The synergistic effect of high pressure processing and pectin on the physicochemical stability and antioxidant properties of biopolymer complexes composed of soy protein and coumarin

This study was devoted to explore the synergistic effect of pressure level and pectin addition on the binding and structural properties of soy protein-coumarin (S-C) complexes through multi-spectroscopic approaches to elucidate the protective effect of the complexes on physicochemical stability of coumarin . High pressure processing (HPP) could reinforce the intermolecular hydrogen bonding and hydrophobic interaction between soy protein and coumarin (at a mass ratio of 3:1), resulting in the formation of complexes with smaller particle sizes and more compact structure, the effects were more pronounced as the pressure > 200 MPa. The incorporation of pectin provided a better protection of coumarin against UV and thermal degradation and improved remarkably the physical stability of complex particles during 30 days at 4 °C. In comparison with free coumarin, the coumarin retention of S-P-C (400) was up to 55.3 ± 1.7 % when exposure to UV for 120 min, 61.7 ± 2.9 % under 90 °C heating, and 96 ± 1.5 % after storage. However, the DPPH radical scavenging ability of S-C complexes decreased with HPP treatment and the addition of pectin. The present work revealed that soy protein-pectin-coumarin ternary complexes developed by HPP could be an effective delivery system for bioactive compounds with applications in functional food ingredient.