Effect of cold plasma processing and ultraviolet radiation on wheat germ protein isolates: A technofunctional study

Wheat germ, a byproduct of flour production, is often underutilized despite its nutritional value. This study aimed to improve its functionality using environmentally friendly cold plasma (CP) and ultraviolet (UV) treatments in aqueous suspensions for potential food applications. Structural and chemical changes in wheat germ protein isolates (WGPI) were analyzed using FTIR and 1 H NMR. Functional properties such as water/oil holding capacity, solubility, foaming, and emulsification were evaluated. FTIR results showed that CP increased α-helix and antiparallel β-sheet structures, indicating improved structural stability, whereas prolonged UV exposure reduced ordered structures. 1 H NMR of CP-treated samples revealed intensified aliphatic signals (1.2 ppm) and aromatic peaks (6.5–7.5 ppm), suggesting oxidative modifications and formation of oxygen-containing structures. CP significantly increased water holding capacity from 1.79 to 4.18 g/g, while reducing oil holding capacity by ∼30%. Protein solubility improved across all pH values, with reduced precipitation at pH 4. Emulsification capacity increased from 33.05 to 63.36 m 2 /g at pH 10 after 30 min CP treatment, with stability reaching 298.67 min. Foamability and foam stability also improved, reaching 31.68% and 47% at pH 10. Overall, CP induced structural modifications that enhanced hydrophilicity and techno-functional properties of WGPI, highlighting its potential for sustainable food applications. • Wheat germ protein isolate was processed with cold plasma and UV radiation. • Cold plasma and UV radiation significantly altered protein’s secondary structure. • Protein oxidation was confirmed by FTIR and 1 HNMR. • Water holding capacity increased by about 4-fold after cold plasma and UV radiation. • Solubility increased by about 32% after cold plasma and UV radiation.