Enhancing fresh pear preservation with UV-blocking film coatings based on κ-carrageenan, cassava starch, and copper oxide particles

Abstract

Renewable material packs have been an alternative to traditional petroleum-based products. Thus, this work aimed to develop an active and biodegradable coating based on κ-carrageenan/starch containing copper oxide particles (CuOPs) for fresh pears. The composite material was extensively characterized. Digital images of the coatings suggested stable and highly transparent materials. The composites presented handleability and flexibility. However, only the κ75 films prepared at 75:25 κ-carrageenan/starch weight ratio containing 0, 1, 1.5, and 2% (wt/wt) of CuOPs concerning the polysaccharide content demonstrated applicability as surface coatings for fresh pears. The water vapor permeation, tensile strength, and elongation at the break ranged from 1.14 × 10−10 to 1.59 × 10−10 Pa⋅m2·s−1, 26.19–101.67 MPa, and 6.73 to 17.05 wt%, respectively. Micrographs showed composite films with slight roughness and homogenous surfaces exhibiting hydrophilic characteristics supported by water contact angle measurements (between 71 and 84°). The films were durable for approximately 90 min in an aqueous solution, with the ability to expand their mass up to 3847% (sample κ75-0). The materials were tested as coatings on fresh pears under consumption conditions. The film κ75-2 conserved the fruit for consumption over 30 days, supporting better results than the commercial poly (vinyl chloride) pack. The composite material based on κ-carrageenan/starch containing CuOPs, especially the κ75-2 composite at 2.0% (wt/wt) of CuOPs, can be applied as a surface coating for fresh pears.