Biopolymer-Based Films from Sodium Alginate and Citrus Pectin Reinforced with SiO2

Myrrh Oleo-Gum Resin as a Functional Additive in Pectin and κ-Carrageenan Composite Films for Food Packaging

Myrrh oleo-gum-resin (MOGR) is a natural substance that has a rich history of medicinal use due to its anti-inflammatory, antimicrobial, and antioxidant properties. The present study reports on the fabrication and assessment of pectin and K-carrageenan composite films infused with varying proportions (0.3%, 0.5%, and 0.7%) of MOGR. Morphological analysis of the film samples was conducted using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results indicated that the introduction of MOGR led to a notable increase in surface roughness. The SEM micrographs of the films showed that the MOGR addition had an important effect on the microstructure of the film. The surface hydrophobicity of the MOGR-loaded films increased, as confirmed by the rise in the contact angle. Moreover, there was an increase in the thickness (0.062 ± 0.004-0.095 ± 0.006 mm) and opacity (1.24 ± 0.07-9.41 ± 0.24) of the films with the addition of MOGR; however, tensile strength (7.30 ± 0.50-4.92 ± 0.34 MPa), elongation at break (32.41% ± 1.0%-29.70% ± 0.24%), and barrier properties decreased. Additionally, a rise in MOGR concentration corresponded to a rise in overall color difference ΔE (0.77 ± 0.03-5.09 ± 0.49) of the films. Notably, the incorporation of MOGR led to an increase in the antioxidant activity of the composite films, indicating potential applications in functional packaging materials.

Tuning the structure and physiochemical properties of sodium alginate and chitosan composite films through sodium tripolyphosphate (STPP) crosslinking

Sodium tripolyphosphate (STPP), an inorganic and non-toxic polyphosphate, has potential applications as a crosslinking agent in the fabrication of edible films. This study utilized STPP in the development of sodium alginate-chitosan composite films, with a focus on their suitability for food packaging applications. The results indicate that the incorporation of STPP led to an increase in film thickness (from 0.048 ± 0.004 to 0.078 ± 0.008 mm), elongation at break (from 11.50 ± 1.49 % to 15.88 ± 2.14 %), water permeation (from 0.364 ± 0.010 to 0.521 ± 0.021 gmm/(m2h*kPa)), and moisture content (from 25.98 ± 0.20 % to 28.12 ± 0.17 %). In contrast, there was a decrease in tensile strength (from 30.23 ± 2.08 to 25.60 ± 1.22 MPa) and swelling index (from 752.9 ± 17.1 to 533.5 ± 8.9 %). Scanning electron microscopy (SEM) analysis revealed the formation of distinctive needle-like microcrystals with the incorporation of STPP. Fourier-transform infrared spectroscopy (FTIR) analysis indicated intermolecular interactions between STPP and the film-forming biopolymers. The data obtained from Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) demonstrated enhanced thermal stability of STPP-loaded films at elevated temperatures. Furthermore, the films exhibited increased DPPH scavenging activity with the addition of STPP. This study underscores the potential of STPP as a crosslinking agent for the development of composite edible films, suggesting applications in the field of food packaging.

Pectin/sodium alginate films tailored with Acetyl-11-keto-beta-boswellic acid for active packaging

The present study aimed to develop food packaging films by using a combination of pectin (PE) and sodium alginate (SA) enriched with Acetyl-11-keto-beta-boswellic acid (AKBA) as a functional or active ingredient. The fabricated films underwent comprehensive evaluation of their morphological, chemical, mechanical, barrier, optical, thermal, antioxidant, and antimicrobial properties. SEM and FTIR analysis showed that AKBA had good compatibility with film-forming components. The AKBA-loaded film samples exhibited a decrease in their barrier properties and tensile strength, but enhancements in both elongation at break and thickness values was observed. With the addition of AKBA, a significant increase (p < 0.05) in the ultraviolet barrier properties of the films and total colour variation (ΔE) was observed. TGA analysis of the films unveiled an improvement in thermal resistance with the incorporation of AKBA. Moreover, the films loaded with AKBA exhibited potent antioxidant activity in the ABTS and DPPH assay methods. Disk diffusion analysis showed the antimicrobial activity of AKBA-loaded films against P. aeruginosa, highlighting the potential of AKBA as a natural antimicrobial agent for the safety of food products. The results demonstrate the practical application of PE and SA active films loaded with AKBA, particularly within the food packaging industry.

Limonene and its derived oligomer as bioactive additives in starch/coffee husks biocomposites for food packaging applications

In this study, antioxidant, and antimicrobial starch-based biocomposite films reinforced with coffee husks (S/CH) were developed by incorporating either limonene (LM) (S/CH/LM) or its oligomer derivative, poly(limonene) (PLM) (S/CH/PLM), at different concentrations (5-10 % w/w of starch). Through a comprehensive assessment of film properties, morphology, and structure, a comparative analysis between the two additives was proposed. Scanning electron microscopy (SEM) revealed some defects throughout the polymer matrix after additive incorporation. The tensile strength (TS) and modulus of elasticity (ME) showed a decrease upon the inclusion of both LM and PLM, while the elongation at break (E) increased. Notably, PLM exhibited outstanding antioxidant capacity, enhancing the films by 108 % over control samples. Additionally, at just 5 % concentration, PLM effectively inhibited the growth of Escherichia coli ATCC 11775 (35.33 ± 2.52 mm) and demonstrated an impressive UV-Vis barrier, comparable to the highest amount of LM incorporated. Therefore, this research highlights the potential of coffee husk-reinforced starch biocomposites with limonene-derived additives as a promising solution for food packaging applications. The comparative analysis sheds light on the advantages of using the PLM in terms of antioxidant and antimicrobial properties, contributing to the advancement of active packaging technologies.

Zinc oxide nanoparticle-reinforced pectin/starch functionalized films: A sustainable solution for biodegradable packaging

Environmental pollution caused by non-biodegradable plastic pollutants adversely affects various ecosystems. This study proposes the development of novel functional and biodegradable films based on corn starch (CST) and pectin (PEC) containing zinc oxide nanoparticles (ZnONPs) from the casting method. The films exhibited processability, transparency, low water vapor permeation, and desirable mechanical properties for food packaging and coating applications. The ZnONPs acted as a plasticizer, enhancing the film elongation at the break, increasing the pec25-1 (PEC 25 wt% and ZnONPs 1 wt%) elongation from 79.85 to 162.32 %. The improved film elasticity supported by ZnONPs reduced the material stiffness. However, the films still demonstrated an average tensile strength (0.69 MPa) 17-fold higher than the tensile strength (0.04 MPa) of the non-biodegradable commercial film based on poly(vinyl chloride). Furthermore, the ZnONPs enhanced the UV-blocking capabilities of the films, leading to wettable materials with water contact angles lower than 90°. The films showed high biodegradation rates under natural disposal conditions. The results indicated that the pec25-1/ZnONPs film is a promising eco-friendly coating in food preservation due to its biodegradability, suitable mechanical properties, low water vapor permeability, and UV-blocking properties.

Recent progress in pectin extraction and their applications in developing films and coatings for sustainable food packaging: A review

Perishable foods like fruits and vegetables, meat, fish, and dairy products have short shelf-life that causes significant postharvest losses, which poses a major challenge for food supply chains. Biopolymers have been extensively studied as sustainable alternatives to synthetic plastics, and pectin is one such biopolymer that has been used for packaging and preservation of foods. Pectin is obtained from abundantly available low-cost sources such as agricultural or food processing wastes and by products. This review is a complete account of pectin extraction from agro-wastes, development of pectin-based composite films and coatings, their characterizations, and their applications in food packaging and preservation. Compared to conventional chemical extraction, supercritical water, ultrasound, and microwave assisted extractions are a few examples of modern and more efficient pectin extraction processes that generate almost no hazardous effluents, and thus, such extraction techniques are more environment friendly. Pectin-based films and coatings can be functionalized with natural active agents such as essential oils and other phytochemicals to improve their moisture barrier, antimicrobial and antioxidant properties. Application of pectin-based active films and coatings effectively improved shelf-life of fresh cut-fruits, vegetables, meat, fish, poultry, milk, and other food perishable products.

Formation and Investigation of Physicochemical and Microbiological Properties of Biocomposite Films Containing Turmeric Extract Nano/Microcapsules

In the era of growing plastic consumption, food waste by consumers and overproduction caused by economic reasons, the global goal is to decrease these phenomena. Biocomposite films investigated in the past years are creating a promising future toward ecological, intelligent and active packaging. Due to their unique properties, they can be used in many areas of our life and reduce the constantly increasing pollution of our planet. The aim of our study was to obtain innovative and flexible biopolymer films based on sodium alginate and chitosan, as well as to develop methods for generating nanocapsules with turmeric extract in them. Bionanocomposites were analyzed using UV-VIS, FTIR, photoluminescence spectroscopy and SEM microscopy, while contact angles, surface free energy, particle size (DLS) and zeta potential were determined. The mechanical and colorimetric properties of the produced films were investigated, and the water content, solubility and water absorption were determined. Microbiological tests were carried out to analyze the influence of the produced films on the development of microorganisms. The results of the performed analyses allowed us to confirm the presence of curcumin nano- and microcapsules in the alginate-chitosan composite. Moreover, studies have shown that the structure of polysaccharides does not change during capsule manufacturing. The film with the highest concentration of the capsules showed better parameters in tests of solubility, water content, degree of swelling and mechanical properties. The obtained properties of the developed films allow them to be used as active and intelligent packaging materials, or as their parts.