Researchers from Mahidol University in Thailand have developed a green approach for manufacturing packaging film for fruits and vegetables derived from pineapple stem starch (PSS).

To reduce the food packaging industry’s reliance on plastic, the team turned to PSS with its elevated amylose, or resistant starch, content.

The team developed film from PSS in both pure form and different types combined with glycerol to enhance the film's flexibility and pliability.

X-ray diffraction and water contact angle measurements were used to analyze the new films. These tests revealed that all versions of the film — in both pure form and mixed with varying amounts of glycerol — demonstrated different degrees of crystalline structure, which enabled the films to resist water penetration. This reportedly makes the films ideal for moisture protection applications.

Further, in those versions of the film where glycerol content was greatest, the researchers discovered that the tensile modulus and strength of the films decreased, while there was a simultaneous increase in the rate of gas transmission.

Ultimately, the researchers observed that the PSS films decelerated the natural ripening process of bananas, thereby showing promise for extending the shelf life of perishable produce.

An article detailing the team’s findings, “Toward a Circular Bioeconomy: Exploring Pineapple Stem Starch Film as Protective Coating for Fruits and Vegetables,” appears in the journal Polymers.