Hydrophobic edible films made up of tomato cutin and pectin

Pectin extracted from red dragon fruit (Hylocereus polyrhizus) peel and its usage in edible film

Pectin was extracted from red dragon fruit (Hylocereus polyrhizus) peel using two different extraction methods: subcritical water extraction (SCWE) and conventional acid extraction (AE), from two different types of peels, fresh peel puree and dried peel powder. SCWE method on fresh peel puree showed an ∼18.88 % increase in pectin yield compared to AE. Extracted pectin is classified as low methoxyl pectin (DE: 8.51-50.64 %), with an average molecular weight ranging from 115.23 kDa to 577.84 kDa and a Gal-A content of 44.09 % - 53.90 %. The potential of pectin from fresh peel puree to be applied as a biodegradable film was further explored. Different pectin concentrations (3-5 % w/v) were used to prepare the films. Regarding the film performance, PF-S5, which was produced from SCWE with 5 % of pectin concentration, exhibits better thermal stability (Tdmax 250 °C, residue of 28.69 %) and higher moisture barrier (WVP 5.59 × 10-11 g.cm-1.s-1.Pa-1). In comparison, PF-A showed lower water solubility (45.14-69.15 %), higher water contact angle (33.01° - 44.35°), and better mechanical properties (TS: 2.12-4.11 MPa, EB: 48.72-61.39 %). Higher molecular weight accompanied by higher DE and Gal-A content contributes to better pectin film properties.

Enhancing Cutin Extraction Efficiency from Industrially Derived Tomato Processing Residues by High-Pressure Homogenization

This study primarily aimed to enhance the extraction of cutin from industrial tomato peel residues. Initially, the conventional extraction process was optimized using response surface methodology (RSM). Subsequently, high-pressure homogenization (HPH) was introduced to improve extraction efficiency and sustainability. The optimization process focused on determining the optimal conditions for conventional extraction via chemical hydrolysis, including temperature (100-130 °C), time (15-120 min), and NaOH concentration (1-3%). The optimized conditions, determined as 130 °C, 120 min, and 3% NaOH solution, yielded a maximum cutin extraction of 32.5%. Furthermore, the results indicated that applying HPH pre-treatment to tomato peels before alkaline hydrolysis significantly increased the cutin extraction yield, reaching 46.1%. This represents an approximately 42% increase compared to the conventional process. Importantly, HPH pre-treatment enabled cutin extraction under milder conditions using a 2% NaOH solution, reducing NaOH usage by 33%, while still achieving a substantial cutin yield of 45.6%. FT-IR analysis confirmed that cutin obtained via both conventional and HPH-assisted extraction exhibited similar chemical structures, indicating that the main chemical groups and structure of cutin remained unaltered by HPH treatment. Furthermore, cutin extracts from both conventional and HPH-assisted extraction demonstrated thermal stability up to approximately 200 °C, with less than 5% weight loss according to TGA analysis. These findings underscore the potential of HPH technology to significantly enhance cutin extraction yield from tomato peel residues while utilizing milder chemical hydrolysis conditions, thereby promoting a more sustainable and efficient cutin extraction process.

Innovative Biobased and Sustainable Polymer Packaging Solutions for Extending Bread Shelf Life: A Review

Sustainable packaging has been steadily gaining prominence within the food industry, with biobased materials emerging as a promising substitute for conventional petroleum-derived plastics. This review is dedicated to the examination of innovative biobased materials in the context of bread packaging. It aims to furnish a comprehensive survey of recent discoveries, fundamental properties, and potential applications. Commencing with an examination of the challenges posed by various bread types and the imperative of extending shelf life, the review underscores the beneficial role of biopolymers as internal coatings or external layers in preserving product freshness while upholding structural integrity. Furthermore, the introduction of biocomposites, resulting from the amalgamation of biopolymers with active biomolecules, fortifies barrier properties, thus shielding bread from moisture, oxygen, and external influences. The review also addresses the associated challenges and opportunities in utilizing biobased materials for bread packaging, accentuating the ongoing requirement for research and innovation to create advanced materials that ensure product integrity while diminishing the environmental footprint.

Unveiling the Hidden Properties of Tomato Peels: Cutin Ester Derivatives as Bio-Based Plasticizers for Polylactic Acid

Polylactic acid (PLA) is one of the most important biopolymers employed on the market due to its good mechanical strength and barrier properties. On the other hand, this material presents a rather low flexibility, limiting its employment. The valorization of bio-based agro-food waste for the modification of bioplastics is a highly appealing approach for the replacement of petrol-based materials. The aim of this work is to employ cutin fatty acids derived from a biopolymer (i.e., cutin), present in waste tomato peels and its bio-based derivatives as new plasticizers to enhance PLA flexibility. In particular, pure 10,16-dihydroxy hexadecanoic acid was extracted and isolated from tomato peels and then functionalized to give the desired compounds. All the molecules developed in this study were characterized by NMR and ESI-MS. Blends at different concentrations (10, 20, 30, and 40% w/w) the flexibility (T_g measurements with differential scanning calorimetry-DSC) of the final material. Furthermore, the physical behavior of two blends obtained by mechanical mixing of PLA and 16-methoxy,16-oxohexadecane-1,7-diyl diacetate was investigated through thermal and tensile tests. The data collected by DSC show a lowering in the T_g of all the blends of PLA with functionalized fatty acids, in comparison with pure PLA. Lastly, the tensile tests highlighted how PLA blended with 16-methoxy,16-oxohexadecane-1,7-diyl diacetate (20% w/w) can efficiently enhance its flexibility.

Recent trends in nanocomposite packaging films utilising waste generated biopolymers: Industrial symbiosis and its implication in sustainability

Uncontrolled waste generation and management difficulties are causing chaos in the ecosystem. Although it is vital to ease environmental pressures, right now there is no such practical strategy available for the treatment or utilisation of waste material. Because the Earth's resources are limited, a long-term, sustainable, and sensible solution is necessary. Currently waste material has drawn a lot of attention as a renewable resource. Utilisation of residual biomass leftovers appears as a green and sustainable approach to lessen the waste burden on Earth while meeting the demand for bio-based goods. Several biopolymers are available from renewable waste sources that have the potential to be used in a variety of industries for a wide range of applications. Natural and synthetic biopolymers have significant advantages over petroleum-based polymers in terms of cost-effectiveness, environmental friendliness, and user-friendliness. Using waste as a raw material through industrial symbiosis should be taken into account as one of the strategies to achieve more economic and environmental value through inter-firm collaboration on the path to a near-zero waste society. This review extensively explores the different biopolymers which can be extracted from several waste material sources and that further have potential applications in food packaging industries to enhance the shelf life of perishables. This review-based study also provides key insights into the different strategies and techniques that have been developed recently to extract biopolymers from different waste byproducts and their feasibility in practical applications for the food packaging business.

Recovery and Purification of Cutin from Tomato By-Products for Application in Hydrophobic Films

Tomato pomace is a low-cost, renewable resource that has been studied for the extraction of the biopolyester cutin, which is mainly composed of long-chain hydroxy fatty acids. These are excellent building blocks to produce new hydrophobic biopolymers. In this work, the monomers of cutin were extracted and isolated from tomato pomace and utilized to produce cutin-based films. Several strategies for the depolymerization and isolation of monomeric cutin were explored. Strategies differed in the state of the raw material at the beginning of the extraction process, the existence of a tomato peel dewaxing step, the type of solvent used, the type of alkaline hydrolysis, and the isolation method of cutin monomers. These strategies enabled the production of extracts enriched in fatty acids (16-hydroxyhexadecanoic, hexadecanedioic, stearic, and linoleic, among others). Cutin and chitosan-based films were successfully cast from cutin extracts and commercial chitosan. Films were characterized regarding their thickness (0.103 ± 0.004 mm and 0.106 ± 0.005 mm), color, surface morphology, water contact angle (93.37 ± 0.31° and 95.15 ± 0.53°), and water vapor permeability ((3.84 ± 0.39) × 10^-11 mol·m/m²·s·Pa and (4.91 ± 1.33) × 10^-11 mol·m/m²·s·Pa). Cutin and chitosan-based films showed great potential to be used in food packaging and provide an application for tomato processing waste.

A Comprehensive Overview of Tomato Processing By-Product Valorization by Conventional Methods versus Emerging Technologies

The tomato processing industry can be considered one of the most widespread food manufacturing industries all over the world, annually generating considerable quantities of residue and determining disposal issues associated not only with the wasting of invaluable resources but also with the rise of significant environmental burdens. In this regard, previous studies have widely ascertained that tomato by-products are still rich in valuable compounds, which, once recovered, could be utilized in different industrial sectors. Currently, conventional solvent extraction is the most widely used method for the recovery of these compounds from tomato pomace. Nevertheless, several well-known drawbacks derive from this process, including the use of large quantities of solvents and the difficulties of utilizing the residual biomass. To overcome these limitations, the recent advances in extraction techniques, including the modification of the process configuration and the use of complementary novel methods to modify or destroy vegetable cells, have greatly and effectively influenced the recovery of different compounds from plant matrices. This review contributes a comprehensive overview on the valorization of tomato processing by-products with a specific focus on the use of "green technologies", including high-pressure homogenization (HPH), pulsed electric fields (PEF), supercritical fluid (SFE-CO₂), ultrasounds (UAE), and microwaves (MAE), suitable to enhancing the extractability of target compounds while reducing the solvent requirement and shortening the extraction time. The effects of conventional processes and the application of green technologies are critically analyzed, and their effectiveness on the recovery of lycopene, polyphenols, cutin, pectin, oil, and proteins from tomato residues is discussed, focusing on their strengths, drawbacks, and critical factors that contribute to maximizing the extraction yields of the target compounds. Moreover, to follow the "near zero discharge concept", the utilization of a cascade approach to recover different valuable compounds and the exploitation of the residual biomass for biogas generation are also pointed out.

Pectin-based color indicator films incorporated with spray-dried Hibiscus extract microparticles

Colorimetric films incorporated with anthocyanins as an indicator for freshness monitoring have aroused growing interest recently. The pH-sensing colorimetric film were developed based on pectin (HM), containing aqueous hibiscus extract microparticles (HAE). HAE microparticles were obtained by spray drying with different wall materials (Inulin -IN, maltodextrin- MD and their combination). The films were obtained on large scale by continuous casting. These films were characterized for physicochemical analysis, morphological structure, thermal and barrier properties, antioxidant activity, and color change at different pH. The addition of HAE microparticles caused relevant changes to HM-based films, such as in mechanical behavior and improved barrier property (11-22% WVTR reduction) depending on the type of wall material used and the concentration added. It was verified with the thermal stability of films, with a slight increase being observed. The color variation of smart films was entirely pH-dependent. Overall, the proposed color indicator films showed unique features and functionalities and could be used as an alternative natural pH indicator in smart packaging systems.

A Facile Strategy for Development of pH-Sensing Indicator Films Based on Red Cabbage Puree and Polyvinyl Alcohol for Monitoring Fish Freshness

This study aimed to develop a novel pH-sensing biopolymer film based on red cabbage puree (RCP) incorporated with polyvinyl alcohol (PVA), which was utilized for monitoring fish freshness during storage at 25 °C. A homogenized RCP suspension with a mean particle size of 12.86 ± 0.03 μm and a total anthocyanin concentration of 292.17 ± 2.65 mg/L was directly used as a film-forming substance and anthocyanin source to blend with PVA, showing visual changes in color and ultraviolet-visible spectra within a pH of 2–12. Rheological and microstructural studies certified the strong interactions and good compatibility between the RCP and PVA, resulting in better mechanical properties and water resistance of the composite film than those of a pure RCP film, but without affecting its pH sensitivity. When used for fish freshness monitoring at 25 °C, the developed RCP/PVA film presented visible color differences from purple to yellow, which corresponded to the spoilage threshold of the total volatile basic nitrogen and the total viable count in fish samples. The study highlights that anthocyanin-rich purees of fruits and vegetables, in this case red cabbage puree, can be fully utilized to develop eco-friendly pH-sensing indicator films for intelligent food packaging.

Active food packaging films from alginate and date palm pit extract: Physicochemical properties, antioxidant capacity, and stability

Date palm pits are highly available and inexpensive palm date by-products, representing a valuable source of natural antioxidants, particularly phenolic compounds. Date palm pit extract (DPPE) was prepared from these waste products and characterized for its phenolic content and in vitro antioxidant activity. Profiling DPPE by liquid chromatography coupled with mass spectrometry (LC/MS) showed the presence of dimers and trimers of (epi)catechin as the main constituents. Alginate-based films with four increasing concentrations of DPPE (10%, 20%, 30%, and 40% w/w) were prepared by the casting method. DPPE incorporation reduced solubility values of alginate films by 37%-64% and their surface wettability by 72%-111%. The incorporation of 10% DPPE improved water vapor barrier properties and increased tensile strength (TS) and elongation at break (%E) of alginate films by more than 23%, 50%, and 45%, respectively. The film containing 40% DPPE showed the lowest loss of phenolic content (32%), DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (38%), and ferric reducing antioxidant power (FRAP) (30%) after storage for 3 months.

Valorization of Agro-Industrial Wastes by Ultrasound-Assisted Extraction as a Source of Proteins, Antioxidants and Cutin: A Cascade Approach

The use of agro-industrial wastes to obtain compounds with a high added-value is increasing in the last few years in accordance with the circular economy concept. In this work, a cascade extraction approach was developed based on ultrasound-assisted extraction (UAE) for tomato, watermelon, and apple peel wastes. The protein and antioxidant compounds were obtained during the first extraction step (NaOH 3 wt.%, 98.6 W, 100% amplitude, 6.48 W/cm², 6 min). The watermelon peels (WP) showed higher proteins and total phenolic contents (857 ± 1 mg BSA/g extract and 107.2 ± 0.2 mg GAE/100 g dm, respectively), whereas the highest antioxidant activity was obtained for apple peels (1559 ± 20 µmol TE/100 g dm, 1767 ± 5 µmol TE/100 g dm, and 902 ± 16 µmol TE/100 g dm for ABTS, FRAP and DPPH assays, respectively). The remaining residue obtained from the first extraction was subsequently extracted to obtain cutin (ethanol 40 wt.%, 58 W, 100% amplitude, 2 W/cm², 17 min, 1/80 g/mL, pH 2.5). The morphological studies confirmed the great efficiency of UAE in damaging the vegetal cell walls. WP showed a higher non-hydrolysable cutin content (55 wt.% of the initial cutin). A different monomers’ profile was obtained for the cutin composition by GC-MS, with the cutin from tomato and apple peels being rich in polyhydroxy fatty acids whereas the cutin extracted from WP was mainly based on unsaturated fatty acids. All of the cutin samples showed an initial degradation temperature higher than 200 °C, presenting an excellent thermal stability. The strategy followed in this work has proved to be an effective valorization methodology with a high scaling-up potential for applications in the food, pharmaceutical, nutraceutical, cosmetics and biopolymer sectors.

Argan (Argania spinosa L.) Seed Oil Cake as a Potential Source of Protein-Based Film Matrix for Pharmaco-Cosmetic Applications

Various different agri-food biomasses might be turned into renewable sources for producing biodegradable and edible plastics, potentially attractive for food, agricultural and cosmeceutical sectors. In this regard, different seeds utilized for edible and non-edible oil extraction give rise to high amounts of organic by-products, known as seed oil cakes (SOCs), potentially able to become protein-rich resources useful for the manufacturing of biodegradable films. This study reports the potential of SOC derived from Argania spinosa (argan), a well-known plant containing valuable non-refined oil suitable for food or cosmetic use, to be a promising valuable source for production of a protein-based matrix of biomaterials to be used in the pharmaco-cosmetic sector. Thus, glycerol-plasticized films were prepared by casting and drying using different amounts of argan seed protein concentrate, in the presence of increasing glycerol concentrations, and characterized for their morphological, mechanical, barrier, and hydrophilicity properties. In addition, their antioxidant activity and effects on cell viability and wound healing were investigated. The hydrophobic nature of the argan protein-based films, and their satisfying physicochemical and biological properties, suggest a biorefinery approach for the recycling of argan SOC as valuable raw material for manufacturing new products to be used in the cosmeceutical and food industries.

Functional bioplastics from food residual: Potentiality and safety issues

Plastic pollution and food waste are two global issues with much in common. Plastic containers were introduced as a practical and easy remedy to improve food preservation and reduce the risk of creating waste, but ironically, to address one problem, another has been made worse. The spread of single-use containers has dramatically increased the amount of plastic that has to be discarded, and the most urgent task is now to find a solution to what has become part of the problem. An innovative way around it consists of promoting the valorization of food residues by turning them into novel materials for packaging. Although the results are promising, the aim of completely replacing plastics with biodegradable materials still seems far from being achieved. This review illustrates the main strategies adopted thus far to produce new bioplastic materials and composites from waste resources and focuses on the pros and cons of the food recovery process to look for the aspects that represent an obstacle to the development of the circular food economy on an industrial scale.

Regulating the Physicochemical Properties of Chitosan Films through Concentration and Neutralization

Chitosan offers real potential for use in food preservation, biomedicine, and environmental applications due to its excellent functional properties, such as ease in the fabrication of large films, biocompatibility, and antibacterial properties. However, the production and application of chitosan films were limited by their strong residual acetic acid taste, weak mechanical properties, and poor water vapor barrier properties. In this study, the effects of the chitosan concentration in the film-forming solutions and the neutralization treatment on the physicochemical properties of chitosan films were examined. The results demonstrated that the chitosan concentration affected the mechanical and barrier properties of chitosan films without the neutralization treatment. This was mainly due to the low acetic acid contents in chitosan films after drying. Acetic acid acted as a plasticizer within chitosan films resulting in a looser network structure. After neutralization, the chitosan films showed improvements in properties, with little effect on the chitosan concentration in the film-forming solutions. Moreover, chitosan films after neutralization showed no residual acetic acid. Therefore, neutralization could effectively improve the performance of chitosan films.

Effect of PVOH/PLA + Wax Coatings on Physical and Functional Properties of Biodegradable Food Packaging Films

Biodegradable polymers suffer from inherent performance limitations that severely limit their practical application. Their functionalization by coating technology is a promising strategy to significantly improve their physical properties for food packaging. In this study, we investigated the double coating technique to produce multifunctional, high barrier and heat-sealable biodegradable films. The systems consisted of a web layer, made of poly(lactide) (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT), which was first coated with a poly(vinyl) alcohol based layer, providing high barrier, and then with a second layer of PLA + ethylene-bis-stereamide (EBS) wax (from 0 to 20%), to provide sealability and improve moisture resistance. The films were fully characterized in terms of chemical, thermal, morphological, surface and functional properties. The deposition of the PVOH coating alone, with a thickness of 5 μm, led to a decrease in the oxygen transmission rate from 2200 cm³/m² d bar, for the neat substrate (thickness of 22 μm), to 8.14 cm³/m² d bar (thickness of 27 μm). The deposition of the second PLA layer did not affect the barrier properties but provided heat sealability, with a maximum bonding strength equal to 6.53 N/25 mm. The EBS wax incorporation into the PLA slightly increased the surface hydrophobicity, since the water contact angle passed from 65.4°, for the neat polylactide layer, to 71° for the 20% wax concentration. With respect to the substrate, the double-coated films exhibited increased stiffness, with an elastic modulus ca. three times higher, and a reduced elongation at break, which, however still remained above 75%. Overall, the developed double-coated films exhibited performances comparable to those of the most common synthetic polymer films used in the packaging industry, underlining their suitability for the packaging of sensitive foods with high O₂-barrier requirements.

Trafficking Processes and Secretion Pathways Underlying the Formation of Plant Cuticles

Cuticles are specialized cell wall structures that form at the surface of terrestrial plant organs. They are largely comprised lipidic compounds and are deposited in the apoplast, external to the polysaccharide-rich primary wall, creating a barrier to diffusion of water and solutes, as well as to environmental factors. The predominant cuticle component is cutin, a polyester that is assembled as a complex matrix, within and on the surface of which aliphatic and aromatic wax molecules accumulate, further modifying its properties. To reach the point of cuticle assembly the different acyl lipid-containing components are first exported from the cell across the plasma membrane and then traffic across the polysaccharide wall. The export of cutin precursors and waxes from the cell is known to involve plasma membrane-localized ATP-binding cassette (ABC) transporters; however, other secretion mechanisms may also contribute. Indeed, extracellular vesiculo-tubular structures have recently been reported in Arabidopsis thaliana (Arabidopsis) to be associated with the deposition of suberin, a polyester that is structurally closely related to cutin. Intriguingly, similar membranous structures have been observed in leaves and petals of Arabidopsis, although in lower numbers, but no close association with cutin formation has been identified. The possibility of multiple export mechanisms for cuticular components acting in parallel will be discussed, together with proposals for how cuticle precursors may traverse the polysaccharide cell wall before their assimilation into the cuticle macromolecular architecture.

Functional property optimization of sodium caseinate-based films incorporating functional compounds from date seed co-products using response surface methodology

Novel sodium caseinate films incorporating furfural and date seed oil (DSO) were produced. The effects of furfural and DSO contents on the functional and physical properties of the composite films were assessed using response surface methodology.

From mango by-product to food packaging: Pectin-phenolic antioxidant films from mango peels

The objective of the study was to prepare active films based on pectin and polyphenol-rich extracts from Tommy Atkins mango peels. Aqueous and methanolic extracts showed a variety of phenolic compounds that were identified by UPLC-MS analysis, and a high content of total phenolics that were quantified by the Folin-Ciocalteau method. The methanolic extract showed better results in antioxidant tests and was more effective in inhibiting the growth of Gram-positive and Gram-negative bacteria. The pectin extracted from mango peels showed good thermal stability and a degree of methoxylation of 58.3% by ¹H NMR. The films containing the phenolic extracts showed lower water vapor permeability when compared to the control film (without any phenolic extracts). The incorporation of the extracts led to an increase in elongation (ε) and a decrease in tensile strength (σ) and modulus of elasticity (Y). The films with aqueous or methanolic extracts showed higher antioxidant activity in terms of inhibition of the DPPH radical. Therefore, the films developed in this work are presented as a promising alternative for food packaging and/or coating applications.

Liquid and Solid Functional Bio-Based Coatings

The development of new bio-based coating materials to be applied on cellulosic and plastic based substrates, with improved performances compared to currently available products and at the same time with improved sustainable end of life options, is a challenge of our times. Enabling cellulose or bioplastics with proper functional coatings, based on biopolymer and functional materials deriving from agro-food waste streams, will improve their performance, allowing them to effectively replace fossil products in the personal care, tableware and food packaging sectors. To achieve these challenging objectives some molecules can be used in wet or solid coating formulations, e.g., cutin as a hydrophobic water- and grease-repellent coating, polysaccharides such as chitosan-chitin as an antimicrobial coating, and proteins as a gas barrier. This review collects the available knowledge on functional coatings with a focus on the raw materials used and methods of dispersion/application. It considers, in addition, the correlation with the desired final properties of the applied coatings, thus discussing their potential.

Disposable Food Packaging and Serving Materials-Trends and Biodegradability

Food is an integral part of everyone’s life. Disposable food serving utensils and tableware are a very convenient solution, especially when the possibility of the use of traditional dishes and cutlery is limited (e.g., takeaway meals). As a result, a whole range of products is available on the market: plates, trays, spoons, forks, knives, cups, straws, and more. Both the form of the product (adapted to the distribution and sales system) as well as its ecological aspect (biodegradability and life cycle) should be of interest to producers and consumers, especially considering the clearly growing trend of “eco-awareness”. This is particularly important in the case of single-use products. The aim of the study was to present the current trends regarding disposable utensils intended for contact with food in the context of their biodegradability. This paper has summarized not only conventional polymers but also their modern alternatives gaining the attention of manufacturers and consumers of single-use products (SUPs).

Use of Industrial Wastes as Sustainable Nutrient Sources for Bacterial Cellulose (BC) Production: Mechanism, Advances, and Future Perspectives

A novel nanomaterial, bacterial cellulose (BC), has become noteworthy recently due to its better physicochemical properties and biodegradability, which are desirable for various applications. Since cost is a significant limitation in the production of cellulose, current efforts are focused on the use of industrial waste as a cost-effective substrate for the synthesis of BC or microbial cellulose. The utilization of industrial wastes and byproduct streams as fermentation media could improve the cost-competitiveness of BC production. This paper examines the feasibility of using typical wastes generated by industry sectors as sources of nutrients (carbon and nitrogen) for the commercial-scale production of BC. Numerous preliminary findings in the literature data have revealed the potential to yield a high concentration of BC from various industrial wastes. These findings indicated the need to optimize culture conditions, aiming for improved large-scale production of BC from waste streams.

Potentials of polysaccharides, lipids and proteins in biodegradable food packaging applications

Bio-based packaging materials are gaining importance due to their biodegradability, sustainability and environmental friendliness. To control the food quality and improve the food safety standards, proteins polysaccharide and lipid-based packaging films are enriched with bioactive and functional substances. However, poor permeability and mechanical characteristics are the challenging areas in their commercialization. Scientists and researchers are using a combination of techniques i.e. hydrogels, crosslinking, etc. to improve the intermolecular forces between different components of the film formulation to counter these challenges More recently, biodegradable packaging materials, sometimes edible, are also used for the delivery of functional ingredients which reveals their potential for drug delivery to counter the nutrient deficiency problems. This study highlights the potentials of bio-based materials i.e. proteins, polysaccharides, lipids, etc. to develop biodegradable packaging materials. It also explores the additives used to improve the physicochemical and mechanical properties of biodegradable packaging materials. Furthermore, it highlights the novel trends in biodegradable packaging from a food safety and quality point of view.

Development of quaternary nanocomposites made up of cassava starch, cocoa butter, lemongrass essential oil nanoemulsion, and brewery spent grain fibers

We report on production of novel quaternary nanocomposite films based on thermoplastic starch (TPS, 8% w/v) derived from cassava, cocoa butter, (CB, 30% wt.%), and lemongrass essential oil (LEO, 1:1) nanoemulsions reinforced with different concentrations of brewery spent grain (BSG, 5 or 10 wt.%) fibers, by continuous casting. The chemical composition, the morphological, thermal, mechanical properties, film barrier, biodegradability in the vegetable compound, in addition to the application in chocolates, have been widely studied. The addition of CB, LEO, and BSG caused relevant changes in the starch-based films, such as increased extensibility (from 2.4-BSG5 to 9.4%-BSG10) and improved barrier to moisture (2.9 and 2.4 g.mm.kPa^-1 .h^-1 .m^-2 ). Contrastingly, the thermal stability of the starch film was slightly decreased. The biodegradability of the herein developed quaternary nanocomposite films was the same as that of TPS films, eliminating concerns on the supplementation with active ingredients that are expected to have some biocidal effect. Despite checking antimicrobial activity only by contact under the biocomposites, chocolates packed with the films were well accepted by consumers, especially the samples of white chocolate stored in the BSG5 biocomposite. Overall, this new approach towards quaternary active, biodegradable films produced in a pilot-scale lamination unit was successful in either improving or at least maintaining the essential properties of TPS-based films for food packaging applications, while providing them with unique features and functionalities. PRACTICAL APPLICATION: This contribution relates to new approach toward quaternary films produced in a pilot-scale lamination unit. It relates to sustainability as it is both biodegradable and based on plant biomass, as well as produced via a clean, through high-yield process. The four components of the edible films we developed provide it with good in properties performance, as both a passive barrier (i.e. purely physical), and active, related to the sensory attributes of food, essential to be applied in food packaging. The valorization of a BSG also adds to the relevance of our contribution within the circular bioeconomy framework.

Fabrication and Characterization of Chitosan/Cellulose Nanocrystal/Glycerol Bio-Composite Films

Cellulose nanocrystal (CNC)-reinforced bio-composite films containing glycerol were produced using the solution casting technique. The influences of the addition of CNC (2, 4, and 8 wt%) and glycerol (10, 20, and 30 wt%) on the properties of the bio-composite films were studied in the present work. The resulting films were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetry analysis (TGA), and according to their tensile, water absorption, and light transmission behavior. The introduction of 4 wt% CNC into the chitosan film did not affect the thermal stability, but the presence of 20 wt% glycerol reduced the thermal stability. The addition of 4 wt% CNC to the chitosan film increased its tensile strength, tensile modulus, and elongation at break by 206%, 138%, and 277%, respectively. However, adding more than 8 wt% CNC resulted in a drastic reduction in the strength and ductility of the chitosan film. The highest strength and stiffness of the chitosan bio-composite film were attained with 4 wt% CNC and 20 wt% glycerol. The water absorption and light transmission of the chitosan film were reduced dramatically by the presence of both CNC and glycerol.

Pectin/pullulan blend films for food packaging: Effect of blending ratio

Edible films were prepared using various pectin and pullulan mixing ratios and evaluated for their properties in food packaging applications. FTIR characterization showed that an intermolecular H-bond was formed between the hydroxyl group of pullulan and the carboxyl group of pectin. As observed by FE-SEM, as the pullulan content increased, the film's surface became smoother and formed a film with a denser structure, leading to an increased water vapor barrier. The blend film with a 50:50 ratio of pullulan and pectin exhibited the highest thermal stability and surface hydrophobicity. Blending also increased strength while maintaining flexibility and stiffness compared to the individual films. Besides, the films with ratios above 50:50 displayed the least water and oil absorption values.

Fabrication of hydrophobic and high-strength packaging films based on the esterification modification of galactomannan

There is an increasing interest in substituting current packaging films with biologically-derived films without compromising mechanical properties and hydrophobicity. In this work, the esterified galactomannan (E-GM) films with good hydrophobicity, excellent oxygen barrier performance and high tensile mechanical strength were synthesized using anhydride esterification method prior to film formation. The hydrophobicity, mechanical properties, barrier properties, thermal stability and ultraviolet absorption of the prepared films were determined to fully investigate the features of galactomannan-based films. The results indicated that GM films can be successfully obtained by esterification. Compared to neat GM film, E-GM-1.5 film (acetic anhydride to GM of 1.5:1) achieved the highest degree of esterification (0.05), hydrophobicity (107°) and mechanical strength (92.0 MPa). In addition, the esterified GM films had lower toxicity for macrophages cells. The prepared E-GM films may provide more opportunities for further advancement and applications in the development of food packaging from natural resources.

Elucidating esterification reaction during deposition of cutin monomers from classical molecular dynamics simulations

The structural behavior of some cutin monomers, when deposited on mica support, was extensively investigated by our research group. However, other events, such as esterification reaction (ER), are still a way to explore. In this paper, we explore possible ER that could occur when these monomers adsorb on support. Although classical molecular dynamics simulations are not able to capture reactive effects, here, we show that they become valuable strategies to analyze the initial structural configurations to predict the most favorable reaction routes. Thus, when depositing aleuritic acid (ALE), it is observed that the loss of capacity to form self-assembled (SA) systems favors different routes to occur ER. In pure ALE bilayers systems, an ER is given exclusively through the -COOH and primary -OH groups. In pure ALE monolayers systems, the ER does not happen when the system is self-assembled. However, for disorganized systems, it is able to occur by two possible routes: -COOH and primary -OH (route 1) and -COOH and secondary -OH (route 2). When palmitic acid (PAL) is added in small quantities, ALE SAMs can now form an ER. In this case, ER occurs mostly through the -COOH and secondary -OH groups. However, when the presence of PAL is dominant, ER can occur with either of both possibilities, that is, routes 1 and 2. Graphical abstract.

Tuning the physicochemical properties of apple pectin films by incorporating chitosan/pectin fiber

Various biodegradable or edible films were designed to deal with the environmental threats from plastic films. To overcome the defects of pectin film, the feasibility for the incorporation of CH/PE fiber was explored. Micron-scale novel artificial CH/PE fibers in needle, spindle or whisker shape with a diameter around 25 μm were fabricated via a shearing regime in virtue of electrostatic complexing. The incorporation of CH/PE fiber (mixture) and its size-fractioned portions (small and large) substantially changed PE films in diverse ways. Structurally, the fiber-incorporated films were heterogeneous with the fibers concentrated in the upper layer, although they presented similar FT-IR spectra and XRD pattern to PE film. Regarding the film performance, the incorporation of CH/PE fibers, especially the small portion, rendered the PE film with higher values in water-proof ability, thermal stability, break resistibility, stretchability and UV blocking capacity. More importantly, this work provided an innovative strategy to improve the performance of edible films.

Fruits and vegetable-processing waste: a case study in two markets at Rio de Janeiro, RJ, Brazil

Fruits and vegetables (FV) consumed in natura or processed produce a significant volume of waste, causing an economic deficit in the productive chain. FV markets feature a significant production of vegetable residues with potential of use, since they commercialize an increasing amount of minimally processed vegetables and fruit juices. To this end, it is important to identify, quantify, and characterize these wastes and to propose feasible and coherent alternatives for their use at regional and worldwide levels. In this paper, a case study of two FV markets in Rio de Janeiro, Brazil, was conducted to identify and quantify FV processing waste. Over a period of 20 days, the FV residues from 31 vegetables and 17 fruits were identified and weighed. It is estimated by extrapolation that 106,000 kg of FV were processed in 1 year in two units of FV markets and 48.6% of FV were discarded as by-products. This may be a consequence of factors that contribute to waste generation, such as the low preparation and/or training of the manipulators as well as the quality of the equipment and the maintenance thereof. Thus, studies that aim to understand the environmental impact by monitoring the of FV waste are fundamental, since this waste can be used as raw material and converted into value-added products.

Recent Trends in the Use of Pectin from Agro-Waste Residues as a Natural-Based Biopolymer for Food Packaging Applications

Regardless of the considerable progress in properties and versatility of synthetic polymers, their low biodegradability and lack of environmentally-friendly character remains a critical issue. Pectin is a natural-based polysaccharide contained in the cell walls of many plants allowing their growth and cell extension. This biopolymer can be extracted from plants and isolated as a bioplastic material with different applications, including food packaging. This review aims to present the latest research results regarding pectin, including the structure, different types, natural sources and potential use in several sectors, particularly in food packaging materials. Many researchers are currently working on a multitude of food and beverage industry applications related to pectin as well as combinations with other biopolymers to improve some key properties, such as antioxidant/antimicrobial performance and flexibility to obtain films. All these advances are covered in this review.

Production of cutinase from Fusarium falciforme and its application for hydrophilicity improvement of polyethylene terephthalate fabric

Among 23 isolates of cutinase-producing fungi from Thailand, one strain of Fusarium falciforme PBURU-T5 exhibited the greatest cutinase activity (3.36 ± 0.12 U ml^-1) against p-nitrophenyl butyrate. This strain was found to produce an inducible cutinase when cultivated in the liquid mineral medium containing cutin from papaya peel as the sole carbon source. By optimizing the production condition based on the central composite experimental design, the maximal cutinase activity up to 4.82 ± 0.18 U ml^-1 was attained under the condition: 0.4% (w/v) papaya cutin as the carbon source, 0.3% (w/v) peptone as the nitrogen source, incubation temperature at 30 °C for 4 days, and initial pH 7.0. The crude enzyme was optimally active at 35 °C and pH 9.0 which was suitable for textile industrial application. The treatment with the crude PBURU-T5 cutinase (100 U g^-1 dry weight of fabric) could enhance the wetting time, water adsorption and moisture regain of polyethylene terephthalate fabric up to 1.9-, 1.2- and 1.3-fold, respectively, comparing with the conventional 1M NaOH treatment. The increment of these fabric properties by enzymatic treatment could facilitate the dyeing process and enhance the fabric softness. Thus, F. falciforme PBURU-T5 is the promising source of cutinase for the modification of the PET fabric surface.

Development and characterization of novel composite glycerol-plasticized films based on sodium caseinate and lipid fraction of tomato pomace by-product

Tomato processing industries generate many byproducts that are mainly unexploited or underutilized. In order to convert tomato byproducts into added-value products, composite films made of sodium caseinate (NaCas), glycerol (25 wt%), and lipidic fraction of tomato pomace (LFTP) at different contents (0-40 wt%) were produced and characterized in terms of thermal stability, antioxidant activities, mechanical, hydrodynamic and optical properties. Our results showed that increasing LFTP concentration beyond 20 wt% increased the flexibility of NaCas films within the range of 17-25%. Moreover, LFTP incorporation at the highest content improved thermal stability of NaCas films and reduced their water absorption by >72%. Furthermore, increasing LFTP content led to a significant decrease in the light transmission of NaCas/LFTP composite films. Such improvement in functional and physical properties can be attributed not only to the establishment of specific interactions between NaCas and LFTP but also to their good miscibility in the blend along with the homogeneous dispersion of the incorporated LFTP in the polymeric matrix, as confirmed by FTIR and SEM analysis. On the other hand, the antioxidant capacity of NaCas/LFTP composite films was enhanced by increasing LFTP content most likely due to LFTP's high total phenolics content.

Glycerol-Plasticized Films Obtained from Whey Proteins Denatured at Alkaline pH

Whey represents the major by-product of cheese industry. One possibility to recycle the whey wastes is the use of their globular proteins as a polymer source for the production of biodegradable plastic materials. Whey protein (WP)-based films are usually obtained by protein heat treatment in the presence of glycerol (GLY) as plasticizer at pH 7, a method which would require commercially high costing process. In this work we explored the possibility of producing manageable whey-derived materials without any heat-treatment but under alkaline conditions. The reported results demonstrated that the casting at pH 12 of the unheated WP film forming solutions (FFSs), containing either 40% or 50% GLY, led to produce more resistant and flexible materials than the ones obtained at pH 7. Film opacity was observed significantly increased, being higher in the samples obtained at alkaline pH without WP heating and with higher GLY concentrations. Finally, moisture content decreased with the reduction of GLY content, both in heated and unheated WP-based films, whereas water uptake of the different films prepared at pH 12 did not significantly change.

Effect of Mesoporous Silica Nanoparticles on Glycerol-Plasticized Anionic and Cationic Polysaccharide Edible Films

This study describes the production of reinforced polysaccharide (PS)-based films, by adding mesoporous silica nanoparticles (MSNs), to either pectin (PEC) or chitosan (CH) film forming solutions, either containing glycerol (GLY) as a plasticizer, or not. Film characterization demonstrated that MSNs and GLY were able to significantly increase the plasticity of both PS-based biomaterials and that the interactions between PSs and nanoparticles were mainly due to hydrogen bonds. Moreover, MSN-containing films were less transparent, compared to controls prepared with either PEC or CH, in the absence of GLY, while all films containing MSNs, but obtained with the plasticizer, were as transparent as the films prepared with PEC or CH alone. MSN addition did not influence the thickness of the PEC-based films, but increased that of CH-based ones, prepared both in the absence and presence of GLY. MSN-containing PEC-based films possessed a more compact and homogeneous morphology, with respect to both control films, prepared, with or without GLY, and to the CH-based films, containing MSNs, the structure of which showed numerous agglomerations. Finally, moisture content and uptake were reduced, in all films prepared in the presence of MSNs. The suggested addition of MSNs might have given rise to novel biomaterials for food or pharmaceutical applications.