Performance optimization of soy and whey protein isolates as coating materials on chicken meat.

To determine the optimal coating performance of soy protein isolate (SPI) and whey protein isolate (WPI) on chicken meat, the effects of SPI (0 to 10%), WPI (0 to 10%), and pH (3 to 8) on coating pickup, frying loss, yield, moisture, and fat content of chicken meat were investigated by response surface methodology. Chicken breast meat samples were dipped in protein solutions with different pH and then drained. Subsequently, they were coated with a dry commercial coating mixture, and the coated samples were deep-fat fried in margarine. Soy protein isolate had better performance on chicken meat than WPI. The performance increased significantly at higher pH values. Optimal responses were the minimum for coating pickup, yield, and moisture content and the maximum for frying loss and fat content. Critical values for the optimal responses were between 5.05 and 5.80 pH, 2.74 and 4.65% SPI, and 3.10 and 4.74% WPI, respectively. However, the optimal breading performance combination was 7.13 pH, 9.0% SPI, and 0.6% WPI.