Abstract
This study explores the enhancement of functionality in quinoa protein isolate (QPI) through Vacuum-cold plasma (VCP) treatment across varying pH levels (2.0-10.0). Quinoa, a gluten-free pseudocereal, is recognized for its high-quality protein content (12-23%) and favorable amino acid profile. However, its further application in food products is limited by challenges related to solubility and functional properties. Our findings revealed that VCP treatment significantly improves the solubility, dispersibility, and techno-functional properties of QPI. Specifically, solubility increased from about 4% (untreated) to 72% at alkaline pH, with dispersibility rising from 25% to 54%. Techno-functional properties exhibited enhancement, including water holding capacity (2.8-5.9%) and oil holding capacity (2.3-3.2%) at pH 10.0. Emulsifying activity index (EAI) increased to 9.24 m²/g while emulsion stability index (ESI) reached 71.6 min at acidic conditions (pH 2.0). Furthermore, the foaming capacity (FC) improved from 43.75% to 78.54% and foaming stability (FS) ranged from 8.45% to 89.65%. Additionally, particle size analysis demonstrated that VCP reduced aggregate sizes, resulting in greater surface area and hydrophilicity, thus enhancing WHC and OHC. Zeta potential indicated increased electrostatic repulsion following plasma treatment, correlating with improved emulsion stability. FTIR analysis confirmed structural alterations in QPI, highlighting increased hydrogen bonding contributing to enhanced functional properties. Overall, this research substantiates the potential of VCP as a non-thermal processing method to improve the quality and functionality of plant-based proteins, making quinoa protein a viable ingredient for various food applications catering to growing dietary preferences. Future studies should focus on optimizing VCP conditions to maximize these benefits while maintaining protein integrity.