Hydrophobic edible films made up of tomato cutin and pectin

Valorization of Tomato Processing by-Products: Fatty Acid Extraction and Production of Bio-Based Materials

A method consisting of the alkaline hydrolysis of tomato pomace by-products has been optimized to obtain a mixture of unsaturated and polyhydroxylated fatty acids as well as a non-hydrolysable secondary residue. Reaction rates and the activation energy of the hydrolysis were calculated to reduce costs associated with chemicals and energy consumption. Lipid and non-hydrolysable fractions were chemically (infrared (IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS)) and thermally (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)) characterized. In addition, the fatty acid mixture was used to produce cutin-based polyesters. Freestanding films were prepared by non-catalyzed melt-polycondensation and characterized by Attenuated Total Reflected-Fourier Transform Infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (NMR), DSC, TGA, Water Contact Angles (WCA), and tensile tests. These bio-based polymers were hydrophobic, insoluble, infusible, and thermally stable, their physical properties being tunable by controlling the presence of unsaturated fatty acids and oxygen in the reaction. The participation of an oxidative crosslinking side reaction is proposed to be responsible for such modifications.

Nanofibrillated bacterial cellulose and pectin edible films added with fruit purees

Bacterial cellulose (BC) is a water resistant and strong material for edible films. Previous studies have been conducted on edible films containing fruit purees, but not using BC. In this study, films with or without fruit (mango or guava) purees were prepared using different ratios of nanofibrillated BC (NFBC) to pectin. The addition of fruit purees increased water vapor permeability (in about 13-18 times), reduced tensile strength (in more than 90%) and modulus (in about 99%), and increased elongation (in about 13 times), due to plasticizing effects of fruit sugars and matrix dilution by the purees. The partial or total replacement of pectin with NFBC resulted in improved physical properties, making the films stronger, stiffer, more resistant to water, and with enhanced barrier to water vapor. Fruit containing films based on pectin are suggested for sachets, whereas applications for food wrapping or coating may benefit from the use of NFBC.

Assembly of the Cutin Polyester: From Cells to Extracellular Cell Walls

Cuticular matrices covering aerial plant organs or delimiting compartments in these organs are composed of an insoluble hydrophobic polymer of high molecular mass, i.e., cutin, that encompass some cell wall polysaccharides and is filled by waxes. Cutin is a polyester of hydroxy and-or epoxy fatty acids including a low amount of glycerol. Screening of Arabidopsis and more recently of tomato (Solanum lycopersicum) mutants allowed the delineation of the metabolic pathway involved in the formation of cutin monomers, as well as their translocation in the apoplast. Furthermore, these studies identified an extracellular enzyme involved in the polymerization of these monomers, i.e., cutin synthase 1 (CUS1), an acyl transferase of the GDSL lipase protein family. By comparing the structure of tomato fruit cutins from wild type and down-regulated CUS1 mutants, as well as with the CUS1-catalyzed formation of oligomers in vitro, hypothetical models can be elaborated on the polymerization of cutins. The polymorphism of the GDSL-lipase family raises a number of questions concerning the function of the different isoforms in relation with the formation of a composite material, the cuticle, containing entangled hydrophilic and hydrophobic polymers, i.e., polysaccharides and cutin, and plasticizers, i.e., waxes.

Cutin from agro-waste as a raw material for the production of bioplastics

Cutin is the main component of plant cuticles constituting the framework that supports the rest of the cuticle components. This biopolymer is composed of esterified bi- and trifunctional fatty acids. Despite its ubiquity in terrestrial plants, it has been underutilized as raw material due to its insolubility and lack of melting point. However, in recent years, a few technologies have been developed to obtain cutin monomers from several agro-wastes at an industrial scale. This review is focused on the description of cutin properties, biodegradability, chemical composition, processability, abundance, and the state of art of the fabrication of cutin-based materials in order to evaluate whether this biopolymer can be considered a source for the production of renewable materials.

Scale-Up Preparation and Characterization of Collagen/Sodium Alginate Blend Films

In an effort to produce scale-up of edible films, collagen-based films including different amounts of sodium alginate (CS) were prepared by casting method. Films were characterized based on their rheological, thermal, and mechanical properties, water vapor permeability (WVP), and oxygen permeability (OP). The microstructures were also evaluated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform-infrared spectroscopy (FTIR). Furthermore, the addition of sodium alginate effectively improved the viscosity and thermal stability, significantly increased TS, and decreased E and WVP (P<0.05), but with no obvious effect on OP (P>0.05). SEM and AFM showed homogeneous matrix, with no signs of phase separation in the blends. Overall, films (CS2) produced using collagen (g) : sodium alginate (g) = 10 : 2 showed suitable rheological property (apparent viscosity was 4.87 m Pa s−1) and better TS (26.49 Mpa), E (64.98%), WVP (1.79 × 10−10 g·cm−1·s−1·Pa−1), and OP (3.77 × 10−5 cm3·m−2·d−1·Pa−1).