Biodegradable films based on commercial κ-carrageenan and cassava starch to achieve low production costs

Active starch-based film using polyvinyl alcohol and chlorogenic acid for strawberry preservation: A comparative analysis of mechanical, barrier, and antibacterial properties

The broad application of starch films has been significantly limited by their insufficient hydrophobicity and antibacterial activity. To overcome these challenges, this study developed a new starch film by incorporating polyvinyl alcohol (PVA) and chlorogenic acid. The study explored the impact of PVA polymerization on the physical and functional characteristics of the resulting films, with particular emphasis on enhancing antimicrobial functionality by incorporating chlorogenic acid. Scanning electron microscopy (SEM) and rheological tests demonstrated the excellent compatibility and exceptional film-forming performance. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses validated the presence of intermolecular entanglements and hydrogen bonding within the films. Incorporating PVA with a polymerization degree of 2400 resulted in a contact angle (CA) of 79.81 ± 1.74°, a water absorption capacity (WAC) of 10.29 ± 0.71 %, and a water vapor permeability (WVP) of (0.44 ± 0.11) × 10-11 g × m-1 × s-1 × Pa-1. Notably, the SCP 2488 film exhibited superior mechanical properties, including the highest Young's modulus of 71.29 MPa, tensile strength of 11.77 MPa, and elongation at break of 106.75 %. Additionally, such a modified film displayed enhanced UV-blocking performance and antibacterial efficacy. Consequently, the SCP 2488 film showed great potential for maintaining the freshness and quality of strawberries.

Valorization of raw papaya (Carica papaya) and citrus peels for development of antimicrobial and biodegradable edible film

Most of the food packaging materials used in the market are petroleum-based plastics; such materials are neither biodegradable nor environmentally friendly and require years to decompose. To overcome these problems, biodegradable and edible materials are encouraged to be used because such materials degrade quickly due to the actions of bacteria, fungi, and other environmental effects. The present study examined that starch can be effectively used as raw material to develop biodegradable, edible films. In this regard, Raw papaya and Citrus Peel were chosen to make biodegradable plastic film blended with corn starch. Raw papaya powder was combined with citrus peel powder for the development of film in treatments of T1, T2, T3, T4 and T5. RPP and CPP blend with Corn starch (CS) to maximize the film-forming properties and characteristics. The films were subjected to various parameter analysis like thickness, optical properties and barrier properties. As per the results, T3 was an optimized film, as it had minimum thickness (0.26 ± 0.01), high tensile strength (5.79 ± 0.12), elongation at break of 11.92 ± 0.03, High transparency (1.42 ± 0.06), and high degradation temperature. From the results, it is inferred that the prepared films are ideally suitable for food packaging and their production on a larger scale can considerably cut down the plastic wastage.

Gelatin-chitosan interactions in edible films and coatings doped with plant extracts for biopreservation of fresh tuna fish products: A review

The preservation of tuna fish products, which are extremely perishable seafood items, is a substantial challenge due to their instantaneous spoilage caused by microbial development and oxidative degradation. The current review explores the potential of employing chitosan-gelatin-based edible films and coatings, which are enriched with plant extracts, as a sustainable method to prolong the shelf life of tuna fish products. The article provides a comprehensive overview of the physicochemical properties of chitosan and gelatin, emphasizing the molecular interactions that underpin the formation and functionality of these biopolymer-based films and coatings. The synergistic effects of combining chitosan and gelatin are explored, particularly in terms of improving the mechanical strength, barrier properties, and bioactivity of the films. Furthermore, the application of botanical extracts, which include high levels of antioxidants and antibacterial compounds, is being investigated in terms of their capacity to augment the protective characteristics of the films. The study also emphasizes current advancements in utilizing these composite films and coatings for tuna fish products, with a specific focus on their effectiveness in preventing microbiological spoilage, decreasing lipid oxidation, and maintaining sensory qualities throughout storage. Moreover, the current investigation explores the molecular interactions associated with chitosan-gelatin packaging systems enriched with plant extracts, offering valuable insights for improving the design of edible films and coatings and suggesting future research directions to enhance their effectiveness in seafood preservation. Ultimately, the review underscores the potential of chitosan-gelatin-based films and coatings as a promising, eco-friendly alternative to conventional packaging methods, contributing to the sustainability of the seafood industry.

Optimized Incorporation of Silver Nanoparticles onto Cotton Fabric Using k-Carrageenan Coatings for Enhanced Antimicrobial Properties

The incorporation of bactericidal properties into textiles is a widely sought-after aspect, and silver nanoparticles (AgNPs) can be used for this. Here, we evaluate a strategy for incorporating AgNPs into a cotton fabric. For this purpose, a bactericidal textile coating based on a composite of AgNPs and kappa-carrageenan (k-CA) was proposed. The composite was obtained by heating the silver precursor (AgNO3) directly in k-CA solution for green synthesis and in situ AgNPs stabilization. Cotton substrates were added to the heated composite solution for surface impregnation and hydrogel film formation after cooling. Direct synthesis of AgNPs on a fabric was also tested. The results showed that the application of a coating based on k-CA/AgNPs composite can achieve more than twice the silver loading on the fabric surface compared to the textile subjected to direct AgNPs incorporation. Furthermore, silver release tests in water showed that higher Ag+ levels were reached for k-CA/AgNPs-coated cotton. Therefore, inoculation tests with the bacteria Staphylococcus aureus (SA) using the agar diffusion method showed that samples covered with the composite resulted in significantly larger inhibition halos. This indicated that the use of the composite as a coating for cotton fabric improved its bactericidal activity against SA.

Synergistic effects of starch and carrageenan from Kappaphycus alvarezii in composite film formation: Physicochemical and degradable properties

Rising concerns around plastic pollution from single-use plastic (SUPs), especially food packaging, have driven interest in sustainable alternatives. As such, algae biomass has gained attention for bioplastic production due to algae's rapid growth and abundant polysaccharides. This research focuses on extracting carrageenan from Kappaphycus alvarezii, extensively cultivated in Sabah, Malaysia, and utilizing it in combination with starch and glycerol to develop algae-based films. The physicochemical properties and degradation rate of these films were evaluated, revealing that the addition of carrageenan enhanced overall thermal stability meanwhile increasing water solubility, water content but reducing the degradation rate and swelling degree. This is primarily due to the crystalline structures of carrageenan, which provide a more rigid arrangement compared to the network of starch polymers. However, the incorporation of starch into the blends has enhanced the elongation and surface morphology, resulting in more balanced properties. Overall, these carrageenan films displayed impressive thermal, mechanical, and biodegradability characteristics, establishing their viability as substitutes for conventional plastics.

Improving physicomechanical properties of arrowroot starch films incorporated with kappa-carrageenan: Sweet cherry coating application

Arrowroot starch (AS)-based films potential is influenced by its low-cost processing and high transparency packaging material but low tensile strength; hence, AS was blended with kappa-carrageenan (KC) to improve mechanical properties of AS-based films and enhance its potential use in food packaging or coating applications. AS-KC-based films were characterized based on structural, physicomechanical, thermal, pasting properties, and coating application in sweet cherry. The films demonstrated high tensile strength from 3.2 to 29.4 MPa and low elongation properties from 160.3 % to 1.9 %. Moreover, AS/KC films exhibited peak viscosities of 18.7 to 34.8 RVU, and thermal analysis depicted lower weight losses (59-45 %) compared to AS-based films (62 %). In addition, sweet cherry samples coated with AS/KC films and stored at 20 °C for 15 days depicted lower weight losses (26.6 %) compared to non-coated samples (>41 %), which indicated the potential use of the film's coating application in extending the shelf life and quality of fresh fruits.

A novel biodegradable film based on chicken gelatin and κ-carrageenan cross-linked with oxidized phenolic compounds

Natural and renewable polymers are gradually replacing petroleum-based plastics, mostly as a result of environmental concerns. Moreover, upcycling industrial food waste into new added-value products is a creative approach that is crucial for cleaner and more sustainable manufacturing. The aim of this study was to obtain an environmentally friendly biodegradable film using a combination of k-carrageenan (KCAR) and chicken gelatin (CGEL), which obtained from poultry by-products. The effects of varying concentrations of KCAR (0-2%) on the physical, permeability, textural, thermal, and microstructural properties of CGEL/KCAR composite films were evaluated. The findings demonstrated that an increase in KCAR enhanced the lightness and opacity levels of the films. Water vapor permeability (WVP) values reduced as the KCAR concentration increased. The lowest WVP value (0.0012 g.mm/h.m2.kpa) was seen in the treatment with 2% KCAR. Tensile strength (TS) values increased with increasing KCAR. The films' thermal stability was increased by the addition of KCAR. Microstructure assessments revealed a more compact and smooth structure in the KCAR-containing treatments, indicating improvements in WVP, thermal stability, and TS. Compared to the commercial cattle gelatin film, the CGEL film had higher TS and lower water solubility (WS). Overall, this study showed that the physical, mechanical, barrier and thermal and microstructural qualities of gelatin-based films may be enhanced by combining CGEL and KCAR to create an effective biodegradable film. Moreover, the comparison study between commercial cattle and chicken gelatin films revealed that cross-linked chicken gelatin films would be a suitable alternative for bovine gelatin films in the production of biodegradable film.

Development of biodegradable film from cactus (Opuntia Ficus Indica) mucilage loaded with acid-leached kaolin as filler

Nowadays, substituting petroleum-based plastics with biodegradable polymers made from polysaccharides loaded with various reinforcing materials has recently gained attention due to the impact of conventional plastics wastes. In this study, polysaccharidic mucilage from Ethiopian cactus (Opuntia Ficus Indica) was derived using microwave-assisted extraction technique to develop biodegradable polymers that were inexpensive, readily available, simple to make, and ecofriendly. The effect of microwave power 300-800 W, solid-liquid (cactus-sodium hydroxide solution) ratio 1:5-1:25, sodium hydroxide concentration 0.1-0.8 mol/L, and extraction time 2-10 min on mucilage extraction were studied and the maximum yield of mucilage was attained at optimized parameters of 506 W, 1:20, 0.606 mol/L, and 9.5 min, respectively. Biodegradable polymers made with mucilage alone have poor mechanical characteristics and are thermally unstable. Thus, to overcome the stated problems, glycerol as a plasticizer and acid-leached kaolin crosslinked with urea as a reinforcing material were used. Moreover, the effect of acid-leached kaolin and glycerol on the physico-chemical properties of the films was studied, and a maximum tensile strength of 6.74 MPa with 18.45 % elongation at break, thermally improved biodegradability of 26 %, were attained at 10 % acid-leached kaolin and 20 % glycerol crosslinking with 2 % urea. But the maximum degradability of 53.5 % was attained at 30 % glycerol content. The control and reinforced biodegradable films were characterized using TGA, FTIR, SEM, and XRD to determine the thermal, functional group, morphology, and crystallinity of the bioplastics, respectively. These biodegradable plastics may be used for packaging application.

Exploring carrageenan: From seaweed to biomedicine-A comprehensive review

Biomaterials are pivotal in the realms of tissue engineering, regenerative medicine, and drug delivery and serve as fundamental building blocks. Within this dynamic landscape, polymeric biomaterials emerge as the frontrunners, offering unparalleled versatility across physical, chemical, and biological domains. Natural polymers, in particular, captivate attention for their inherent bioactivity. Among these, carrageenan (CRG), extracted from red seaweeds, stands out as a naturally occurring polysaccharide with immense potential in various biomedical applications. CRG boasts a unique array of properties, encompassing antiviral, antibacterial, immunomodulatory, antihyperlipidemic, antioxidant, and antitumor attributes, positioning it as an attractive choice for cutting-edge research in drug delivery, wound healing, and tissue regeneration. This comprehensive review encapsulates the multifaceted properties of CRG, shedding light on the chemical modifications that it undergoes. Additionally, it spotlights pioneering research that harnesses the potential of CRG to craft scaffolds and drug delivery systems, offering high efficacy in the realms of tissue repair and disease intervention. In essence, this review celebrates the remarkable versatility of CRG and its transformative role in advancing biomedical solutions.

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.

κ-Carrageenan/poly(vinyl alcohol) functionalized films with gallic acid and stabilized with metallic ions

Given the environmental issues caused by the extensive use of conventional petroleum-based packaging, this work proposes functional films based on commercial κ-carrageenan (κc), poly(vinyl alcohol) (PVA), and gallic acid (GA) prepared by the "casting" method. Metallic ions in the κc composition stabilized the films, supporting processability and suitable mechanical properties. However, the incorporated GA amount (6.25 and 10 wt%) in the films created from an aqueous κc solution at 3.0 % wt/v (κc3) prevented crystalline domains in the resulting materials. The κc3/GA6.25 and κc3/GA10 films had less tensile strength (8.50 ± 0.61 and 10.28 ± 0.65 MPa) and high elongation at break (2.36 ± 0.16 and 1.19 ± 0.17 %) compared to the other samples, respectively. Low κc contents (κc2.5/GA6.25 and κc2.5/GA10) promoted stiff films and less permeability to water vapor (5.36 ± 0.51 and 3.76 ± 0.02 [×10-12 g(Pa × m × s)-1], respectively. The κc/GA weight ratio also influenced the film wettability, indicating water contact angles (WCAs) between 55 and 74°. The surface wettability implies a low oil permeability and high water swelling capacity of up to 1600 %. The κc/GA also played an essential role in the film's antimicrobial action against Staphylococcus aureus and Escherichia coli. Thus, the κc3/GA10 film showed suitable physical, chemical, and biological properties, having the potential to be applied as food coatings.

Starch modification through its combination with other molecules: Gums, mucilages, polyphenols and salts

Apart from its non-toxicity, biocompatibility and biodegradability, starch has demonstrated eminent functional characteristics, e.g., forming well-defined gels/films, stabilizing emulsions/foams, and thickening/texturizing foods, which make it a promising hydrocolloid for various food purposes. Nonetheless, because of the ever-increasing range of its applications, modification of starch via chemical and physical methods for expanding its capabilities is unavoidable. The probable detrimental impacts of chemical modification on human health have encouraged scientists to develop potent physical approaches for starch modification. In this category, in recent years, starch combination with other molecules (i.e., gums, mucilages, salts, polyphenols) has been an interesting platform for developing modified starches with unique attributes where the characteristics of the fabricated starch could be finely tuned via adjusting the reaction parameters, type of molecules reacting with starch and the concentration of the reactants. The modification of starch characteristics upon its complexation with gums, mucilages, salts, and polyphenols as common ingredients in food formulations is comprehensively overviewed in this study. Besides their potent impact on physicochemical, and techno-functional attributes, starch modification via complexation could also remarkably customize the digestibility of starch and provide new products with less digestibility.

A Review on Biopolymer-Based Biodegradable Film for Food Packaging: Trends over the Last Decade and Future Research

In recent years, much attention has been paid to the use of biopolymers as food packaging materials due to their important characteristics and properties. These include non-toxicity, ease of availability, biocompatibility, and biodegradability, indicating their potential as an alternative to conventional plastic packaging that has long been under environmental scrutiny. Given the current focus on sustainable development, it is imperative to develop studies on biopolymers as eco-friendly and sustainable food packaging materials. Therefore, the aim of this review is to explore trends and characteristics of biopolymer-based biodegradable films for food packaging, analyze the contribution of various journals and cooperation between countries, highlight the most influential authors and articles, and provide an overview of the social, environmental, and economic aspects of biodegradable films for food packaging. To achieve this goal, a bibliometric analysis and systematic review based on the PRISMA method were conducted. Relevant articles were carefully selected from the Scopus database. A bibliometric analysis was also conducted to discuss holistically, comprehensively, and objectively biodegradable films for food packaging. An increasing interest was found in this study, especially in the last 3 years with Brazil and China leading the number of papers on biodegradable films for food packaging, which were responsible for 20.4% and 12.5% of the published papers, respectively. The results of the keyword analysis based on the period revealed that the addition of bioactive compounds into packaging films is very promising because it can increase the quality and safety of packaged food. These results reveal that biodegradable films demonstrate a positive and promising trend as food packaging materials that are environmentally friendly and promote sustainability.

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

Biopolymer-based packaging materials have become of greater interest to the world due to their biodegradability, renewability, and biocompatibility. In recent years, numerous biopolymers-such as starch, chitosan, carrageenan, polylactic acid, etc.-have been investigated for their potential application in food packaging. Reinforcement agents such as nanofillers and active agents improve the properties of the biopolymers, making them suitable for active and intelligent packaging. Some of the packaging materials, e.g., cellulose, starch, polylactic acid, and polybutylene adipate terephthalate, are currently used in the packaging industry. The trend of using biopolymers in the packaging industry has increased immensely; therefore, many legislations have been approved by various organizations. This review article describes various challenges and possible solutions associated with food packaging materials. It covers a wide range of biopolymers used in food packaging and the limitations of using them in their pure form. Finally, a SWOT analysis is presented for biopolymers, and the future trends are discussed. Biopolymers are eco-friendly, biodegradable, nontoxic, renewable, and biocompatible alternatives to synthetic packaging materials. Research shows that biopolymer-based packaging materials are of great essence in combined form, and further studies are needed for them to be used as an alternative packaging material.

Production and Characterization of k-Carrageenan Films Incorporating Cymbopogon winterianus Essential Oil as New Food Packaging Materials

The global production of synthetic plastics from petroleum-based raw ingredients exceeds 150 million metric tons. The environment is threatened by tons of plastic waste, thus endangering wildlife and the public's health. These consequences increased the interest in biodegradable polymers as potential substitutes for traditional packaging materials. This study aimed to produce and characterize k-carrageenan films incorporating Cymbopogon winterianus essential oil, in which citronellal was determined to be the major compound (41.12%). This essential oil presented remarkable antioxidant activity, as measured through DPPH (IC₅₀ = 0.06 ± 0.01%, v/v; AAI = 85.60 ± 13.42) and β-carotene bleaching (IC₅₀ = 3.16 ± 0.48%, v/v) methods. The essential oil also showed antibacterial properties against Listeria monocytogenes LMG 16779 (diameter of inhibition zone = 31.67 ± 5.16 mm and MIC = 8 µL/mL), which were also observed when incorporated in the k-carrageenan films. Moreover, scanning electron microscopy showed the reduction of the biofilms of this bacterium, and even its inactivation, due to visible destruction and loss of integrity when the biofilms were created directly on the developed k-carrageenan films. This study also revealed the quorum sensing inhibition potential of Cymbopogon winterianus essential oil (diameter of violacein production inhibition = 10.93 ± 0.81 mm), where it could impede intercellular communication and, hence, lower violacein synthesis. The produced k-carrageenan films were transparent (>90%) and slightly hydrophobic (water contact angle > 90°). This work demonstrated the viability of using Cymbopogon winterianus essential oil to produce k-carrageenan bioactive films as new food packaging materials. Future work should focus on the scale-up production of these films.

Degradable Carrageenan as a Substrate and Resistive Material for Flexible Applications

In recent years, due to the environmental impact caused by electronic waste, decomposable components have become one of the most important topics in the world. In this study, the carrageenan material extracted from red algae was used as the resistance-switching layer of electronic components, and potassium was added to the carrageenan as a substrate (CK). CK has the advantages of excellent mechanical properties, transparency, and decomposability. In addition, the In/carrageenan/Ag/CK (ICACK) device exhibits good memory properties with a high ON/OFF ratio exceeding 10⁷ and a retention time exceeding 10⁴ s. Due to the doping of potassium ions, the ICACK element has a fairly good bending performance. Although bending or stretching under a small radius of curvature will not have a great impact on the electrical performance, it shows that in the future wearable or good potential in the field of implantable devices.

Cassava starch films for food packaging: Trends over the last decade and future research

Cassava starch is one of the most available and cost-effective biopolymers. This work aimed to apply a bibliometric methodology to identify the most impactful scientific data on cassava starch and its residues for food packaging in the last ten years. As a result, an increasing interest in this subject has been observed, mainly in the past five years. Among the 85 selected scientific publications, Brazil and China have been leading the research on starch-based films, accounting for 39 % of the total. The International Journal of Biological Macromolecules was the main scientific source of information. Besides cassava starch, 41.18 % of these studies added other biopolymers, 5.88 % added synthetic polymers, and 4.71 % added a combination of both. Studies analyzed suggested that different modifications in starch can improve films' mechanical and barrier properties. In addition, 52.94 % of articles evaluated the film's bioactivity. Still, only 37.65 % assessed the performance of those films as food packaging, suggesting that more studies should be conducted on assessing the potential of these alternative packages. Future research should consider scale-up methods for film production, including cost analysis, assessment life cycle, and the impact on the safety and quality of a broader range of foods.

Recent advances in carrageenan-based films for food packaging applications

In order to solve the increasingly serious environmental problems caused by plastic-based packaging, carrageenan-based films are drawing much attentions in food packaging applications, due to low cost, biodegradability, compatibility, and film-forming property. The purpose of this article is to present a comprehensive review of recent developments in carrageenan-based films, including fabrication strategies, physical and chemical properties and novel food packaging applications. Carrageenan can be extracted from red algae mainly by hydrolysis, ultrasonic-assisted and microwave-assisted extraction, and the combination of multiple extraction methods will be future trends in carrageenan extraction methods. Carrageenan can form homogeneous film-forming solutions and fabricate films mainly by direct coating, solvent casting and electrospinning, and mechanism of film formation was discussed in detail. Due to the inherent limitations of the pure carrageenan film, physical and chemical properties of carrageenan films were enhanced by incorporation with other compounds. Therefore, carrageenan-based films can be widely used for extending the shelf life of food and monitoring the food freshness by inhibiting microbial growth, reducing moisture loss and the respiration, etc. This article will provide useful guidelines for further research on carrageenan-based films.

A Comprehensive Characterization of Biodegradable Edible Films Based on Potato Peel Starch Plasticized with Glycerol

Potatoes are a source of starch, which is an eco-friendly alternative to petrochemicals in plastic production. Increasing potato production also creates agricultural waste that could be converted to potato peel starch (PPS) and developed as films. A response surface method approach was employed to optimize the bioconversion of PPS (2, 4, and 6% w/v) and compared with carboxymethyl cellulose (CMC)-based films. The microstructure analysis of PPSF showed increased thickness, decreased swelling power, water solubility, and vapor permeability, which were linked to increased molecular interactions as a function of PPS increments. However, low-starch PPSF exhibited high transparency, good mechanical properties, and thermal stability (high melting temperature), pliability, and accelerated seawater and soil biodegradation (~90%: 20 and 50 days, respectively). All films exhibited thermal stability at >100 °C and retained similar amorphous characteristics, evidenced by their flexibility, which confirmed the potential use for PPS in packaging perishable and cooled foods.

Polysaccharides: Sources, Characteristics, Properties, and Their Application in Biodegradable Films

Biodegradable films emerge as alternative biomaterials to conventional packaging from fossil sources, which, in addition to offering protection and increasing the shelf life of food products, are ecologically sustainable. The materials mostly used in their formulation are based on natural polysaccharides, plasticizing agents, and bioactive components (e.g., antimicrobial agents or antioxidants). The formulation of biodegradable films from polysaccharides and various plasticizers represents an alternative for primary packaging that can be assigned to specific food products, which opens the possibility of having multiple options of biodegradable films for the same product. This review describes the main characteristics of the most abundant polysaccharides in nature and highlights their role in the formulation of biodegradable films. The compilation and discussion emphasize studies that report on the mechanical and barrier properties of biodegradable films when made from pure polysaccharides and when mixed with other polysaccharides and plasticizing agents.

Natural carbohydrate-based thermosensitive chitosan/pectin adsorbent for removal of Pb(II) from aqueous solutions

Biodegradable and eco-friendly adsorbents composed of natural carbohydrates have been used to replace carbon-based materials. This study presents a natural carbohydrate-based chitosan/pectin (CS/Pec) hydrogel adsorbent to remove Pb(II) from aqueous solutions. The physical CS/Pec hydrogel was prepared by blending aqueous CS and Pec solutions at 65 °C, preventing the use of toxic chemistries (crosslinking agents). The thermosensitive CS/Pec hydrogel was quickly created by cooling CS/Pec blend at room temperature. The used strategy created stable CS/Pec hydrogel against disintegration and water dissolution. The as-prepared hydrogel was characterized by infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The adsorbent had 1.688 mmol -COO^- for each gram. These ionized sites bind Pb(II) ions, promoting their adsorption. The adsorption kinetic and equilibrium studies indicated that the Elovich and pseudo-second-order models adjusted well to the experimental data, respectively. The maximum removal capacities (q_m) predicted by the Langmuir and Sips isotherms achieved 108.2 and 97.55 mg/g at 0.83 g/L adsorbent dosage (pH 4.0). The hydrogel/Pb(II) pair was characterized by scanning electron microscopy (SEM), X-ray dispersive energy (EDS), and differential scanning calorimetry (DSC). The chemisorption seems to play an essential role in the Pb(II) adsorption. Therefore, the adsorbent was not recovered, showing low potential for reusability.

Preparation and Characterization of Super-Absorbing Gel Formulated from κ-Carrageenan-Potato Peel Starch Blended Polymers

κ-carrageenan is useful for its superior gelling, hydrogel, and thickening properties. The purpose of the study was to maximize the hydrogel properties and water-absorbing capacity of κ-carrageenan by blending it with starch from potato peels to be used as safe and biodegradable water-absorbent children’s toys. The prepared materials were analyzed using FTIR and Raman spectroscopy to analyze the functional groups. Results showed that there was a shift in the characteristic peaks of starch and κ-carrageenan, which indicated their proper reaction during blend formation. In addition, samples show a peak at 1220 cm⁻¹ corresponding to the ester sulfate groups, and at 1670 cm⁻¹ due to the carbonyl group contained in D-galactose. SEM micrographs showed the presence of rough surface topology after blending the two polymers, with the appearance of small pores. In addition, the presence of surface cracks indicates the biodegradability of the prepared membranes that would result after enzymatic treatment. These results are supported by surface roughness results that show the surface of the κ-carrageenan/starch membranes became rougher after enzymatic treatment. The hydrophilicity of the prepared membranes was evaluated from contact angle (CA) measurements and the swelling ratio. The swelling ratio of the prepared membranes increased gradually as the starch ratio increased, reaching 150%, while the water-uptake capacity increased from 48 ± 4% for plain κ-carrageenan to 150 ± 5% for 1:2 κ-carrageenan/starch blends. The amylase enzyme showed an effective ability to degrade both the plain κ-carrageenan and κ-carrageenan/starch membranes, and release glucose units for up to 236 and 563, respectively. According to these results, these blends could be effectively used in making safe and biodegradable molded toys with superior water-absorbing capabilities.

Characterization of a natural biodegradable edible film obtained from arrowroot starch and iota-carrageenan and application in food packaging

Future food packaging trends are shifting to natural and eco-friendly materials developed from biopolymers such as starch and other hydrocolloids, to reduce pollution from synthetic polymers. Arrowroot starch (AS) (3.5, 3, 2.5, and 2%) and iota-carrageenan (IC) (0.5, 1, 1.5, and 2%) were blended to develop biodegradable edible films (AS/IC-BEF), which were compared against AS-BEF (4%, control). All films were characterized based on their physico-mechanical and barrier properties, functional group properties, crystallinity properties, thermal properties, and soil and seawater biodegradation. AS-BEF exhibited smooth surface, high transparency, and completed composting soil biodegradation in 7 days whereas AS/IC-BEF samples exhibited higher tensile strength, water solubility, swelling properties, and barrier properties, but completed biodegradation after 30 days. XRD analysis indicated IC fractions contributed to increase in degree of crystallinity (28.35°) and FTIR signaled strong hydrogen bond interactions between polymers. AS/IC-BEF samples demonstrated melting temperatures between 158 and 190 °C while glass transition temperatures ranged from 153 to 176 °C, which resulted in maximum weight loss around 50-55% at melting temperatures. Finally, AS/IC-BEF samples successfully inhibited weight loss of cherry tomatoes at room temperature and extended their shelf life to 10 days, which indicated that the AS/IC composite material produced a BEF with potential food and industrial applications.

Composite biopolymer films based on a polyelectrolyte complex of furcellaran and chitosan

The aim of research was to develop biopolymer films based on natural polysaccharides. For the first time, biodegradable films were obtained on the basis of a furcellaran-chitosan polyelectrolyte complex. The conditions for its formation were determined by measuring the zeta potential as a function of colloid pH, the size of pure components and their mixtures. The structure and morphology of the prepared films were characterised by FT-IR and AFM analysis. The lowest WVTR values were observed for the FUR and the CHIT-FUR films at the ratio of 9:1. The mechanical, water and rheological properties depend on the weight ratio of furcellaran to chitosan in the mixture. The thermal stability has been improved in CHIT-FUR films at the 9:1 ratio. The results obtained create the possibility of successfully using CHIT-FUR films in the development of biodegradable packaging materials.

Bio-based multilayer films: A review of the principal methods of production and challenges

The development of biodegradable packaging materials has been drawing attention worldwide to minimize the environmental impact of traditional petroleum-based plastics. Nevertheless, it is challenging to obtain bio-based materials with suitable properties for packaging applications. Films produced from a single biopolymer often lack some important properties. An alternative to overcome this limitation is the multilayer assembly. Under this technology, two or more materials with specific and complementary properties are combined into a single-layered structure, thus improving the performance of bio-polymer plastics. This review presents the main aspects of bio-based multilayer film production technologies, discussing their advantages and disadvantages, which have to be considered to produce the most suitable film for each specific application. Most of the studies reported that such films resulted in increased mechanical performance and decreased water, oxygen, and dioxide carbon permeability. This approach allows the addition of compounds leading to antioxidant or antibacterial activity. Finally, a discussion about the future challenges is also presented.

Preparation and Characterization of κ-Carrageenan Modified with Maleic Anhydride and Its Application in Films

In this work, the physicochemical properties of maleic anhydride (MAH)-modified κ-carrageenan (κCar) (MC) were characterized and compared with those of native κ-carrageenan (NC). The Fourier transform infrared spectrum of MC exhibited that κCar was successfully modified. Thermogravimetric analysis indicated that the thermal stability of MC was decreased. When the degree of substitution was 0.032, MC exhibited a low gel strength (759 g/cm²), gelling temperature (33.3 °C), and dehydration rate (60.3%). Given the excellent film-forming ability of κCar, MC films were then prepared and were found to have better mechanical and barrier properties (UV and water) than NC films. With regard to optical properties, MC films could completely absorb UV light in the range of 200–236 nm. The water contact angle of MC films was higher than that of NC films. Moreover, the elongation at break increased from 26.9% to 163%. These physicochemical property changes imply that MC can be employed in polysaccharide-based films.

Low Molecular Weight Kappa-Carrageenan Based Microspheres for Enhancing Stability and Bioavailability of Tea Polyphenols

Tea polyphenols (TP) are a widely acknowledged bioactive natural product, however, low stability and bioavailability have restricted their application in many fields. To enhance the stability and bioavailability of TP under certain moderate conditions, encapsulation technique was applied. Kappa–Carrageenan (KCG) was initially degraded to a lower molecular weight KCG (LKCG) by H2O2, and was selected as wall material to coat TP. The obtained LKCG (Mn = 13,009.5) revealed narrow dispersed fragments (DPI = 1.14). FTIR and NMR results demonstrated that the main chemical structure of KCG remained unchanged after degradation. Subsequently, LK-CG and TP were mixed and homogenized to form LK-CG-TP microspheres. SEM images of the microspheres revealed a regular spherical shape and smooth surface with a mean diameter of 5–10 μM. TG and DSC analysis indicated that LK-CG-TP microspheres exhibited better thermal stability as compared to free TP. The release profile of LK-CG-TP in simulated gastric fluid (SGF) showed a slowly release capacity during the tested 180 min with the final release rate of 88.1% after digestion. Furthermore, in vitro DPPH radical scavenging experiments revealed that LK-CG-TP had an enhanced DPPH scavenging rate as compared to equal concentration of free TP. These results indicated that LK-CG-TP microspheres were feasible for protection and delivery of TP and might have extensive potential applications in other bioactive components.

Preparation and characterization of k-carrageenan/konjac glucomannan/TiO2 nanocomposite film with efficient anti-fungal activity and its application in strawberry preservation

A nano-composite film was prepared from k-carrageenan (KC), konjac glucomannan (KGM) and TiO₂ nanoparticles (NPs) by solvent casting method. The morphology and structure of the KC/KGM based nano-composite films prepared from different weight ratio of TiO₂ NPs were characterized by SEM, XRD and FT-IR techniques. The addition of TiO₂ NPs to KC/KGM films improved the mechanical, thermal, structural, and barrier properties of nano-composite films. In particular, the film containing 7 wt% of TiO₂ NPs exhibited effective photocatalytic anti-fungal activity (79%) for Penicillium viridicatum after irradiating 6 h through generating reactive oxygen species thus destroying the fungi. Benefitting from the improved characteristics investigated above, the nano-composite films showed a favorable effect on strawberry storage. Overall, the fabricated KC/KGM/TiO₂ nano-composite films have a broad application in the field of food preservation and packaging applications.

Effect of the incorporation of lignin microparticles on the properties of the thermoplastic starch/pectin blend obtained by extrusion

The present study aimed to produce thermoplastic starch films with different concentrations of thermoplastic pectin and the addition of 4% lignin microparticles as a reinforcing and active agent. The pectin improved the modulus of elasticity, and decreased the elongation at break. In addition, it improved the UV light protection to 100% at 320 nm and 95.9% at 400 nm. The incorporation of lignin microparticles improved the thermal stability of the blends made with 25% and 50% thermoplastic pectin when compared to the pectin-free blends. The blend with 25% thermoplastic pectin led to an increase of 75.8% and 34% in elongation at break and deformation of the films, respectively. This blend also improved the UV light protection to 100% due to its dark brown color. Regarding the permeability properties, the films with 25% and 50% thermoplastic pectin showed lower oxygen permeability (48% and 65%) and an increase in the antioxidant activities from 2.7% to 71.08% and 4.1% to 79.28%, respectively. Thus, the polymer blend with 25% thermoplastic pectin with the incorporation of lignin microparticles proved to be a good alternative for use in foods sensitive to the effects of oxygen and UV light.

Bactericidal Pectin/Chitosan/Glycerol Films for Food Pack Coatings: A Critical Viewpoint

Pectin and chitosan films containing glycerol (Gly) at 5, 10, 15, 20, 30, and 40 wt % were prepared in an aqueous HCl solution (0.10 M) by the solvent evaporation method. The unwashed film (UF) containing 40 wt % Gly (UF40) had elongation at break (ε, %) of 19%. Washed films (WFs) had high tensile strength (σ > 46 MPa) and low elongation at break (ε, <5.0%), enabling their use in food packaging applications. The polymers’ self-assembling occurred during the washing, increasing the stiffness. The XPS analysis suggests that some HCl is lost during the drying process, resulting in a low acid content on the UF surfaces. The UF40 (at 5.0 mg/mL) exhibits cytocompatibility toward mammalian cells and antimicrobial and anti-adhesive properties against Escherichia coli. The remaining HCl in the UF40 can be a disadvantage for food packaging applications; the UF40 (∅ = 8.5 mm; 55 μm thickness) releases H₃O⁺/HCl, reducing the pH to approximately 3.0 when kept in 200 mL distilled water for approximately 30 min. Therefore, we propose the use of UF40 to coat commercial food packaging. The UF40 has low permeability to water vapor and oxygen and works as a barrier against ultraviolet light. The UF40 is also colorless and completely transparent. The UF40 maintained tomatoes’ structural integrity for 18 days at room temperature with no oxidation or microorganism contamination. This paper presents a critical viewpoint concerning chitosan-based films with antimicrobial activities.