pH-sensitive and antibacterial films developed by incorporating anthocyanins extracted from purple potato or roselle into chitosan/polyvinyl alcohol/nano-ZnO matrix: Comparative study

pH-sensitive and antibacterial films based on chitosan/polyvinyl alcohol/nano-ZnO (CPZ) containing anthocyanins extracted from purple potato (PPE) or roselle (RE) were developed. When incorporated with PPE or RE, the moisture contents and flexibility of film significantly reduced (P < 0.05), while mechanical resistance of film was significantly enhanced (P < 0.05). Water vapor permeability (WVP) of film was slightly influenced by the addition of PPE or RE (P > 0.05). CPZ-RE film exhibited darker color and lower light transmittance than CPZ-PPE film at the same incorporation level. CPZ-PPE and CPZ-RE films exhibited distinguishable color changes in different pH buffer solutions. CPZ-PPE films exhibited higher antibacterial activity against Escherichia coli and Staphylococcus aureus than CPZ-RE films. Moreover, film could effectively monitor spoilage degree of shrimp when film changed from purple to light-green. Our results suggested CPZ-PPE and CPZ-RE films have promising potential as active and smart packaging materials for applications in food industry. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

pH-sensitive and antibacterial films were developed based on chitosan/polyvinyl alcohol/nano-ZnO containing anthocyanins extracted from purple potato or roselle, showing distinguishable color changes in different pH buffer solutions and promising potential as active and smart packaging materials for applications in food industry.