Effect of atmospheric pin-to-plate cold plasma on oat protein: Structural, chemical, and foaming characteristics

• Published in: International journal of biological macromolecules 2023-07, Vol.242 (Pt 3), p.125103-125103, Article 125103
• Main Authors: Eazhumalai, Gunaseelan, Kalaivendan, Ranjitha Gracy T., Annapure, Uday S.
• Format: Article
• Language: English
• Subjects: Aggregation; Cold plasma; Foaming; Functional properties; Oat protein
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2023.125103

The impact of novel pin-to-plate atmospheric cold plasma was investigated with input voltage (170 V, 230 V) and exposure time (15 & 30 min) on oat protein by studying structural (FTIR, circular dichroism (CD), UV–vis, Fluorescence), morphological (particle size analysis, SEM, turbidity), chemical (pH, redox potential (ORP), ζ potential, carbonyl, sulfhydryl, surface hydrophobicity), and foaming characteristics. The plasma treatment reduced the pH while increasing the ORP of the dispersions. These ionic environment changes affected the ζ potential and particle size leading to the formation of larger aggregates (170–15; 230–15) and distorted smaller ones (170–30; 230–30) as confirmed by SEM. The FTIR spectra showed reduced intensity at specific amide bands (1600–1700 cm−1) and also an increase in carbonyl stretching (1743 cm−1) representing oxidative carbonylation (increase in carbonyl content). Thus, the partial exposure of hydrophobic amino acids increases surface hydrophobicity. The altered secondary structure (rise in α-helix, decrement in β-sheets and turns), and tertiary structures were observed in circular dichroism (CD) and UV absorbance and fluorescence characteristics of proteins respectively. Furthermore, the increase in free sulfhydryl content and disulfide content was highly affected by the plasma treatments due to observed protein unfolding and aggregations. Besides, the increased solubility and reduced surface tension contributed to the improved foaming characteristics. Thus, plasma processing influences protein structure affecting their characteristics and other functionalities. [Display omitted] •Plasma-induced pH & ζ potential reduction caused protein aggregation.•Plasma induced oxidation resulted in peptide cleavage and increased CO, F-SH.•Cold plasma increased solubility and reduced surface tension caused better foaming.