Effect of Addition of Soy Protein Isolate on the Gelation Properties of Low-salt Wooden Chicken Breast Meat Batter

The purpose of this work is to study the effect of addition of soy protein isolate (SPI) at 0%, 1% and 2% on the gelation properties of low-salt and normal-salt (1% and 2%, respectively) wooden chicken breast meat batters. Normal chicken breast meat batter was set as a control. Textural properties, color characteristics, cooking loss, water distribution and secondary structure of heat-induced gels from chicken breast meat were measured. The results indicated that different NaCl contents had more significant effects on the heat-induced gel hardness and cooking loss of wooden breast meat than normal meat. No significant variation in gel harness was found between wooden chicken meat batter with 2% SPI and normal meat batter without added SPI (P > 0.05), whereas addition of 2% SPI caused a significant decrease in gel whiteness (P < 0.05). Meanwhile, the T₂₂ relaxation time of immobile water of both wooden and normal meat batters was shorten (P < 0.05) by salt or SPI addition. Despite barely affecting protein secondary structure in normal meat, SPI led to conformational transformation of proteins in wooden chicken breast from an ordered (α-helix and β-sheet) to a disorder state (β-turn and random coil). In conclusion, addition of SPI can improve the textural properties and water-holding capacity of low- and normal-salt wooden breast meat batters by modifying protein structural properties and promoting water retention in heat-induced protein gels.