The Potential of Apple and Blackcurrant Pomace Powders as the Components of Pectin Packaging Films

Abstract

This work aimed to investigate the possibility of using apple and blackcurrant pomace powders to produce biopolymer packaging films as one of the actions to minimize waste in a circular economy approach. The fragmented fruit powders of 10 µm did not form a continuous film structure, thus apple pectin at the concentration of 5% was used as a film-forming agent in combination with fruit pomace (10%) and glycerol as plasticizer (50% of pectin, 2.5 g). The pectin control films and those produced with the addition of fruit pomace differed in appearance and physical properties. The films with fruit pomace were characterized by a higher thickness and much darker color in comparison with transparent pectin films. Lightness (parameter L*) decreased from 87.24 to 21.09, and the film opacity increased from 1.03 to 17.14 A/mm, indicating the capacity of light adsorption. Fruit powder addition also affected mechanical resistance, and the films showed higher tensile strength (3.11%–6.72%) with lower elongation at break (5.11%–6.07%). Sorption and wetting analyses showed that fruit pomace-containing films had a lower capacity to absorb water. The water contact angle increased from 50.69 to 70.89°. Scanning electron microscopy (SEM) allowed us to observe significant changes in the structure related to the film composition, which affected the surface roughness and obtained a more rigid film structure.