Effect of atmospheric pressure cold plasma treatment on rheological properties of barley grains

Abstract

Barley, a globally significant cereal, is increasingly utilized in food processing due to its nutritional and functional properties. The atmospheric pressure cold plasma (ACP), an emerging non-thermal technology, offers potential for modifying grain physicochemical characteristics without the detrimental effects of heat. Barley grains were subjected to ACP treatments at different voltages (50 and 60 kV) and durations (5 and 10 min), followed by comprehensive rheological analyses, including frequency, temperature, and strain sweeps. Results demonstrated that ACP treatment led to a significant reduction in storage modulus (G′), loss modulus (G″), and complex modulus (G*), indicating weakened elastic and viscous properties compared to untreated controls. The decrease in rheological parameters was more pronounced with increased plasma intensity and exposure time, suggesting that excessive plasma treatment induces degradation and chain scission within the starch-protein matrix. Notably, the damping factor (tan δ) decreased significantly in samples treated at higher intensities, reflecting a shift toward more elastic behavior. Temperature sweep tests revealed that ACP-treated samples, particularly at higher intensities, exhibited enhanced thermal stability, maintaining structural integrity at elevated temperatures. Strain sweep analysis further confirmed the reduced rigidity and viscous dissipation capacity of plasma-treated grains. These findings highlight the potential of ACP as a tool for tailoring the rheological properties of barley, offering opportunities for the development of novel barley-based products with customized textural and processing attributes.