Effects of ultrahigh magnetic field on the structure and properties of whey protein

Abstract

Whey protein is an important protein supplement and its physical properties are being modified to meet various food and other related applications needs. In this study, we investigated changes of the physical and chemical properties of whey protein after treatment with ultrahigh magnetic fields (UMF) (5, 10, 15 and 20 T). We found UMF treatment induced more ordered structures with significant decrease in α-helix content (from 18.73% to 15.77%) and increase in β-sheet content (from 11.70% to 17.49%). UMF treatment caused the C–C bonds to be oxidized to C–O–C(H) and further oxidized to COOH, the N–CO groups to be oxidized to COOH, and the SH groups to be oxidized to SS. When the UMF strength was 10 T, these effects were the most significant. After treatment with UMF at 10 T, highly aggregated polymers were formed, which were 36 times larger in particle size (37.92 μm in diameter) than that of the untreated sample. The crystallinity degree of whey protein was increased to 28.78 ± 0.47. Additionally, the treated polymer exhibited higher anti-oxidation activity, better foaming capacity/stability, enhanced water/oil absorption capacity and higher emulsification capability. Therefore, UMF treatment of whey protein showed great potential in food processing and treatment.