Phycocyanin as a structuring agent enhances gel properties of soybean protein isolate hydrogels: Insights into noncovalent interactions involving hydrogen bonding.

Abstract

Phycocyanin (PC) is a natural blue pigment and antioxidant derived from Arthrospira platensis with potential as a structural component in food systems. Here, SPI/PC composite hydrogels were prepared by incorporating PC into soybean protein isolate (SPI) at different concentrations. The incorporation of PC at low concentrations (0.003% and 0.015%, w/v) significantly improved the texture and rheological properties of SPI hydrogels. Notably, 0.003% PC markedly altered the microstructure of the SPI hydrogels, reducing the average pore diameter from 204.83 μm to 56.95 μm and promoting the formation of a more ordered and compact network. Isothermal titration calorimetry revealed a strong and exothermic interaction in the SPI-PC system, with an enthalpy change (ΔH) of -16.5 kcal/mol. Combined with Fourier transform infrared spectroscopy, these results indicated that SPI-PC association involved noncovalent interactions, including hydrogen bonding. Furthermore, the water-holding capacity of the SPI/PC hydrogels increased to approximately 99%, and they exhibited lower water loss during five freeze-thaw cycles. Overall, this study demonstrates that PC can enhance the textural and hydration properties of SPI hydrogels, highlighting its potential as an effective structuring agent for SPI-based gel systems.

Abstract as supplied by the indexing source. © the authors / publisher.