In this study, the effect of pH on gel properties of large yellow croaker (Pseudosciaena crocea) roe protein isolates (pcRPIs) was evaluated. The rheological properties, moisture-distribution and microstructure of pcRPIs gels were also analyzed. The results showed that pcRPIs failed to form gels at pH 4-6, while indicated gelation profile at pH 7-9. The optimum pH for pcRPIs to form gels was pH 8 with the gel point at 84 ℃, and the G’ of the pcRPIs gel formed at pH 8 reached 535.4 Pa at the concentration of 100 mg/mL. In addition, as pH increased, pcRPIs gels had smoother surface and more continuous network structure, and the water holding ability of pcRPIs gels increased. Moreover, hydrophobic interactions were the main forces in the formation of pcRPIs gels. These results indicated that pcRPIs had potential to be used as functional materials in the food industry, especially some gel products.
I really like your methodology and especially your SEM pictures. Have you tested the gel formation, by solving the protein isolate in ionized water (e.g. the 0,6M NaCl as in your extraction process) yet? Maybe this would further enhance the gel strength.
Kind regards,
Jasmin
Thank you for your comments. As suggested, we have studied the gel formation of pcRPI dissolved in 0.6M NaCl with heating at 85℃ for 20 min. The results showed that the G' value of the gel is about 1200 Pa at 0.1 Hz, which really higher than the pcRPI gels formed at pH 7-9. To this point, the gel properties of pcRPI dissolved in 0.6M NaCl will be evaluated in the future studies.
Best regards.
