Tuning the mechanical properties of pectin films with polyphenol-rich plant extracts

The mechanical properties of pectin films enhanced with polyphenol-rich fruit extracts were investigated. The scavenging and reducing activity of plant extracts incorporated into the pectin films were determined using bench assays, and their antioxidant activity was correlated with a high presence of polyphenols, which were predominantly comprised of flavonoids and anthocyanins. The pectin films generated from the extracts exhibited a range of mechanical properties; tensile strength (4.99 MPa - 6.91 MPa), elongation at break (45.8 % - 52.3 %), and stiffness (1835 g mm(-1) - 2765 g mm(-1)). To investigate the underlying relationships between plant extract composition and mechanical properties, Projection to Latent Structures (PLS) models were developed. The PLS models revealed that extracts containing high sugar and polyphenol content increase the tensile strength and moisture content of films. The elongation at break of the films was improved or diminished depending on the profile of sugar, acids, and polyphenols in the fruit extracts. Furthermore, the structures and concentration of anthocyanins and flavonoids were identified to strongly influenced the elongation at break differences. By modifying the concentration of sugars, organic acids, and polyphenols, the mechanical properties of pectin-based films can be tuned for tailored applications as food packaging materials.

Automated summary

The mechanical properties of pectin films can be enhanced by incorporating polyphenol-rich fruit extracts. The presence of high levels of sugars and polyphenols in the extracts increases the tensile strength and moisture content of the films, while the composition of sugars, acids, and polyphenols influences the elongation at break of the films. The structures and concentrations of anthocyanins and flavonoids also play a significant role in determining the elongation at break differences. The mechanical properties of pectin-based films can be tailored for specific applications in food packaging by adjusting the concentrations of sugars, organic acids, and polyphenols.