Preparation of novel seaweed nanocomposite film from brown seaweeds Laminaria japonica and Sargassum natans

Development and characterization of carrageenan/nanocellulose/silver nanoparticles bionanocomposite film from Kappaphycus alvarezii seaweed for food packaging

This study focuses on developing seaweed-based bionanocomposite films using carrageenan (Cr) as the matrix with nanocellulose (NC) as reinforcing material and silver nanoparticles (AgNPs) as antimicrobial agent, all sourced from Kappaphycus alvarezii seaweed. The Cr/NC/AgNPs bionanocomposite films were created using a solvent casting technique and comprehensively characterized to assess their suitability for food packaging applications. The addition of NC and AgNPs significantly improved the mechanical properties, with a maximum load of 16.73 N, tensile strength of 6.81 MPa, elastic modulus of 32.18 MPa, and elongation at break of 18.73 %. The films exhibited excellent optical properties and enhanced moisture barrier performance, with a water vapor transmission rate of 5.62 g/m2d, moisture content of 11.09 %, moisture uptake of 85.98 %, and water solubility of 47.7 %. Thermal analysis showed improved stability, with decomposition temperatures up to 282 °C. The films biodegraded completely within 15 days. Storage tests on bread as a food model demonstrated the films' antimicrobial efficacy, preventing mold growth for one month. Silver ion migration (0.013 μg/g) was well below the safety limit (0.05 μg/g). These results highlight the potential of Cr/NC/AgNPs bionanocomposite films as sustainable, functional materials for food packaging.

Physicochemical aspects of hydrogel preparation from algal cellulose

Brown algae represent a valuable and promising source of cellulosic materials due to their high productivity and widespread, low cultivation cost and ease of processing, attributable to the absence of lignin. The aforementioned advantages are accompanied by the unique properties of algal cellulose (low degree of polymerization and an Iα-type crystal cell structure) due to the peculiarities of biosynthesis. These properties render algae superior to higher plants in terms of producing pure, mesoporous cellulosic materials, e.g. gels. The aim of this study is to first time evaluate the hydration capacity of algal cellulose and nanocellulose during hydrogel formation. Employing FTIR spectroscopy, calorimetry, and nuclear magnetic resonance relaxometry, we explored the interaction of algal cellulose and nanocellulose with water. Nanocellulose has a higher content of free water owing to its developed mesoporous structure. The interaction between cellulose and water is exothermic, liberating heat at 7.2-29.2 J/g d.w. The high moisture retention capacity (37 g/g), coupled with the small size of nanocrystals, facilitates the formation of a stable homogeneous algal nanocellulose hydrogel, which remains stable over extended storage periods. This resultant hydrogel has promising applications in biomedical material production, including wound dressings, anti-adhesive films, and abdominal surgery gels.

Influence of alginate extraction conditions from the brown seaweed Dictyota mertensii on the functional properties of a novel glycerol plasticized alginate film

Alginate films were prepared from the brown seaweed Dictyota mertensii using glycerol as a plasticizer. The effects of extraction conditions-time, temperature, and Na2CO3 concentration-on the optical, barrier, and mechanical properties of the films were investigated using a central composite design (CCD). ANOVA and F tests confirmed the models' statistical significance at p ≤ 0.05, 95 % CI. Na2CO3 concentration significantly influenced moisture absorption, water vapor permeability, solubility, opacity, L*, b*, and elongation at break. Temperature mainly affected the color parameter a* and tensile strength, while time was more relevant for the modulus of elasticity. The properties of alginate from Dictyota mertensii were correlated to the film properties. Optimization through numerical desirability function yielded a global desirability index of 0.767, with optimal conditions at 1.390 h, 54.927 °C, and 0.361 mol.L-1 Na2CO3. Under these conditions, the films showed low moisture content (0.277 %), moderate WVP (31.278 g.mm/kPa.m2.h), low solubility (18.825 %), appropriate color parameters (Opacity: 12.411 AU.nm/mm, L*: 49.655, a*: 17.680, b*: 44.657), and balanced mechanical properties (TS: 13.270 MPa, EB: 20.638 %, and E: 64.592 MPa). These findings emphasize the potential of alginate films from Dictyota mertensii and promote sustainable use of marine resources.

A novel edible biocomposite coating based on alginate from the brown seaweed Dictyota mertensii loaded with beeswax nanoparticles extends the shelf life of yellow passion fruit

In this study, an edible biocomposite coating of alginate extracted from the brown seaweed Dictyota mertensii was loaded with beeswax nanoparticles (BDMAB) to extend the shelf life of yellow passion fruit (Passiflora edulis f. flavicarpa). The films were characterized by morphology, moisture content, contact angle, water vapor permeability, solubility, and optical and mechanical properties. Using a 4 × 6 factorial design, coated fruit was evaluated during six storage intervals (0, 2, 4, 6, 8, 10 days) at 22.5 ± 0.5 °C and 65 ± 5 % RH, focusing on respiration rate, weight loss, peel thickness and color, pulp yield and color, soluble solids, titratable acidity, ascorbic acid, phenolics, antioxidant capacity, and sensory acceptance. The BDMAB coating, composed of 67.9 % (w/w) ADM (bleached), 5 % (w/w) glycerol, 8.5 % (w/w) beeswax, and 18.6 % (w/w) Tween 80, significantly (p < 0.05) reduced the respiration rate, minimized weight loss, and preserved quality attributes, such as acidity, ascorbic acid, phenols, and antioxidant capacity. A 3-day extension in shelf life was inferred based on the climacteric peak delay of BDMAB-coated fruits compared with the control. Sensory analysis confirmed the acceptance of BDMAB coating. Therefore, BDMAB biocomposite coatings have great potential for preserving yellow passion fruit and promoting sustainability and conservation.

Development of a Multifunctional Chitosan-Based Composite Film from Crab Shell (Portunus segnis) and Algae (Ulva lactuca) with Enhanced Antioxidant and Antimicrobial Properties for Active Food Packaging

Eco-friendly, bioactive and edible films from renewable resources are increasingly regarded as viable replacements for petroleum-based packaging. This study investigates the application of Ulva lactuca macroalgae powder (ULP) as an active additive in crab (Portunus segnis) chitosan-based films for natural food packaging. Films with ULP concentrations of 0.5, 1.5, and 2.5% were prepared using a solvent-casting method with glycerol as a plasticizer. Their physicochemical, mechanical, functional, and biological properties were evaluated comprehensively. Fourier-transform infrared spectroscopy revealed intermolecular interactions between ULP's polyphenolic compounds and the chitosan matrix, enhancing the films' structural integrities. ULP's incorporation reduced the moisture content, water solubility, lightness (L*), redness (a*), and whiteness index values while significantly (p < 0.05) increasing the yellowness (b*), total color difference (ΔE), yellowness index (YI), tensile strength (TS), and elongation at break (EB). The antioxidant activity improved in a concentration-dependent manner, as evidenced by the high free-radical scavenging capacity. Moreover, antimicrobial tests showed significant inhibitory effects against pathogenic strains. Biodegradability tests confirmed that the films decomposed entirely within 12 days under soil burial conditions, reinforcing their environmental compatibility. These results highlight the multifunctional potential of chitosan-ULP composite films, combining enhanced mechanical properties, bioactivity, and sustainability. By utilizing renewable and biodegradable materials, this work contributes to reducing waste and promoting resource efficiency, aligning with the principles of a circular economy and environmental preservation.

Physicochemical characterization of bioactive polysaccharides from three seaweed and application of functional fruit packaging films

Seaweed polysaccharides show tremendous research and application value because of their significant and unique biological activities. However, reports on seaweed polysaccharides usually focus on in-depth studies of a specific biological activity, which severely limits their further development. Herein, three seaweed polysaccharides were isolated from Undaria pinnatifida (UPPS), Sargassum pallidum (SPPS), and Ulva lactuca (ULPS), respectively. The physicochemical properties, structure, rheological properties, antioxidant activities, antibacterial activities, and anti-glycation activities of UPPS, ULPS, and SPPS were comprehensively studied. It was first demonstrated that SPPS and UPPS had triple prominent biological activities. SPPS exhibited the best biological activities in antioxidation (IC50 in the ABTS test: 0.4616 ± 0.0134 mg/mL), antibacterial effect, and anti-glycation activity (inhibitory rate: 84.74 ± 0.07 %). Additionally, UPPS films (UPPSF) demonstrated superior ultraviolet shielding performance, lower water vapor permeability (1.78 ± 0.01 g/m·s·Pa × 10-11), higher hydrophobicity (water contact angle: 96.91 ± 2.52°), and higher antioxidant activity compared to ULPS films (ULPSF). UPPSF and ULPSF effectively prolonged the shelf life of strawberries to six days, and UPPSF showed better preservation properties. This work provides novel theoretical insights into the use of polysaccharides as medicinal nutraceuticals, bioactive agents, and food packaging films.

Value-added utilization technologies for seaweed processing waste in a circular economy: Developing a sustainable modern seaweed industry

The global seaweed industry annually consumes approximately 600,000 tons of dried algal biomass to produce algal hydrocolloids, yet only 15-30% of this biomass is utilized, with the remaining 70-85% discarded or released as scum or wastewater during the hydrocolloid extraction process. This residual biomass is often treated as waste and not considered for further commercial use, which contradicts the principles of sustainable development. In reality, the residual algal biomass could be employed to extract additional biochemical components, such as pigments, proteins, and cellulose, and these ingredients have important application prospects in the food sector. According to the biorefinery concept, recycling various products alongside the principal product enhances overall biomass utilization. Transitioning from traditional single-product processes to multi-product biorefineries, however, raises operating costs, presenting a significant challenge. Alternatively, developing value-added utilization technologies that target seaweed waste without altering existing processes is gaining traction among industry practitioners. Current advancements include methods such as separation and extraction of residual biomass, anaerobic digestion, thermochemical conversion, enzymatic treatment, functionalized modification of algal scum, and efficient utilization through metabolic engineering. These technologies hold promise for converting seaweed waste into alternative proteins, dietary supplements, and bioplastics for food packaging. Combining multiple technologies may offer the most effective strategy for future seaweed waste treatment. Nonetheless, most research on value-added waste utilization remains at the laboratory scale, necessitating further investigation at pilot and commercial scales.

Recovery and characterization of cellulose microfibers from fallen leaves and evaluation of their potential as reinforcement agents for production of new biodegradable packaging materials

In the present work, cellulose microfibers (CMFs) isolated from fallen autumn leaves of cherry plum (Prunus cerasifera pissardii nigra), white mulberry (Morus alba) and plane (Platanus orientalis) trees were characterized and used as reinforcement agents in sodium alginate-based biodegradable films. Fourier transform infrared spectroscopy (FT-IR) characterization showed that the CMFs were successfully isolated from the leaves with high purity. The extracted CMFs had a particle size ranging from 321.20 nm to 632.26 nm and negative zeta potential values (-27.33 to -21.40). The extraction yield of CMFs ranged from 19.53% to 26.00%. Incorporation of the leaf-derived CMFs into sodium alginate based films (1%, w:w) increased their tensile strength (from 153.73 to 187.78 MPa) and elongation at break values (from 105.97% to 89.90%) and significantly decreased oxygen (from 121.46 to 75.56 meq kg-1) and water vapor permeabilities (from 2.36 to 1.60 g mm h-1 m-2 kPa-1)(p < 0.05). Furthermore, the supplementation of CMFs into the biopolymer matrix had no significant effect on the color (L*: 85.35-85.67; a*: -0.75-0.71; b*: 4.23-4.94) and moisture content (44.64-48.42%) of the film samples, although the thickness increased (40.33-94.66 μm). Scanning electron microscopy (SEM) images showed that CMFs were homogeneously dispersed in the film matrix. Overall, this study confirms that fallen cherry plum, white mulberry, and plane leaves are valuable sources of CMFs which could be used in the manufacturing of biodegradable nanocomposite films as reinforcement agents.

Seaweed-based biopolymers for food packaging: A sustainable approach for a cleaner tomorrow

With the increasing environmental and health consequences of uncontrolled plastic use, the scientific community is progressively gravitating toward biodegradable and ecofriendly packaging alternatives. Seaweed polysaccharides have attracted attention recently because of their biodegradability, nontoxicity, antioxidant properties, and superior film-forming ability. However, it has some limitations for packaging applications, such as low tensile strength, water solubility, and only modest antimicrobial properties. The incorporation of biopolymers, nanoparticles, or organic active ingredients enhances these characteristics. This review encapsulates the contemporary research landscape pivoting around the role of seaweed polysaccharides in the development of bioplastics, active packaging solutions, edible films, and protective coatings. A meticulous collation of existing literature dissects the myriad food application avenues for these marine biopolymers, emphasizing their multifaceted physical, mechanical, thermal, and functional attributes, including antimicrobial and antioxidant. A key facet of this review spotlights environmental ramifications by focusing on their biodegradability, reinforcing their potential as a beacon of sustainable innovation. This article delves into the prevalent challenges that stymie large-scale adoption and commercialization of seaweed-centric packaging, offering a comprehensive perspective on this burgeoning domain.

Seaweed as Basis of Eco-Sustainable Plastic Materials: Focus on Alginate

Seaweed, a diverse and abundant marine resource, holds promise as a renewable feedstock for bioplastics due to its polysaccharide-rich composition. This review explores different methods for extracting and processing seaweed polysaccharides, focusing on the production of alginate plastic materials. Seaweed emerges as a promising solution, due to its abundance, minimal environmental impact, and diverse industrial applications, such as feed and food, plant and soil nutrition, nutraceutical hydrocolloids, personal care, and bioplastics. Various manufacturing techniques, such as solvent casting, injection moulding, and extrusion, are discussed for producing seaweed-based bioplastics. Alginate, obtained mainly from brown seaweed, is particularly known for its gel-forming properties and presents versatile applications in many sectors (food, pharmaceutical, agriculture). This review further examines the current state of the bioplastics market, highlighting the growing demand for sustainable alternatives to conventional plastics. The integration of seaweed-derived bioplastics into mainstream markets presents opportunities for reducing plastic pollution and promoting sustainability in material production.

Development of a Binderless Particleboard from Brown Seaweed Sargassum spp

Since 2010, huge quantities of Sargassum spp. algae have been proliferating in the Atlantic Ocean and stranding on Caribbean beaches, causing major economic, environmental, and health problems. In this study, an innovative high-density binderless particleboard was developed using uniaxial thermo-compression coupled with a cooling system. The raw material consisted of ground Sargassum seaweeds pre-treated by twin-screw extrusion with water to remove sea salt. The raw material and the particleboards were produced by using various analytical techniques such as Dynamic Vapor Sorption (DVS), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), or Thermogravimetric Analysis (TGA). The experimental conditions for thermo-compression (temperature, pressure, time) were evaluated. The best thermo-compression conditions tested were 200 °C, 40 MPa pressure for 7.5 min. This resulted in a particleboard with high density (up to 1.63 ± 0.02 g/cm3) and high flexural strength/modulus (up to 32.3 ± 1.8 MPa/6.8 ± 0.2 GPa, respectively), but a low water contact angle of 38.9° ± 3.5°. Thermal analyses revealed the effect of alginates on the mechanical properties of particleboards. This work opens the door to a new way of adding value to Sargassum seaweed, using the whole algae with minimal pre-treatment.

Development of seaweed-derived polysaccharide/cellulose nanocrystal-based antifogging labels loaded with alizarin for monitoring aquatic products' freshness

Intelligent freshness indicator labels have attracted great interest for their massive potential in monitoring the freshness of aquatic products over the years. However, there is still a challenge where fogging on the labels during dramatic temperature changes affects the reading of freshness. At the same time, the freshness indicator labels need high mechanical strength to resist collision damage during transportation and storage. Herein, an antifogging freshness indicator label was developed based on seaweed extracts and alizarin. Firstly, soluble polysaccharides and insoluble components were extracted from Gelidium amansii, and cellulose nanocrystal (CNC) was further prepared from the insoluble components by sulfuric acid hydrolysis. Subsequently, a polysaccharide-based film was fabricated using soluble polysaccharides as the matrix materials and CNC as the reinforcement agent. Antifogging experiments showed that the hydrophilic composite films presented good antifogging performance. After loading with alizarin, the composite indicator label exhibited both antifogging and freshness-indicating properties for the salmon sample. The work provided a new idea for developing freshness indicator labels suitable for low-temperature transportation and storage.

A novel high water-soluble antibacterial films-based guar gum incorporated with Aloe vera gel and ε-polylysine

The high water-soluble films are commonly used in food coating and food encapsulation. In this study, the effect of Aloe vera gel (AV) and ε-polylysine (ε-PL) on the comprehensive properties of films based on guar gum (GG) were investigated. When GG to AV was 8:2, the GG:AV:ε-PL composite films (water solubility = 68.50%) had an 82.42% higher water solubility than pure guar gum (PGG) films (water solubility = 37.55%). Compared with PGG films, the composite films more transparent, better thermal stability and elongation at break. X-ray diffraction and SEM analysis showed the composite films were amorphous structures and the AV and ε-PL did not change the structure of PGG. FITR analysis confirmed the formation of hydrogen bonds within the composite films. Antibacterial properties showed the composite films had a good antibacterial effect against Escherichia coli and Staphylococcus aureus. Therefore, the composite films can be a new option of high water-soluble antibacterial food packaging materials.

Preparation and Characterization of Novel Green Seaweed Films from Ulva rigida

Ulva rigida green seaweed is an abundant biomass consisting of polysaccharides and protein mixtures and a potential bioresource for bioplastic food packaging. This research prepared and characterized novel biodegradable films from Ulva rigida extracts. The water-soluble fraction of Ulva rigida was extracted and prepared into bioplastic films. 1H nuclear magnetic resonance indicated the presence of rhamnose, glucuronic and sulfate polysaccharides, while major amino acid components determined via high-performance liquid chromatography (HPLC) were aspartic acid, glutamic acid, alanine and glycine. Seaweed extracts were formulated with glycerol and triethyl citrate (20% and 30%) and prepared into films. Ulva rigida films showed non-homogeneous microstructures, as determined via scanning electron microscopy, due to immiscible crystalline component mixtures. X-ray diffraction also indicated modified crystalline morphology due to different plasticizers, while infrared spectra suggested interaction between plasticizers and Ulva rigida polymers via hydrogen bonding. The addition of glycerol decreased the glass transition temperature of the films from -36 °C for control films to -62 °C for films with 30% glycerol, indicating better plasticization. Water vapor and oxygen permeability were retained at up to 20% plasticizer content, and further addition of plasticizers increased the water permeability up to 6.5 g·mm/m2·day·KPa, while oxygen permeability decreased below 20 mL·mm/m2·day·atm when blending plasticizers at 30%. Adding glycerol efficiently improved tensile stress and strain by up to 4- and 3-fold, respectively. Glycerol-plasticized Ulva rigida extract films were produced as novel bio-based materials that supported sustainable food packaging.

Characterization of active Cerish fructan-sumac extract composite films: Physical, mechanical, and antioxidant properties

The biodegradable active films have the potential to increase the shelf life and safety of food products. In this study, the properties of Eremurus spectabilis (Cerish) root fructans (ESRF) film and its combination with Rhus coriaria L. (Sumac) extract (RCLE) at different concentrations (1%, 2%, 3%, and 4% w/w) were investigated. The Fourier transform infrared (FTIR) analysis determined the fingerprint region of fructans at 950-1150 cm^-1 in all spectrograms. RCLE increased the interactions between the hydroxyl groups and the formation of intermolecular bonds in composite films. Elongation-at-break (EAB) and tensile strength (TS) did not change significantly. However, RCLE increased Young's modulus (YM) (p ˂ .05), thermal stability, and crystallinity of composite films. RCLE also increased the film thickness and decreased the water content, solubility, and swelling degree significantly. RCLE improved the reducing ability and free radical-scavenging activity of composite films. Present results indicated that the ESRF/RCLE films were the protective barriers to the permeability of water vapor. The incorporation of RCLE increased the surface hydrophobicity and caused the composite film microstructure to become uniform and more compact. Overall, the Sumac extract at the specific concentration of 3% can be used to improve the Cerish fructans film properties and extend the product's shelf life in active food packaging.

Biomolecules from Macroalgae-Nutritional Profile and Bioactives for Novel Food Product Development

Seaweed is in the spotlight as a promising source of nutrition for humans as the search for sustainable food production systems continues. Seaweed has a well-documented rich nutritional profile containing compounds such as polyphenols, carotenoids and polysaccharides as well as proteins, fatty acids and minerals. Seaweed processing for the extraction of functional ingredients such as alginate, agar, and carrageenan is well-established. Novel pretreatments such as ultrasound assisted extraction or high-pressure processing can be incorporated to more efficiently extract these targeted ingredients. The scope of products that can be created using seaweed are wide ranging: from bread and noodles to yoghurt and milk and even as an ingredient to enhance the nutritional profile and stability of meat products. There are opportunities for food producers in this area to develop novel food products using seaweed. This review paper discusses the unique properties of seaweed as a food, the processes involved in seaweed aquaculture, and the products that can be developed from this marine biomass. Challenges facing the industry such as consumer hesitation around seaweed products, the safety of seaweed, and processing hurdles will also be discussed.

Coffee Waste Macro-Particle Enhancement in Biopolymer Materials for Edible Packaging

Plastic pollution has raised interest in biodegradable and sustainable plastic alternatives. For edible food packaging, seaweed biopolymers have been studied for their film-forming properties. In this study, packaging films were developed using the solvent casting technique from natural red seaweed (Kappaphycus alvarezii) and coffee waste product. The physico-chemical and thermal properties of seaweed/coffee biopolymer films was obtained using dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transmission irradiation (FT-IR), water contact angle measurement (WCA) and thermogravimetric analysis (TGA). The characterization study was carried out to improve the film's morphological, thermal, and mechanical properties. The average particle size of coffee waste was found to be between 1.106 and 1.281 µm, with a zeta potential value of -27.0 mV indicating the compound's strong negative charge. The SEM analysis revealed that the coffee filler was evenly dispersed in the polymer matrix, improving the film's structural properties. The FT-IR result shows that coffee waste was successfully incorporated over the film matrix with the presence of a N-H bond. The hydrophobic property of the film was enhanced with the incorporation of coffee filler, indicating increased water contact angle compared to the neat film. The tensile properties of the biopolymer film were significantly improved at 4 wt% coffee powder with optimum tensile strength (35.47 MPa) with the addition of coffee waste powder. The incorporation of coffee waste into the seaweed matrix increased the functional properties of the fabricated biopolymer film. Thus, seaweed/coffee biopolymer film has the potential to be used in food packaging and other applications.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

A Comparison of Cooking Conditions of Rhizoclonium Pulp as a Substitute for Wood Pulp

The green macroalga Rhizoclonium was cooked with 5%, 10%, and 20% sodium hydroxide (NaOH) for 4 h (5-N, 10-N, and 20-N groups, respectively); with 5%, 10%, and 20% sodium sulfite (Na2SO3) for 4 h (5-NS, 10-NS, and 20-NS groups, respectively); and with 5%, 10%, and 20% NaOH for 2 h and 1% hydrogen peroxide (H2O2) for 2 h (5-NH, 10-NH, and 20-NH groups, respectively). The 5-NH handsheet showed the best mechanical properties; however, the 10-NH pulp was easier to separate than 5-NH during handsheet making, and 10-NH was more suitable for the industrial process. Thus, the 10-NH group showed the optimal production conditions with an optimal length/width ratio, crystallinity index (CI%), three-dimensional (3D) configuration, and mechanical strength. Substituting 20% 10-NH Rhizoclonium pulp with wood pulp had no significant effect on the mechanical properties of the 100% wood pulp handsheet. However, the fibers of the NS group were flatter and lost their 3D configuration, resulting in low mechanical strength. Overall, Rhizoclonium had its own optimal cooking condition, which was not the same as for wood pulp, and it has potential as a substitute for wood pulp in papermaking.

Fucoidan from Marine Macroalgae: Biological Actions and Applications in Regenerative Medicine, Drug Delivery Systems and Food Industry

The marine macroalgae produce a collection of bioactive polysaccharides, of which the sulfated heteropolysaccharide fucoidan produced by brown algae of the class Phaeophyceae has received worldwide attention because of its particular biological actions that confer nutritional and health benefits to humans and animals. The biological actions of fucoidan are determined by their structure and chemical composition, which are largely influenced by the geographical location, harvest season, extraction process, etc. This review discusses the structure, chemical composition and physicochemical properties of fucoidan. The biological action of fucoidan and its applications for human health, tissue engineering, regenerative medicine and drug delivery are also addressed. The industrial scenario and prospects of research depicted would give an insight into developing fucoidan as a commercially viable and sustainable bioactive material in the nutritional and pharmacological sectors.

Antibacterial Gelidium amansii polysaccharide-based edible films containing cyclic adenosine monophosphate for bioactive packaging

A homogeneous polysaccharide (GAP), with a molecular weight of 51.8 kDa, was isolated from edible red seaweed Gelidium amansii. Composition analysis suggested GAP contained 5.31% sulfate and 17.33% 3,6-anhydro-galactose and was mainly composed of galactose. Furthermore, GAP, as a biopolymer matrix, was used to form the composite films with the small biological molecules cytidine-5'-monophosphate (CMP), adenosine-5'-monophosphate (AMP), and cyclic adenosine monophosphate (cAMP). Scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrum, and X-ray diffraction (XRD) results showed that CMP, AMP, and cAMP interacted with the film substrates and might made films more complex. Notably, the addition of CMP, AMP, and cAMP promoted the light, water vapor, and oxygen barrier ability, surface wettability, mechanical strength, and antimicrobial activity against Gram-negative and -positive bacteria. Finally, GAP-based films composited with cAMP (cAMPF) exhibited the best characteristics were applied to fish packaging and preservation at 4 °C and extended the fish shelf life. All these data suggested the potential value of cAMPF as a functional edible polysaccharide film applied in food industries.

An Overview of the Alternative Use of Seaweeds to Produce Safe and Sustainable Bio-Packaging

In modern times, seaweeds have become widely involved in several biotechnological applications due to the variety of their constituent bioactive compounds. The consumption of seaweeds dates to ancient times; however, only from the last few decades of research can we explain the mechanisms of action and the potential of seaweed-derived bioactive compounds, which has led to their involvement in food, cosmetic, pharmaceutical, and nutraceutical industries. Macroalgae-derived bioactive compounds are of great importance as their properties enable them to be ideal candidates for the production of sustainable “green” packaging. Diverse studies demonstrate that seaweed polysaccharides (e.g., alginates and carrageenans) not only provide health benefits, but also contribute to the production of biopolymeric film and biodegradable packaging. The dispersion of plastics and microplastics in the oceans provoke serious environmental issues that influence ecosystems and aquatic organisms. Thus, the sustainable use of seaweed-derived biopolymers is now crucial to replace plasticizers with biodegradable materials, and thus preserve the environment. The present review aims to provide an overview on the potential of seaweeds in the production of bioplastics which might be involved in food or pharmaceutical packaging.

Recent advancement in improvement of properties of polysaccharides and proteins based packaging film with added nanoparticles: A review

Innovations and research on packaging materials are in a fast-growing stage to make them suitable for advanced packaging innovations and sustainability efforts. Biological macromolecules like algal polysaccharides, chitosan, gelatin and others like starch are explored for developing eco-friendly packaging alternatives. Compared to conventional synthetic polymers they have performance limitations that are tried to be overcome with added fillers. The unique properties of fillers in the nano range are explored for this. They can improve the overall property of polymer matrixes by improving barrier properties to oxygen and water vapour, increasing stability and mechanical strength. Exploring the possibilities of new nanoparticle-polymer combinations can bring novel properties in the packaging industry that can be used in smart and intelligent packaging areas. Thus studies on nanocomposite films from polysaccharides, protein compounds and nanoparticles can help to overcome the limitations of bio-polymers for novel packaging applications. This review covers the effect of nanoparticles on the optical, morphological, barrier, thermal and mechanical properties of polysaccharides and proteins based packaging film, along with the types of nanoparticles used in the composite films.

Algae application in civil construction: A review with focus on the potential uses of the pelagic Sargassum spp. biomass

Pelagic Sargassum, usually found at the Sargasso Sea and the Western portion of the North Atlantic and Gulf of Mexico, has been detected in many new locations through the tropical Atlantic. The huge biomass found from the African coast to the Caribbean was called the Great Atlantic Sargassum Belt and is responsible for the stranding of tons of algae on coastal regions. Despite the environmental, social, and economic impacts, sargassum is a valuable source for multiple uses at the industry, such as alginates, cosmetics, recycled paper and bioplastics, fertilizers, and as raw material for civil construction. This work presents a systematic literature review on the use of algae at the civil construction sector, with a focus on the valorization of the pelagic Sargassum spp. biomass, by identifying the potential applications related to the use of other algal species. The review considered other genera of marine algae and marine angiosperms, resulting in a total of 31 selected articles. The marine grass Posidonia oceanica was the most used species, found in eight published papers, followed by the red alga Kappaphycus alvarezii with four studies. Two articles were available on the use of pelagic Sargassum spp. (S. fluitans and S.natans) for construction materials (adobe and pavement), with potential good results. The literature presented results from the use of marine algae and sea grasses for particleboards, polymeric and cemented composites, adobe, pavement, facades, and roofs. This article provides a state-of-the-art review of algal application in the civil construction sector and points out the main directions for the potentialities on the insertion of the Sargassum spp. biomass into the production chain of the sector.

Seaweed-based cellulose: Applications, and future perspectives

Cellulose is a naturally occurring organic polymer extracted mainly from lignocellulosic biomass of terrestrial origin. However, the increasing production of seaweeds for growing global market demands has developed the opportunity to use it as an additional cellulose source. This review aims to prepare comprehensive information to understand seaweed cellulose and its possible applications better. This is the first review that summarizes and discusses the cellulose from all three types (green, red, and brown) of seaweeds in various aspects such as contents, extraction strategies, and cellulose-based products. The seaweed cellulose applications and future perspectives are also discussed. Several seaweed species were found to have significant cellulose content (9-34% dry weight). The review highlights that the properties of seaweed cellulose-based products were comparable to products prepared from plant-based cellulose. Overall, this work demonstrates that cellulose could be economically extracted from phycocolloids industrial waste and selected cellulose-rich seaweed species for various commercial applications.

Preparation and characterization of chitosan-based edible active films incorporated with Sargassum pallidum polysaccharides by ultrasound treatment

In this study, Sargassum pallidum polysaccharides (SPPs) were incorporated into chitosan (CH) to develop a novel edible active film (CH/SPPs-US) via ultrasonication. The mechanical, water vapor permeability, surface morphology, crystallinity, antioxidant, and fruit preservation properties of CH/SPPs-US films prepared under sequences of matrix ratios and ultrasound treatment were investigated. The results revealed that the addition of SPPs combined with ultrasonic treatment could significantly enhance the transparency, elongation and tensile strength of the films whereas the water vapor permeability was decreased. Tensile strength and elongation at break of the C2/SP1.2-US film were 12.07 N and 54.18%, respectively, which were significantly higher than those for CH film. Meanwhile, the water vapor permeability value of C2/SP1.2-US was reduced by as high as 40.2% compared with that of chitosan film. In addition, antioxidant effect evaluation showed that the CH-based films added with SPPs exhibited better antioxidant activity than CH film, and ultrasonic treatment could further strengthen the antioxidant activity of the film. The CH/SPPs-US films could effectively extend the shelf life and inhibit the deterioration of the strawberry at room temperature (25 ± 1 °C) and 70% ± 5% relative humidity for 7 days. These results indicated that the CH/SPPs edible films via ultrasonication could be developed as edible packaging films for the preservation of fresh fruits.

Evaluation of Chemical, Functional, Spectral, and Thermal Characteristics of Sargassum wightii and Ulva rigida from Indian Coast

Usage of seaweeds as a functional food/food ingredient is very limited due to paucity of scientific information about variations in the nutritional composition of seaweeds under diverse climatic conditions. Sargassum wightii and Ulva rigida seaweeds are found abundantly on the Southern Indian coastline and were thoroughly evaluated in this work. Crude fiber and lipid of S. wightii were higher (24.93 ± 0.23% and 3.09 ± 0.41%, respectively) as compared to U. rigida; however, U. rigida had higher crude protein content (27.11 ± 0.62%). Evaluation of mineral and CHNS content indicated that the concentration of potassium, magnesium, and calcium was 1.36 ± 0.08 mg/g, 8.39 ± 0.80 mg/g, and 14.03 ± 3.46 mg/g, respectively, that was higher in the S. wightii, whereas U. rigida contained higher value of iron, carbon, and sulphur (0.70 ± 0.13 mg/g, 37.72 ± 4.63%, and 2.61 ± 0.16%, respectively). Swelling capacity (19.42 ± 0.00 mL/g DW to 22.66 ± 00 mL/g DW), water-holding capacity (6.15 ± 0.08 g/g DW to 6.38 ± 0.14 g/g DW), and oil-holding capacity (2.96 ± 0.13 g/g DW) of U. rigida were significantly ( $p<0.05$ ) higher as compared to S. wightii. It was observed from DSC thermograms that S. wightii can be safely processed for food formulations even at a temperature of 134°C. The thermograms also revealed changes in the sulphated polysaccharide (fucoidan) profile due to the presence of hydroxyl and carboxyl groups with denaturation of proteins. TGA of S. wightii and U. rigida showed degradation temperature within the range of 200–300°C due to divergent polysaccharide compositions. FTIR spectroscopy suggested the presence of phenolic groups in both seaweeds (at 1219 cm−1). Results of the study suggested that the manufacturing of functional food products from seaweeds could be beneficial and may aid in social upliftment of cultivators/fishermen.

Functional Properties of Antimicrobial Neem Leaves Extract Based Macroalgae Biofilms for Potential Use as Active Dry Packaging Applications

Antimicrobial irradiated seaweed–neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves’ extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed–neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem–seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed–neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.

P. S. AK, Olaiya NG, Abdullah CK, Alfatah T, Gopakumar DA, Pasquini D. Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

Carboxymethyl chitosan-pullulan edible films enriched with galangal essential oil: Characterization and application in mango preservation

This study aimed to develop an active edible film based on carboxymethyl chitosan (CMCS) and pullulan (Pul) incorporated with galangal essential oil (GEO) by the casting method. And their physical properties, structural and preservation effect on mangoes were characterized. The CMCS/Pul ratio was determined to be 2.5:2.5 after the optimization of physical properties, mechanical properties and barrier properties of the blend film. The results of FT-IR and XRD showed that hydroxyl groups of Pul interacted with the carboxyl groups of CMCS and the blend films had good compatibility. Good thermal stability of CMCS/Pul-GEO films was further proven by TGA curves. The CMCS/Pul-8 %GEO film showed effective preservations on mango fruits during 15 days of storage at 25 ± 1 °C, based on the characterization by fruits weight loss, firmness, titratable acidity, soluble solids. Consequently, CMCS/Pul-GEO blend films may be a promising eco-friendly packaging material for the industrial application of fruit preservation.

Antibacterial Use of Macroalgae Compounds against Foodborne Pathogens

The search for food resources is a constant in human history. Nowadays, the search for natural and safe food supplies is of foremost importance. Accordingly, there is a renewed interest in eco-friendly and natural products for substitution of synthetic additives. In addition, microbial contamination of food products during their obtaining and distribution processes is still a sanitary issue, and an important target for the food industry is to avoid food contamination and its related foodborne illnesses. These diseases are fundamentally caused by certain microorganisms listed in this review and classified according to their Gram negative or positive character. Algae have proven to possess high nutritional value and a wide variety of biological properties due to their content in active compounds. Among these capabilities, macroalgae are recognized for having antimicrobial properties. Thus, the present paper revises the actual knowledge of microbial contaminants in the food industry and proposes antimicrobial algal compounds against those pathogenic bacteria responsible for food contamination as valuable molecules for its growth inhibition. The capacity of algae extracts to inhibit some major food pathogen growth was assessed. Moreover, the main applications of these compounds in the food industry were discussed while considering their favorable effects in terms of food safety and quality control.