate at various pH levels.

OBJECTIVE: This study was performed to evaluate the effect of faba bean protein isolate (FBPI) on the techno-functional properties and the structural changes of the pork myofibrillar protein gels (MPGs) under various pH conditions. METHODS: Control (without FBPI) and FBPI-added treatments with pH adjusted to 6.00, 6.25, or 6.50 were prepared: control groups (C6.00, C6.25, and C6.50) and FBPI-treated groups (F6.00, F6.25, and F6.50), respectively. The experimental analysis included cooking yield, gel strength, protein surface hydrophobicity, sulfhydryl group, electrophoretic protein profile, and microstructure to evaluate the techno-functional properties and structural changes in the protein matrix. RESULTS: Cooking yield and protein surface hydrophobicity increased with pH; values were higher in C6.50 (91.3% and 31.3 μg) than in C6.00 (86.9% and 26.9 μg). Shear stress values remained consistent among FBPI-treated groups, whereas those of the control groups tended to increase with the adjusted pH level. Electrophoretic protein profiles revealed two distinct bands at 42 and 50 kDa in FBPI-added treatments, which were absent in the control groups; the intensity of these bands increased with the pH level. The F6.50 group presented a more compact three-dimensional protein network, and the increased intensities of the 42-50 kDa bands, corresponding to 7S and 11S globulins, correlated with the structural compaction of the gel matrix. CONCLUSION: FBPI improved the techno-functional properties of MPGs, regardless of the adjusted pH levels. In addition, the incorporation of FBPI into MPG was associated with pH-dependent structural changes in the protein and gel network, as observed by the protein profile and microstructure.