Development and Characterization of Edible Films Based on Fruit and Vegetable Residues

Abstract

Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films.

An overview of fruit and vegetable edible packaging materials

“…In the literature, fruits and vegetables are not only mainly used as purees, but also as extracts or juices, and even waste or residues after food processing. Andrade and others 44…”

“…In the literature, fruits and vegetables are not only mainly used as purees, but also as extracts or juices, and even waste or residues after food processing. Andrade and others used pomace from the production of isotonic drink for the production of edible packaging materials, including oranges, passion fruit, watermelon, lettuce, zucchini, carrots, spinach, mint, taro, cucumber, and rocket. Polypeptides and polysaccharides are naturally present in many fruit and vegetables, there are several reports on films made exclusively of fruit purées, including peach, apricot, pear, apple, mango, and banana.…”

“…However, edible packaging materials exclusively containing purees often have poor consistency, mechanical strength, and barrier properties, so edible hydrocolloids are added as a binder to improve the physical properties of edible packaging materials. In some cases, the membranes themselves form layers that can not be separated from the surface, which is very important to increase the cohesion of packaging materials …”

“…The authors, while discussing the obtained results, focus mainly on the influence of these additives, some of them also consider the effect of particular components of fruits and vegetables. The proximate compositions were presented only for banana flour, fruit and vegetables residue flour, carrot puree, and ground cranberry pomace and pomace extract . Reis and others considered mango pulp as antioxidant additive added.…”

“…McHugh et al, 41 González-Herrera et al, 39 McHugh and Senesi, 41 Valenzuela and Aguilera, 42,62 Torres et al, 50 Demarchi et al, 51 Du et al, 76,78,59 Ravishankar et al, 79 22 Pelissari et al, 54 Orsuwan and Sothornvit, 55 44 Fai et al, 83 and Ferreira et al 95 Pomace (convective dried powdered solid residue generated by the processing of whole vegetables during juice production) Film, film packaging, coating Cerqueira et al, 13 Azeredo et al, 31 Reis et al, 92 There have appeared novel names for edible packaging materials.…”