From bulk banana peels to active materials: Slipping into bioplastic films with high UV-blocking and antioxidant properties

• Published in: Journal of cleaner production Vol. 438; p. 140709
• Main Authors: Silva, Rodrigo D., Pacheco, Thályta F., de Santi, Amanda D., Manarelli, Fabiana, Bozzo, Breno R., Brienzo, Michel, Otoni, Caio G., Azeredo, Henriette M.C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20.01.2024
• Subjects: Antioxidant activity; antioxidants; Banana peel; banana peels; bananas; bioeconomics; Bioplastic film; bioplastics; biopolymers; carboxymethylcellulose; contact angle; hydrophobicity; Hydrothermal pretreatment; industry; permeability; solvents; sulfuric acid; tensile strength; ultraviolet radiation; UV-Blocking; water vapor; UV-Blocking; Banana peel; Hydrothermal pretreatment; Bioplastic film; Antioxidant activity
• ISSN: 0959-6526
• DOI: 10.1016/j.jclepro.2024.140709

Bananas are among the most produced fruits globally, and their industry generates substantial amounts of peels, which are currently underutilized. Therefore, a simple process was proposed to fully convert banana peel powder (BPP) into bioplastic films using mild pretreatments. The influence of the following variables on film performance was investigated: the type of BPP (unblanched versus blanched), the pretreatment solvent (water – i.e., hydrothermal pretreatment, HTP – or sulfuric acid solution – i.e., dilute acid pretreatment, DAP), and the addition or not of carboxymethyl cellulose (CMC) in the films. The tensile properties of the bioplastics were primarily affected by the presence of CMC, with the films containing 20 wt% of this biopolymer achieving a tensile strength up to 16 MPa. The water vapor permeability was not influenced by any of the studied variables. In contrast, the water contact angle was primarily affected by the pretreatment employed, with all films prepared by HTP displaying a hydrophobic surface. The UV-shielding properties of the materials were mainly influenced by the type of BPP, and all films blocked at least 98% of UV radiation. The antioxidant activity was influenced primarily by the type of BPP, as blanching banana peels helped preserve it. These films are, therefore, promising materials for active food packaging applications, which could contribute to a transition toward a circular bioeconomy. [Display omitted] •Bulk banana peels were fast pretreated to produce bioplastic films.•Incorporating carboxymethyl cellulose enhanced the tensile film properties.•Banana peel films exhibited excellent UV-shielding properties.•Boiling banana peels in citric acid solution prevented loss of antioxidant activity.•Antioxidant activity remained strong in banana peel bioplastic films.