Development of a novel strategy for controlled release of lysozyme from whey protein isolate based active food packaging films

Abstract

a b s t r a c tThe purpose of this study is to develop a novel controlled release system based on pH-responsive polyacrylic acid (PAA)/lysozyme (LYS) complexes incorporated within a hydrophilic whey protein isolate (WPI) film matrix for active food packaging applications. Complex formation is simple under benign conditions that are suitable for preserving antimicrobial activity of the lysozyme. In addition, the pHdependent charge density of complexes allowed a uniform distribution in the matrix. The properties of the complexes such as size, surface charge and hydrophilicity were varied by changing PAA/LYS ratio (0.1 and 0.3 w/w) and PAA molecular weight (2 kDa and 450 kDa). The effects of complex properties as well as mode of lysozyme incorporation into the films (100%-free, 50%-freeþ50%-PAA/LYS complex and 100%-PAA/LYS complex) on the LYS release rate, activity and antimicrobial efficacy of the films were investigated. The results have shown that~100% LYS loading into the complexes is possible regardless of PAA molecular weight or PAA/LYS ratio. Incorporating lysozyme into the film in complexed form extended its release time from less than 24 h up to 500 h and reduced its diffusivity from~10 À9 tõ 10 À13 cm 2 /s. The films including 50%-free-LYSþ50%-PAA/LYS complex showed a 5.7 log reduction in bacterial population within 72 h whereas 100%-free-LYS containing film could not suppress Listeria innocua growth after 24 h. Overall, the results suggest that complexation of lysozyme with weak polyelectrolytes can be used as an effective strategy to achieve a long-lasting antimicrobial effect and that films prepared with such complexes have great potential as food packaging materials.

Characterization of whey protein-based films incorporated with natamycin and nanoemulsion of α-tocopherol

“…The whey proteins have been of great interest because, at present, the world manufacture of cheese whey annually is around 1.8-1.9 Â 10 8 tons (Zhou et al, 2019). The predominant proteins in whey are α-lactalbumin and β-lactoglobulin, with a high nutritional value representing about 50% and 20% of the total protein content, these proteins can form emulsions, foams, gels, and a high potential to form biopolymer-based materials for food applications (Ghadetaj et al, 2018;Ozer et al, 2016;Schmid et al, 2018;Shokri and Ehsani, 2017). The packaging materials made with these proteins are also edible and biodegradable, presenting an excellent barrier to gases compared with conventional plastics (Oymaci and Altinkaya., 2016).…”

Effect of nisin and lysozyme on bacteriological and sensorial quality of pasteurized milk

“…Lysozyme is a GRAS natural antimicrobial protein, widely distributed in livestock and plants and used for food preservation, e.g., as food additive in milk products as it has antimicrobial activity [11,12]. It is used to extend the shelf-life and enhance the quality of various cheese types such as mozzarella, Buratta, and Coalho [13–15].…”

Protein‐based natural antibacterial materials and their applications in food preservation

“…7 ). Whey protein‐based antibacterial film also has excellent results toward the growth of microorganisms as it provides good polymeric matrices for the antimicrobial agents to emit the active compounds into the packaging system (Ozer et al ., 2016 ).…”