Biocomposite films from banana flour/halloysite nanoclay/carvacrol: Preparation, characterization, and application on capsicum (Capsicum annuum) fruits

Abstract

In this work, banana flour (BF)-based composite films were formulated by loading halloysite nanoparticles (HS) and essential oil carvacrol (CR). HS nanoclay was selected since it has abilities to improve the mechanical and water vapor barrier properties of the prepared films. CR was used since it demonstrates powerful antimicrobial activity against foodborne pathogens. Results reveal successful incorporation of HS and CR in the composite films that display an improved melting temperature (Tm) and rough surface. The water solubility of the films significantly reduced whereas the contact angle significantly improved with the impregnation of both HS and CR. The XRD diffractograms indicated pre-dominant amorphous characteristics of all the prepared films. These changes reflected well on the mechanical properties, wherein the tensile strength and Elastic modulus increased by ∼47% and ∼206%, respectively. The presence of HS and CR also reduced the films' water vapor transmission rate by about 62%. In addition, as a case study, BF/HS/CR dispersions were coated on a capsicum fruit to test their protecting ability. The incorporation of HS and CR in the BF-based biopolymeric matrix resulted in a significant reduction in the %weight loss, from 50.96 ± 2.40% (control: without coating) to 37.42 ± 3.75% (with the coating), along with an improvement in the firmness (N) from 5.04 ± 0.92 N (control: without coating) to 7.47 ± 0.25 N (with the coating), during 12 days of storage. The outcome promises BF/HS/CR based films and dispersions as natural food packaging materials to extend the shelf life of food systems.