Biopolymer-Based Sustainable Food Packaging Materials: Challenges, Solutions, and Applications

Influence of a Biofiller, Polylactide, on the General Characteristics of Epoxy-Based Materials

The aim of this work was to obtain epoxy-based composite structures with good mechanical performance, high aging resistance, and an improved degradability profile. For this purpose, powdered polylactide in the amount of 5, 10, 20, 30, and 40 phr was introduced into the epoxy resin, and the composites were fabricated by a simple method, which is similar to that used on an industrial scale in the fabrication of these products. The first analysis concerned the study of the effect of PLA addition to epoxy resin-based composites on their mechanical properties. One-directional tensile tests of samples were performed for three directions (0, 90, and 45 degrees referring to the plate edges). Another aspect of this research was the assessment of the resistance of these composites to long-term exposure to solar radiation and elevated temperature. Based on the obtained results, it was observed that the samples containing 20 or 40 phr of polylactide were characterized by the lowest resistance to the solar aging process. It was therefore concluded that the optimal amount of polylactide in the epoxy resin composite should not be greater than 10 phr to maintain its mechanical behavior and high aging resistance. In the available literature, there are many examples in which scientists have proposed the use of various biofillers (e.g., lignin, starch, rice husk, coconut shell powder) in epoxy composites; however, the impact of polylactide on the general characteristics of the epoxy resin has not been described so far. Therefore, this work perfectly fills the gaps in the literature and may contribute to a more widespread use of additives of natural origin, which may constitute an excellent alternative to commonly used non-renewable compounds.

Nanocomposites and their application in antimicrobial packaging

The advances in nanocomposites incorporating bioactive substances have the potential to transform the food packaging sector. Different nanofillers have been incorporated into polymeric matrixes to develop nanocomposite materials with improved mechanical, thermal, optical and barrier properties. Nanoclays, nanosilica, carbon nanotubes, nanocellulose, and chitosan/chitin nanoparticles have been successfully included into polymeric films, resulting in packaging materials with advanced characteristics. Nanostructured antimicrobial films have promising applications as active packaging in the food industry. Nanocomposite films containing antimicrobial substances such as essential oils, bacteriocins, antimicrobial enzymes, or metallic nanoparticles have been developed. These active nanocomposites are useful packaging materials to enhance food safety. Nanocomposites are promising materials for use in food packaging applications as practical and safe substitutes to the traditional packaging plastics.

Purification, bioactivity and application of maltobionic acid in active films

The objective of this study was to purify sodium maltobionate using Zymomonas mobilis cells immobilized in situ on flexible polyurethane (PU) and convert it into maltobionic acid for further evaluation of bioactivity (iron chelating ability, antibacterial potential and cytoprotection) and incorporation into films based on cassava starch, chitosan, and cellulose acetate. Sodium maltobionate exhibited a purity of 98.1% and demonstrated an iron chelating ability of approximately 50% at concentrations ranging from 15 to 20 mg mL-1. Maltobionic acid displayed minimal inhibitory concentrations (MIC) of 8.5, 10.5, 8.0, and 8.0 mg mL-1 for Salmonella enterica serovar Choleraesuis, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes, respectively. Maltobionic acid did not exhibit cytotoxicity in HEK-293 cells at concentrations up to 500 µg mL-1. Films incorporating 7.5% maltobionic acid into cassava starch and chitosan demonstrated inhibition of microbial growth, with halo sizes ranging from 15.67 to 22.33 mm. These films had a thickness of 0.17 and 0.13 mm, water solubility of 62.68% and 78.85%, and oil solubility of 6.23% and 11.91%, respectively. The cellulose acetate film exhibited a non-uniform visual appearance due to the low solubility of maltobionic acid in acetone. Mechanical and optical properties were enhanced with the addition of maltobionic acid to chitosan and cassava films. The chitosan film with 7.5% maltobionic acid demonstrated higher tensile strength (30.3 MPa) and elongation at break (9.0%). In contrast, the cassava starch film exhibited a high elastic modulus (1.7). Overall, maltobionic acid, with its antibacterial activity, holds promise for applications in active films suitable for food packaging.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03879-3.

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.

Development of smart packaging halochromic films embedded with anthocyanin pigments; recent advances

Nowadays, innovative biodegradable packaging based on pH-sensitive natural dyes is being developed. These smart systems quickly inform the food quality to the consumer and monitor fresh foods in real-time. Smart packaging protects food against ambiance risks and simultaneously sends information to users for variations and alterations in the packaging settings. Anthocyanin (ACY), among the natural dyes used as indicators serves as water-soluble flavonoid pigments which made reflection in light in the red-blue range and can detect chemical and microbial alterations in foods based on their pH-susceptible conditions; on the other hand, they have considerable antimicrobial and antioxidant functions that result in the longer shelf life of food products. They also have beneficial properties including anti-cancer and anti-inflammatory functions, avoidance of heart diseases, overweight, and diabetes. Hence, this paper deals with the characteristics of smart packaging films based on anthocyanins, as well as their application in various food industries.

Evaluation of the use of Idesia polycarpa Maxim protein coating to extend the shelf life of European sweet cherries

Idesia polycarpa Maxim protein was used as a substrate to prepare a novel food packaging material with bioactive functions for encapsulating and extending the postharvest shelf life of sweet cherries. The film-forming solution was prepared from a mixture of Idesia polycarpa Maxim protein, glycerol, and gelatin, and was cast to form a film at room temperature and evaluated for mechanical, optical, structural, crystallinity, thermal properties, morphology, and antioxidant activity. Idesia polycarpa Maxim protein composite film solution was applied as an edible coating on sweet cherries and evaluated for changes in physical and biochemical parameters of sweet cherries in storage at 20°C and 50% relative humidity for 9 days. The results showed that the film tensile strength increased from 0.589 to 1.981 Mpa and the elongation at break increased from 42.555% to 58.386% with the increase of Idesia polycarpa Maxim protein concentration. And in the in vitro antioxidant assay, IPPF-4.0% was found to have the best antioxidant activity, with scavenging rates of 65.11% ± 1.19%, 70.74% ± 0.12%, and 90.96% ± 0.49% for DPPH radicals, ABTS radicals, and hydroxyl radicals, respectively. Idesia polycarpa Maxim protein coating applied to sweet cherries and after storage at 20°C and 50% relative humidity for 9 days, it was found that the Idesia polycarpa Maxim protein coating significantly reduced the weight loss (54.82% and 34.91% in the Control and Coating-2.5% groups, respectively) and the loss of ascorbic acid content (16.47% and 37.14% in the Control and Coating-2.5% groups, respectively) of the sweet cherries, which can effectively extend the aging of sweet cherry fruits and prolong their shelf life. The developed protein film of Idesia polycarpa Maxim with antioxidant activity can be used as a new food packaging material in the food industry.

Fluid Mechanics of Droplet Spreading of Chitosan/PVA-Based Spray Coating Solution on Banana Peels with Different Wettability

The spreading behavior of a coating solution is an important factor in determining the effectiveness of spraying applications. It determines how evenly the droplets spread on the substrate surface and how quickly they form a uniform film. Fluid mechanics principles govern it, including surface tension, viscosity, and the interaction between the liquid and the solid surface. In our previous work, chitosan (CS) film properties were successfully modified by blending with polyvinyl alcohol (PVA). It was shown that the mechanical strength of the composite film was significantly improved compared to the virgin CS. Here we propose to study the spreading behavior of CS/PVA solution on fresh bananas. The events upon droplet impact were captured using a high-speed camera, allowing the identification of outcomes as a function of velocity at different surface wettabilities (wetting and non-wetting) on the banana peels. The mathematical model to predict the maximum spreading factor, βmax, was governed by scaling law analysis using fitting experimental data to identify patterns, trends, and relationships between βmax and the independent variables, Weber (We) numbers, and Reynolds (Re) numbers. The results indicate that liquid viscosity and surface properties affect the droplet's impact and spreading behavior. The Ohnesorge (Oh) numbers significantly influenced the spreading dynamics, while the banana's surface wettability minimally influenced spreading. The prediction model reasonably agrees with all the data in the literature since the R2 = 0.958 is a powerful goodness-of-fit indicator for predicting the spreading factor. It scaled with βmax=a+0.04We.Re1/3, where the "a" constants depend on Oh numbers.

Development of PLA/Lignin Bio-Composites Compatibilized by Ethylene Glycol Diglycidyl Ether and Poly (ethylene glycol) Diglycidyl Ether

Poly (lactic acid) (PLA) is a promising green substitute for conventional petroleum-based plastics in a variety of applications. However, the wide application of PLA is still limited by its disadvantages, such as slow crystallization rate, inadequate gas barrier, thermal degradation, etc. In this study, lignin (1, 3, 5 PHR) was incorporated into PLA to improve the thermal, mechanical, and barrier properties of PLA. Two low-viscosity epoxy resins, ethylene glycol diglycidyl ether (EGDE) and poly (ethylene glycol) diglycidyl ether (PEGDE), were used as compatibilizers to enhance the performance of the composites. The addition of lignin improved the onset degradation temperature of PLA by up to 15 °C, increased PLA crystallinity, improved PLA tensile strength by approximately 15%, and improved PLA oxygen barrier by up to 58.3%. The addition of EGDE and PEGDE both decreased the glass transition, crystallization, and melting temperatures of the PLA/lignin composites, suggesting their compatabilizing and plasticizing effects, which contributed to improved oxygen barrier properties of the PLA/lignin composites. The developed PLA/lignin composites with improved thermal, mechanical, and gas barrier properties can potentially be used for green packaging applications.