Determination of Whey Proteins structural and functional changes under Heat and Pressure

Nadia Sharif ¹, Uzma Nihar ², Iqra ², Saba Zafar ³*

This study determined the understanding whey protein structural changes under heat and pressure is crucial for optimizing food processing and functional beverage production.

Abstract

Background: The effects of heat and high-pressure treatments on whey proteins and micellar caseins have been extensively studied to understand structural and functional changes. Whey protein isolate (WPI) solutions and micellar casein (MC) dispersions were analyzed to observe protein stability and denaturation under varying conditions. Methods: Samples were treated at 500 MPa at different pH levels (3.0, 5.8, and 7.0) and temperatures (from room temperature to -35°C). Protein denaturation was analyzed using spectrophotometry and SDS-PAGE, while secondary structure changes were determined using differential scanning calorimetry. Results: High-pressure treatments caused unfolding of WPI at room temperature, leading to increased surface hydrophobicity and exposed thiol groups. In contrast, low-temperature treatments showed less protein unfolding but induced secondary structural changes, especially in β-sheets. Heating whey proteins increased particle size and zeta potential, with further impacts on emulsion stability at higher temperatures. Conclusion: The application of heat and high-pressure treatments significantly affects whey protein structure, influencing their functionality in food and beverage systems. Optimal processing conditions depend on temperature, pH, and treatment duration.

Keywords: Whey proteins, Heat Treatment, High Pressure-Low Temperature, Protein Denaturation, Functional Properties

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