Effect of cooling–heating rate on sol-gel transformation of fish gelatin–gum arabic complex coacervate phase

• We considered sol-gel transformation of FG-GA coacervate phase at different cooling and heating rates.
• Rheological tests were used to consider sol-gel transformation and gel properties.
• Prolongation of cooling process led to formation of more rigid coacervate gels.
• Stronger coacervate gels showed higher melting temperatures during heating process.
• All of obtained FG-GA coacervate gels were classified as a weak physical gel.

The objective of this study was to characterize influence of different cooling and heating rates on gelation of fish gelatin (FG)-gum arabic (GA) complex coacervate phase using rheological measurements. For the coacervate phase prepared at 10 °C, the gelling temperature, melting temperature, gel strength, and stress relaxation decreased with increasing cooling or heating rate, however, no gelation was observed at the highest cooling rate of 0.05 °C/min. Similar trends were obtained for the coacervates phase prepared at 30 °C, but the gelation did not occur at a cooling rate of 0.033 or 0.05 °C/min. The results indicated that rheological properties of FG-GA coacervate gels were highly dependent to the cooling process, where more thermos-stable and stronger gels formed at slower cooling. This was probably because of higher degree of molecular rearrangements, more hydrogen bindings, and formation of greater junction zones into the gel network at slower cooling rates. However, all of the FG-GA coacervate gels obtained at different cooling rates were classified as a weak physical gel.