Modulation of physicochemical attributes and functionalities of chitosan via cold atmospheric pressure plasma

This study was aimed to investigate the effect of cold plasma on chitosan powder properties at two different power levels (22 kV and 25 kV) and four different times (0, 4, 8, and 12 min). The treated and control chitosan powder were analyzed to determine any changes in their physicochemical, structural, functional, and thermal properties. The plasma treatment notably reduced the moisture content of the sample. Increasing the plasma voltage and exposure time resulted in an increase in solubility (2.42% and 5.02%, respectively) and water binding capacity (4.09% and 8.45%, respectively) of the samples. However, there was a decrease in fat binding capacity of approximately 5.41% and 5.09% (p < 0.05) under the same conditions. The plasma treatment markedly reduced the average molecular weight of chitosan samples, with the control having the highest molecular weight (1543.16 kDa) and the sample treated at 25 kV for 12 min showing the lowest (1511.21 kDa). Although there was no observed change in the functional group of the control and treated chitosan powder, the X-ray diffractometer and scanning electron microscopy analyses indicated an increase in crystallinity. Furthermore, the differential scanning calorimetry analysis of the control and treated chitosan showed that the treated samples exhibited lower melting and decomposition enthalpies. This study’s results demonstrate that cold plasma can serve as an eco-friendly method, due to its reduced chemical usage, for effectively altering the functional properties of chitosan. This opens up possibilities for a wider range of applications in both the food and polymer industries.