Effect of modified atmosphere packaging assisted cold plasma on performance of edible soybean protein isolate films

The preparation of bioactive materials with good film-forming properties has become a hot research topic nowadays in recent years. In this study, an edible protein film with good mechanical and barrier properties was made from soybean protein isolate (SPI) in terms of physical modification. Specifically, the SPI was treated by dielectric barrier discharge cold plasma (DBD-CP) via modified atmosphere packaging (MAP). The effects of oxygen content in MAP on the structure SPI as well as its edible film surface microstructure, mechanical properties, barrier properties and opacity were all investigated. The results showed that the particle size of SPI gradually decreased with the increase of oxygen content. In addition, the surface of the resulting film became smoother and more detailed. At the same time, the elongation at break (EB), water vapor performance (WVP) and opacity of the edible film were significantly improved (p < 0.05). The functional properties of the edible film were most significantly improved when the oxygen content was 50%. Compared with control samples, the EB of the film and water contact angle increased by 122.60% and 47.70%, while the WVP and opacity decreased by 19.28% and 27.40%, respectively. Therefore, the MAP-assisted DBD-CP method has the potential of modification of edible protein film with good functional properties and facilitates the application of edible SPI film in various fields.