Effect of heating temperature on physical, functional, and digestibility properties of Whey Protein Concentrate (WPC)

Abstract

AbstractWhey protein is a substance that is derived from the production of cheese. In its native form, whey protein has problems in its application in food products because it can cause a hard texture that affects sensory acceptance. It is necessary to modify the functional properties of whey protein so that it can be used more widely in the food industry. One of the modifications of whey protein is the heating treatment. The process was carried out by preheating at 70, 80, and 90°C. Then centrifuged for 15 minutes at 6000 rpm, then dried the solids using an oven vacuum at 50°C with a pressure of 25 inHg. The functional properties tested in this study were microstructure morphology, solubility, gel texture, voluminosity, and protein digestibility. The morphology of WPC powder produced significant differences between native and heating treatment. The microstructure results using TEM showed that the shape of native WPC was spherical and porous, while the heating treatment was flake-shaped. In terms of particle size distribution, native WPC and 80°C treatment have a bimodal pattern, while 70 and 90°C treatment have a unimodal pattern. As the heating temperature increases, the protein solubility will be getting lower. The lowest solubility was obtained at 90°C (16.04 ± 0.74%). Hardness produced in the gel with heating temperature significantly different than the native with the decreasing pH, the hardness produced will be higher. The fastest acidification rate produced until the final pH of 4.4 was at 80 and 90°C (270 minutes), which was faster than native (295 minutes). The heating treatment increase significantly differently in voluminosity than the native. Protein digestibility resulted in a significant difference between native and 80°C, where at 80°C (30.76 ± 0.07%), protein digestibility was higher than native (27.38 ± 0.09%).