Development and comparison of different polysaccharide/PVA-based active/intelligent packaging films containing red pitaya betacyanins

Betacyanin-rich red pitaya flesh extract (RPFE) was blended with different polysaccharides (chitosan, kappa-carrageenan and locust bean gum) and polyvinyl alcohol (PVA) based matrices to prepare active/intelligent packaging films. The structural, physical and functional properties of different polysaccharide/PVA-RPFE films were compared for the first time. Results showed chitosan/PVA-RPFE film, kappa-carrageenan/PVA-RPFE and locust bean gum/PVA-RPFE film had homogeneous, layered and nodular cross-sections, respectively. Betacaynins in RPFE established strong hydrogen bonds and electrostatic interactions with chitosan. However, betacaynins mainly established hydrogen bonds with kappa-carrageenan and locust bean gum. Chitosan/PVA-RPFE film was reddish brown whereas kappa-carrageenan/PVA-RPFE and locust bean gum/PVA-RPFE films were reddish purple. Polysaccharide/PVA-RPFE films had different light transmittance, moisture contents (20.22-27.54%), water vapor permeability (8.36-10.25 x 10(-11) g m(-1) s(-1) Pa-1), tensile strength (13.89-41.07 MPa), elongation at break (10.27-72.08%), pH-sensitivity and ammonia-sensitivity. When the films were stored at 4 degrees C and 20 degrees C for 21 days, locust bean gum/PVA-RPFE film exhibited the highest color stability and antioxidant stability. Mean-while, locust bean gum/PVA-RPFE film effectively indicated the freshness of shrimp when shrimp was stored at 4 degrees C and 20 degrees C. The results suggested the structural, physical and functional properties of betacyanin-rich and polysaccharide-based films were greatly affected by the type of polysaccharides.

Automated summary

This study looked at blending betacyanin-rich red pitaya flesh extract with different polysaccharides and polyvinyl alcohol matrices to create active/intelligent packaging films. The properties of the films, such as color, light transmittance, tensile strength, and water vapor permeability, were influenced by the type of polysaccharides used. Locust bean gum/PVA-RPFE film demonstrated the highest color and antioxidant stability, while effectively indicating the freshness of shrimp.