Application of Plasma Treatment on Coliform Inactivation, Dehydration Kinetics and Quality Attributes of Powder-Form Nutraceuticals

This study was conducted to determine the performance of atmospheric cold plasma (ACP) on powder-form biological materials including wheat flour (WF) and whey protein isolate (WP). Coliform bacteria inactivation and optimization were performed based on a central composite design with two variables, namely residence time and mass of the sample. The results indicated that both variables had a significant effect on bacterial inactivation with more importance of residence time compared to mass of the substrate. The drying process was conducted for selected conditions including mild, moderate, and extreme conditions. The results indicated that plasma can even be used as a fast and effective tool for drying biological materials. Among all models used in this study, the Henderson–Pabis model was more suitable in predicting the dehydration kinetics of both materials. Drying rate constants obtained using this model indicated that the ratios of residence time over mass of the material did not have a significant impact on this parameter. Analysis of the functional properties revealed that water absorption can be highly (≈70%) enhanced in WF. However, properties such as oil absorption (in WF and WP), protein solubility and emulsifying activity index (EAI), and stability (in WP) were slightly changed by the plasma treatment.