Understanding the impact of moderate-intensity pulsed electric fields (MIPEF) on structural and functional characteristics of pea, rice and gluten concentrates

Aim: The effect of moderate-intensity pulsed electric fields (MIPEF) was evaluated on vegetable protein concentrates from pea, rice, and gluten. Methods: Five percent (w/w) suspensions of protein concentrates (pH 5 and 6) were exposed to up to 60,000 MIPEF pulses at 1.65 kV/cm. Both structural modifications (absorbance at 280 nm, free sulfhydryl groups, FT-IR-spectra) and functional properties (solubility, water and oil holding capacity, foamability) were analyzed. Results: MIPEF was able to modify protein structure by inducing unfolding, intramolecular rearrangement, and formation of aggregates. However, these effects were strongly dependent on protein nature and pH. In the case of rice and pea samples, structural changes were associated with negligible modifications in functional properties. By contrast, noticeable changes in these properties were observed for gluten samples, especially after exposure to 20,000 pulses. In particular, at pH 6, an increase in water and oil holding capacity of gluten was detected, while at pH 5, its solubility almost doubled. Conclusion: These results suggest the potential of MIPEF to steer structure of proteins and enhance their technological functionality.