Cellulose Nanofibers from Olive Tree Pruning as Food Packaging Additive of a Biodegradable Film

Abstract

A biodegradable packaging film containing cellulose nanofibers from olive tree pruning, a by-product of olives production, was obtained using a solvent casting method. Nanocellulose was added to polyvinyl alcohol (PVA) to enhance the technological properties of the composite film as food packaging material. Nanocellulose was obtained from unbleached and bleached pulp through a mechanical and TEMPO pretreatment. Crystalline and chemical structure, surface microstructure, UV and gas barrier, optical, mechanical and antioxidant properties, as well as thermal stability were evaluated. Regarding optical properties, the UV barrier was increased from 6% for the pure PVA film to 50% and 24% for unbleached and bleached nanocellulose, respectively. The antioxidant capacity increased significantly in unbleached mechanical nanocellulose-films (5.3%) compared to pure PVA film (1.7%). In terms of mechanical properties, the tensile strength of the 5% unbleached mechanical nanocellulose films was significantly improved compared to the pure PVA film. Similarly, the 5% nanocellulose films had increased the thermal stability and improved barrier properties, reducing water vapor permeability by 38–59% and presenting an oxygen barrier comparable to aluminum layer and plastic films. Our results support the use of the developed films as a green alternative material for food packaging.

Olive byproducts and their bioactive compounds as a valuable source for food packaging applications

“…Sánchez‐Gutiérrez et al. (2021) found that the incorporation of cellulose nanofibers isolated from olive tree pruning into PVA films enhanced their antioxidant activity, thermal stability, and water vapor, oxygen, and UV‐light barrier properties. The inherent flexibility of cellulose nanofibers and the presence of lignin may contribute to the formation of a more compact and denser film structure, thus, lowering porosity and oxygen transmission rate.…”

“…The inherent flexibility of cellulose nanofibers and the presence of lignin may contribute to the formation of a more compact and denser film structure, thus, lowering porosity and oxygen transmission rate. Sánchez-Gutiérrez et al (2021) reported the potential use of PVA reinforced with cellulose nanofibers as antioxidant packaging for food susceptible to lipid oxidation. The comparison of the different results obtained from several published articles is difficult to perform because the properties of composite films incorporating bioactive compounds from olive byproducts may be affected by many factors, such as structure and chemical composition of the film matrix, type, concentration, origin, properties, and extraction method and parameters of bioactive compounds, film preparation method and conditions, and the interactions between the film constituents and bioactive molecules (Aloui & Khwaldia, 2016;.…”

“…Abdel-Halim et al (2015) converted cellulose extracted from olive tree pruning and having small length fibers and low mechanical strength into water-soluble hydroxypropyl carboxymethyl cellulose through two etherification reactions. Nanocellulose isolated from olive tree pruning using TEMPO-mediated oxidation pretreatment followed by microfluidization formed a strong and transparent viscoelastic gel and exhibited a higher crystallinity index than eucalyptus nanocellulose, making it a novel candidate to reinforce pulp, paper, and packaging films and coatings (Sánchez-Gutiérrez et al, 2021). The reinforcing efficiency of nanocellulose is promoted by its hydrophilic and semicrystalline nature and the presence of lignin, forming a dense network and imparting improved packaging functional properties to polymeric matrices (Fillat et al, 2018).…”

Research Progress of Polyvinyl Alcohol Water-Resistant Film Materials

“…Sánchez-Gutiérrez et al [ 45 ] prepared biodegradable films by incorporating CNF obtained from olive trees into PVA. SEM indicates a uniform distribution of CNF without layer separation; FTIR shows a peak at 3250 cm −1 , which is attributed to the typical O-H stretching vibrations of inter- and intramolecular hydrogen bonds.…”

Lignocellulose Nanofibre Obtained from Agricultural Wastes of Tomato, Pepper and Eggplants Improves the Performance of Films of Polyvinyl Alcohol (PVA) for Food Packaging

“…These CNF could be obtained from plant biomass proceeding from agricultural by-products, making it a highly available and very low-cost resource. The CNFs could be used for the manufacture of food packaging, resulting in value-added materials produced in a sustainable and environmentally friendly way [ 20 ]. In 2020, vegetable production in Spain reached almost 16 million tonnes, with Andalusia being the region with the highest vegetable production (33% of the total) [ 21 ].…”