Optimization and Effect of Radio Frequency Cold Plasma on Solubility of Pea Protein Isolate

In this study, a radiofrequency-generated cold plasma (RFCP) was used to study the effect of cold plasma on the structural modification of pea protein isolate (PPI). While PPI possesses unique functional properties; the challenges associated with the functionality (the poor solubility) of PPI limit its use in different food formulations. Hence, we hypothesized that the plasma energy generated by RFCP from a mixture of gases (CO2: Ar) will lead to structural changes and thereby enhance the solubility of PPI. To prove this hypothesis, the entire experiment was conducted using a response surface methodology (RSM) design. The solubility was then determined at two pH conditions (7 and 3.4) in distilled water (DW). Experimental conditions such as power levels (0, 60, and 120W); time (10, 15, and 30 min), and flow rate of CO2: Ar (15:10, 25:10, and 35:10 sccm) of RFCP were considered explanatory variables. The results at pH 7 showed that at power level 83 W; time 29 min; and flow rate 20.5 sccm resulted in a saddle point solubility of 13.0% from 11.3 % (15.0% increase). Similarly, the results at pH 3.4 showed that at power level 68 W, time 15.5 min, and flow rate 23.6 sccm resulted in a saddle point solubility, thereby increasing the solubility to 7.0% from 5.50% (27.27% increase) for the commercial PPI. The current data shows that cold plasma could be a useful process to enhance the solubility of PPI but requires further research to obtain economically viable enhancement of plant protein ingredients.