Cladode Age Enhances the Application of Mucilage in the Production of Biopolymeric Films

Abstract

This study aimed to understand how cactus age affects the physicochemical and technological properties of mucilage and biopolymeric films. Cladodes of Nopalea cochenillifera (MIU) and Opuntia stricta (OEM) were harvested at 9 months (young) and 18 months (old) of age. The epidermis was removed, aquiferous parenchyma crushed and mixed with ethyl alcohol (2:3). After homogenization, mucilage was dried, pulverized and analysed physicochemically. The powder obtained was hydrated, and a plasticizer was added, resulting in the formation of polymeric films after 24 h of drying in an oven. The produced films were characterized for physicochemical, optical, structural, mechanical and thermal properties. Older cladodes presented a higher mucilage yield (3.16%), as well as higher pH (5.26) and phenolic compounds (249.82 mg 100 g−1 DM), characteristics that are advantageous for incorporation into foods. Young cladodes exhibited higher levels of soluble carbohydrates (27.67 mg 100 g−1 DM), and the films derived from these cladodes were less transparent (5.75%) and less permeable (15.09 g mm m−2 d−1 kPa−1), in addition to displaying a higher water contact angle and improved thermal stability. XRD spectra and SEM micrographs showed that these films have a more crystalline and homogeneous structure, enhancing their mechanical strength (0.09 MPa). Therefore, the mucilage obtained from young cacti showed greater potential for application in biopolymeric films within the packaging industry.