Enhancing the techno-functionality of ultrasound-extracted dry bean starch using argon cold plasma: structural, gelatinization, rheological, and digestibility insights

Pulse starches are challenging to recover and often require characteristic modifications to expand their applicability. Ultrasound-assisted extraction enhances starch recovery from pulses while concurrently inducing structural and functional changes. However, a substantial increase in retrogradation tendency and pasting viscosities necessitates further modification. In this study, ultrasound-extracted pinto bean starch was further subjected to argon (Ar) cold plasma at varying voltages (30 to 70 kV) and durations (5 to 15 min). The results were compared to both untreated and conventionally extracted (native) starch. Cold plasma treatment modulated starch properties in a treatment-dependent manner. At lower plasma levels (30 kV for 5 -10 min, and 50 kV for 5 min), the ultrasound-induced trends were amplified. As the treatment levels increased, retrogradation tendency, swelling power, pasting viscosities, and gel strength declined, while other modifications such as increased debranching, crystalline disruption, gelatinization tendency, and solubility were further enhanced. At the higher plasma treatment levels (50 kV for 15 min and 70 kV for 10-15 min), the retrogradation, syneresis, swelling power, and pasting viscosities remained lower than in native starch. Fourier transform infrared spectroscopy confirmed that no new functional groups were introduced, indicating that the modifications were purely physical. These results suggest that Ar cold plasma can intensify ultrasound-induced modifications at low treatment levels. At higher treatment levels, it further enhances functionality while mitigating limitations such as retrogradation and viscosity, offering a promising approach for broader applications. • Argon cold plasma mitigated the limitations of ultrasound extracted starch • Plasma promoted depolymerization, crystalline disruption, solubility, and gelation • Lower plasma levels increased amylose, retrogradation, gel strength, and viscosity • Higher plasma levels reduced retrogradation and viscosity compared to native starch