Preparation, properties evaluation, and application in strawberry preservation of multi-functional arabica coffee husk pectin polysaccharide-cinnamaldehyde edible composite film

Abstract

With the growing global coffee consumption and production, the by-product coffee cherry husk has significantly increased, posing environmental concerns and challenges regarding its comprehensive utilization. Our previous study has shown that arabica coffee husks are rich in pectin polysaccharides (CP) and exhibits excellent film-forming properties. Nevertheless, the CP application in encapsulating active compounds for preserving perishable fruits remains underexplored. This study focused on the development of films (CPF), which was loaded with different concentrations (0, 0.5, 1, 1.5, 2, and 2.5 %, v/v) of cinnamaldehyde (CIN) on the CP and their application in strawberry preservation. The results showed that all the CPF film-forming solutions possessed excellent film-forming properties and antibacterial effects. CP and CIN jointly altered the microstructure of the CPF samples, enhancing their barrier properties, mechanical, antioxidant, and antibacterial properties. Among them, the CPF-1.5 group demonstrated the most outstanding comprehensive characteristics. The antibacterial mechanism experiments have confirmed that it could alter bacterial cell membrane permeability by binding to the amino acid residues of membrane receptors via CIN to form stable complexes. CPF films also exhibited exceptional biosafety and the ability to degrade in soil. In addition, it could extend the shelf life of strawberries by 4 days while preserving their color and firmness and enhancing their flavor profile (microbial load < 1 ×10² CFU/g) at ²5 °C and 55–60 % relative humidity. The findings demonstrated a dual advantage: it not only enhanced the comprehensive utilization of coffee by-products but also indicated that CP hold significant potential for preserving perishable fruits.