Propylene glycol alginate-based film activated by Spirulina (Arthrospira platensis) powder: Physicochemical,
Li Li1, Ya Zhao1, Mohammad Molaveisi1
1School of Agricultural Engineering and Food Science, Shandong University of Technology, Xincun West Road, Zibo, Shandong Province, 255000, PR China.
Abstract:
The insufficient barrier performance, inferior mechanical properties, and lack of functionality of pure propylene glycol alginate (PGA) films limit their applications. Spirulina possesses remarkable antioxidant and antimicrobial properties. Herein, composite films were fabricated by incorporating varying concentrations (0-6 %, based on PGA weight) of Spirulina coarse and superfine powders into PGA matrices. The results showed that PGA and Spirulina powders formed composite films with improved structural integrity through hydrogen bonding interactions, as well as enhanced crystallinity and thermal stability. The addition of both coarse and superfine Spirulina powders resulted in increases in film thickness (ranging 0.052-0.070 mm) and water contact angle (73.50-88.08°), while reducing moisture content (ranging 22.72-67.00 %) and water solubility (18.68-47.02 %). The composite films activated with the superfine powder demonstrated superior barrier properties against water vapor and oxygen, as well as improved mechanical performance. The release behavior of phycocyanin and chlorophyll from PGA-based films was influenced by the concentration of Spirulina powder and the type of food simulant used. Additionally, incorporating Spirulina powder at concentrations ranging from 2 % to 6 % significantly increased radical scavenging activities by 6.30- to 15.53-fold for DPPH and 9.06- to 17.74-fold for ABTS compared to the pure PGA film. Moreover, PGA/Spirulina composite films demonstrated notable inhibitory effects against Escherichia coli and Staphylococcus aureus, with inhibition zones measuring from 9.75 to 12.50 mm and 10.50 to 12.00 mm, respectively. Overall, the PGA/Spirulina composite film enriched with 6 % superfine powder was considered the optimal formulation, owing to its excellent water vapor and oxygen barrier properties, enhanced mechanical strength, and superior antioxidant and antimicrobial functions. This study highlights the potential of PGA/Spirulina composite films as active and sustainable materials for food packaging.
