Effects of plasma activated water (PAW) on rheological, thermal, hydration and pasting properties of normal maize, waxy maize and potato starches

Plasma-activated water (PAW), characterized by acidic pH and content of highly reactive species (nitrite, nitrate, hydrogen peroxide, ozone), was applied as a strategy to modify the structure and functionality of potato, normal maize, and waxy maize starches. PAW was generated with a corona discharge at 15 kV, 5 kHz for 1 min. Starches were mixed with PAW just after generation for 20 min and then dried. Native and PAW-treated starches were evaluated for rheological, pasting, gelatinization, and hydration properties, and subjected to Fourier-transform infrared (FTIR) spectroscopy. Results showed significant (p < 0.05) changes in almost all the considered parameters, dependent on the starch characteristics. While an increase in most pasting and rheological parameters and gel hardness was observed for normal maize and potato starches, the opposite result was found for waxy maize. FTIR results indicated significant changes in functional groups related to the ability to bind water for all starches. The results obtained in this study highlighted PAW as a promising novel and green alternative method to modify the properties of starch; however further research needs to be tailored to the specific properties of the raw material.