Research on Modification of Antimicrobial Composite Protein Films by Static Ultra-High Pressure Processing

The film-forming solution of antimicrobial composite protein-based films which whey protein and sodium caseinate were used as base materials,glycerol as plasticizer and potassium sorbate as antibacterial agent were treated with static ultrahigh pressure processing within 200~400 MPa for 5,10,20,30 minutes before curtain coating. The performance parameters of these modified films were measured respectively,such as mechanical properties,optical properties,water solubility,moisture sorption,molecular structures,barrier properties to gas and water vapor. The results showed that the surface of the films processed by ultrahigh pressure were smooth and uniform,with fewer cavities. The ultrahigh pressure processing had a significant effect on the mechanical properties and barrier properties of the films(p<0.05). When ultrahigh pressure was 300 MPa,time was 20 min the tensile strength of the film increased to 4.86 MPa,while the water vapor permeability of group C₄ decreased to 1.177×10^-9 g·cm/cm²·s·Pa,and the oxygen permeability coefficient reduced to 0.93×10^-9 cm³·cm/cm²·s·cmHg when ultrahigh pressure was 300 MPa,time was 20 min. The ultrahigh pressure processing had a significant effect on the water solubility of groups B₁,C₁ and D₄(p<0.05),which could reduce the water solubility of the films. Different ultra-high pressure processed films can meet the shelf life requirements of different foods.