Hydration effect of whey protein treated by glow discharge plasma

Glow discharge plasma (GP) was used to study the hydration mechanism of whey protein with different moisture content (10%, 20%, 30%). When the moisture content was 20%, the effect was most obvious. Strong hydration effect was confirmed by Fourier transform infrared spectroscopy (FTIR) results with sharper, narrower and blueshifted from 3283.49 cm-1 to 3286.26 cm-1, indicating the enhanced hydrogen bond. More flexible protein structure with a significant decrease in & alpha;-helix content (from 18.50% to 14.62%), & beta;-sheet content (from 29.67% to 19.38%) and crystallinity degree (from 6.18% to 0.81%) was introduced. Whey protein underwent oxidation reactions of C-C to C-O-C(H) and further to COOH, C-OH to C-O-C and sulfhydryl to disulfide bonds. The scanning electron microscopy (SEM) results showed that the treated whey protein was highly aggregated (from 55.40 & mu;m to 226.87 & mu;m) and formed porous and rough polymers. Additionally, the treated whey protein exhibited higher anti-oxidation activity, with DPPH, ABTS and OH free radicals increased by 14.55%, 11.08% and 15.56%. The water/oil holding capacity and light transmittance of whey protein was improved by 18.18%, 22.05% and 35.69%, respectively.

Automated summary

Glow discharge plasma (GP) was used to investigate the hydration mechanism of whey protein with varying moisture content. The strongest hydration effect was observed at a moisture content of 20%. Fourier transform infrared spectroscopy (FTIR) results confirmed enhanced hydrogen bonding, with a shift in signals from 3283.49 cm-1 to 3286.26 cm-1. The treated whey protein exhibited a more flexible structure, with decreased alpha-helix and beta-sheet content, as well as reduced crystallinity degree. Oxidation reactions and the formation of disulfide bonds were also observed. Scanning electron microscopy (SEM) showed highly aggregated and porous polymers. The treated whey protein displayed higher antioxidant activity, improved water/oil holding capacity, and increased light transmittance.