Biodegradable films from soyhull cellulosic residue with UV protection and antioxidant properties improve the shelf-life of post-harvested raspberries

Post-harvest loss of fruits and vegetables, and health risks and environmental impact of current plastic packaging warrant new biodegradable packaging. To this end, cellulosic residue from agricultural processing byproducts is suitable due to its renewability and sustainability. Herein, soyhulls cellulosic residue was extracted, solubilized in ZnCl2 solution, and crosslinked with calcium ions and glycerol to prepare biodegradable films. The film combination was optimized using Box Behnken Design and film properties were characterized. The optimized film is translucent and exhibits tensile strength, elongation at break, water vapor permeability, hydrophobicity, and IC50 of 6.3 ± 0.6 MPa, 30.2 ± 0.9%, 0.9 ± 0.3 × 10-10 gm-1 s-1 Pa-1, 72.6°, and 0.11 ± 0.1 g/mL, respectively. The water absorption kinetics follow the Peleg model and biodegrade within 25 days at 24% soil moisture. The film extends the shelf life of raspberries by 6 more days compared to polystyrene film. Overall, the value-added soyhull cellulosic films are advantageous in minimizing post-harvest loss and plastic-related issues, emphasizing the principles of the circular bioeconomy.

Functional characterization of biodegradable films obtained from whole Paecilomyces variotii biomass

The indiscriminate use of petroleum-based polymers and plastics for single-use food packaging has led to serious environmental problems due the non-biodegradable characteristics. Thus, much attention has been focused on the research of new biobased and biodegradable materials. Yeast and fungal biomass are low-cost and abundant sources of biopolymers with highly promising properties for the development of biodegradable materials. This study aimed to select a preparation method to develop new biodegradable films using the whole biomass of Paecilomyces variotii subjected to successive physical treatments including ultrasonic homogenization (US) and heat treatment. Sterilization process had an important impact on the final filmogenic dispersion and mechanical properties of the films. Longer US treatments produced a reduction in the particle size and the application of an intermediate UT treatment contributed favorably to the breaking of agglomerates allowing the second US treatment to be more effective, achieving an ordered network with a more uniform distribution. Samples that were not filtrated after the sterilization process presented mechanical properties similar to plasticized materials. On the other hand, the filtration process after sterilization eliminated soluble and hydratable compounds, which produced a reduction in the hydration of the films.

Influence of Glycerol on the Surface Morphology and Crystallinity of Polyvinyl Alcohol Films

The structure and physicochemical properties of polyvinyl alcohol (PVA) and PVA/glycerol films have been investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA), and advanced scanning probe microscopy (SPM). In the pure PVA films, SPM allowed us to observe ribbon-shaped domains with a different frictional and elastic contrast, which apparently originated from a correlated growth or assembly of PVA crystalline nuclei located within individual PVA clusters. The incorporation of 22% w/w glycerol led to modification in shape of those domains from ribbon-like in pure PVA to rounded in PVA/glycerol 22% w/w films; changes in the relative intensities of the XRD peaks and a decrease in the amorphous halo in the XRD pattern were also detected, while the DTA peak corresponding to the melting point remained at almost the same temperature. For higher glycerol content, FT-IR revealed additional glycerol-characteristic peaks presumably related to the formation of glycerol aggregates, and XRD, FT-IR, and DTA all indicated a reduction in crystallinity. For more than 36% w/w glycerol, the plasticization of the films complicated the acquisition of SPM images without tip-induced surface modification. Our study contributes to the understanding of crystallinity in PVA and how it is altered by a plasticizer such as glycerol.

A comparative study of the effects of graphite, wollastonite, and titanium dioxide fillers on the properties of starch-based biodegradable plastic film

This research paper aims to explore the effect of graphite, wollastonite, and titanium dioxide as reinforcing fillers on starch-based biodegradable plastic (SBP) films. GF-SBP (graphite filler containing SBP), WF-SBP (wollastonite containing SBP), and TF-SBP (titanium dioxide containing SBP) films were developed and analyzed for various properties such as thickness, density, tensile strength, elongation break, morphology, thermal stability, solubility, moisture content, moisture absorbance, biodegradability, and antibacterial activity. The results reveal that WF-SBP films had the highest tensile strength of 5.43 MPa and greatest elongation break value of 22% as compared to other films. Thermogravimetric analysis showed that SBP films with and without filler degraded slowly between 150 and 600°C. The highest thermal stability was recorded for TF-SBP films which showed stability (11% mass loss) up to 150°C. The biodegradability test conducted using soil burial method suggested that TF-SBP film degraded within 90 days, GF-SBP films degraded completely in 120 days, and WF-SBP films took more than 120 days to degrade. The synthesized SBP films were analyzed for their antibacterial potential against gram-positive and gram-negative bacteria, and results showed that WF-SBP film exhibited the best antibacterial activity by producing a large zone of inhibition against Escherichia coli.

The physicochemical properties and molecular docking study of plasticized amphotericin B loaded sodium alginate, carboxymethyl cellulose, and gelatin-based films

Plasticizers are employed to stabilize films by safeguarding their physical stability and avoiding the degradation of the loaded therapeutic drug during processing and storage. In the present study, the plasticizer effect (glycerol) was studied on bioadhesive films based on sodium alginate (SA), carboxymethyl cellulose (CMC) and gelatin (GE) polymers loaded with amphotericin B (AmB). The main objective of the current study was to assess the morphological, mechanical, thermal, optical, and barrier properties of the films as a function of glycerol (Gly) concentration (0.5-1.5 %) using different techniques such as Scanning Electron Microscope (SEM), Texture analyzer (TA), Differential Scanning Calorimeter (DSC), X-Ray Diffraction (XRD), and Fourier Transforms Infrared Spectroscopy (FTIR). The concentration increase of glycerol resulted in an increase in Water Vapor Permeability (WVP) (0.187-0.334), elongation at break (EAB) (0.88-35.48 %), thickness (0.032-0.065 mm) and moisture level (17.5-41.76 %) whereas opacity, tensile strength (TS) (16.81-0.86 MPa), and young's modulus (YM) (0.194-0.002 MPa) values decreased. Glycerol incorporation in the film-Forming solution decreased the brittleness and fragility of the films. Fourier Transform Infrared (FTIR) spectra showed that intermolecular hydrogen bonding occurred between glycerol and polymers in plasticized films compared to control films. Furthermore, molecular docking was applied to predict the binding interactions betweem AmB, CMC, gelatin, SA and glycerol, which further endorsed the stabilizing effects of glycerol in the complex formation between AmB, CMC, SA, and gelatin. The Findings of the current study demonstrated that this polymeric blend could be used to successfully prepare bioadhesive films with glycerol as a plasticizer.

Green interconnected network structure of chitosan-microcrystalline cellulose-lignin biopolymer film for active packaging applications

As an excellent alternative to petroleum-based food packaging materials, a novel green hybrid composite film with an excellent interconnected network structure was successfully fabricated by integrating chitosan (chi), microcrystalline cellulose (MCC), and lignin nanoparticles (LNP), including the desired amount of plasticizer glycerol (gly). Overall, 36 combinations were developed and investigated for superior biocomposite film formation. Among the various concentration ratios, the 40:35:25 chi-MCC-gly film provided well-organized film formation, good physicochemical properties, mechanical stability, efficient water contact angle, reduced water solubility, and lower water vapor permeability (11.43 ± 0.55 × 10-11 g.m-1.s-1.Pa-1). The performance of the chi-MCC-gly film further enhanced by the homogeneous incorporation of ∼100 nm LNP. With 1 % LNP addition, the tensile strength of the film increased (28.09 MPa, 47.10 % increase) and the water vapor permeability reached a minimum of 11.43 × 10-11 g.m-1.s-1.Pa-1, which proved the impact of LNP in composite films. Moreover, the films showed excellent resistance to thermal shrinkage even at 100 °C and exhibited nearly 100 % UV blocking efficiency at higher LNP concentrations. Interestingly, the green composite films extended the shelf life of freshly cut cherry tomatoes to seven days without spoilage. Overall, the facile synthesis of strong, insoluble, UV-blocking, and thermally stable green composite films realized for food packaging applications.

Optimization and characterization of taro starch, nisin, and sodium alginate-based biodegradable films: antimicrobial effect in chicken meat

Biodegradable films based on polymers from renewable resources have become a feasible technology to preserve the quality (texture, color, flavor) and safety of food. The addition of antimicrobial agents to films can prevent the growth of pathogenic microorganisms that affect meat and poultry products. In this study, a biodegradable film with sodium alginate (SA), taro starch (MS), and nisin (Nis) was optimized to have high tensile strength (TS), breaking force (BF), and a low water vapor permeability (WVP) using a Box-Behnken response surface design, and its antimicrobial effect was evaluated in relation to its use as a packaging material for chicken meat. The OB was characterized via analysis of its mechanical, physical, and chemical properties; in addition, the total migration of Nis was also analyzed, along with its retention ability, the kinetics of the release of Nis into food simulants, and its antimicrobial activity against Listeria monocytogenes in vitro and on inoculated chicken meat. The resulting optimal OB was produced with 1.9% MS, 1% glycerol (G), and 2,369 IU/mL of Nis, and displayed adequate TS and WVP. The OB significantly reduced the microbial load and helped extend the shelf life of the chicken meat under refrigeration by up to 15 d. Total migration and the kinetics of the release of Nis showed that the OB can be used on hydrophilic and acidic foods, making it a natural alternative for use in food packaging.

Effects of polyols with different hydroxyl numbers on the structure and properties of starch straws

To study the relationship between the number of hydroxyl groups of polyols and the plasticizing effect, the effects of different polyols including ethylene glycol, glycerol, erythritol, xylitol and sorbitol on the structure and properties of corn starch straws were analyzed and compared. The results showed that the addition of plasticizer significantly improved the performance of starch straws, which greatly improved the mechanical properties, water absorption rate (WAR) and thermal stability. However, there was no linear relationship between the plasticizing effect on starch straws and the number of hydroxyl groups in plasticizers. Fourier transform infrared (FTIR) results showed that erythritol formed the strongest intermolecular interaction with starch. Starch straws with erythritol (S-ERY) had the highest bending force (Fb = 25.78 N) and the lowest WAR. Starch straws with glycerol (S-GLY) showed the lowest relative crystallinity (RC = 12.87 %) and the highest temperature of the maximum degradation (Tdmax = 302.1 °C). In addition, after storing for 180 days, S-GLY showed higher modulus of elasticity in bending (Eb = 4.26 N/cm) and a uniform surface.

Preparation of Surgical Thread from a Bioplastic Based on Nopal Mucilage

Currently, natural materials represent a sustainable option for the manufacture of biopolymers with numerous industrial applications and characteristics comparable with synthetic materials. Nopal mucilage (NM) is an excellent natural resource for the synthesis of bioplastics (BPs). In the present research, the fabrication of biopolymers by using NM is addressed. Changes in the plasticizer (sorbitol and cellulose) concentration, in addition to the implementation of two sources of starch (corn starch (CS) and potato starch (PS)) to obtain the surgical thread, were analyzed. The NM extracted was close to 14% with ethanol. During the characterization of the extract, properties such as moisture, humidity, viscosity, and functional groups, among others, were determined. In the CS and PS analysis, different structures of the polymeric chains were observed. BP degradation with different solvents was performed. Additionally, the addition of sorbitol and cellulose for the BP mixtures presenting the highest resistance to solvent degradation and less solubility to water was conducted. The obtained thread had a uniform diameter, good elasticity, and low capillarity compared to other prototypes reported in the literature.

Influence of Pomelo (Citrus maxima) Pericarp Essential Oil on the Physicochemical Properties of HomChaiya Rice (Oryza sativa L. cv. HomChaiya) Flour-Derived Edible Films

The food industry is increasingly interested in using active edible packaging to address environmental problems caused by conventional synthetic polymers, such as pollution and degradation. The present study took advantage of this opportunity to develop active edible packaging using Hom-Chaiya rice flour (RF), incorporating pomelo pericarp essential oil (PEO) at varying concentrations (1-3%). Films without PEO were used as controls. Various physicochemical parameters, structural and morphological observations were examined in the tested films. Overall, the results showed that the addition of PEO at varying concentrations significantly improved the qualities of the RF edible films, particularly the film's yellowness (b*) and total color. Furthermore, RF-PEO films with increased concentrations significantly reduced the film's roughness and relative crystallinity, while increasing opacity. The total moisture content in the films did not differ, but water activity was significantly reduced in the RF-PEO films. Water vapor barrier properties also improved in the RF-PEO films. In addition, textural properties, including tensile strength and elongation at break, were better in the RF-PEO films compared with the control. Fourier-transform infrared spectroscopy (FTIR) revealed strong bonding between the PEO and RF in the film. Morphological studies showed that the addition of PEO smoothed the film's surface, and this effect increased with concentration. Overall, the biodegradability of the tested films was effective, despite variations; however, a slight advancement in degradation was found in the control film. Lastly, the antimicrobial properties of the RF-PEO films exhibited excellent inhibitory effects against various pathogens, including Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), and Salmonella typhimurium (S. typhimurium). This study demonstrated that RF and PEO could be an effective combination for developing active edible packaging that delivers desirable functional properties and excellent biodegradability.

The physiochemical and photodynamic inactivation properties of corn starch/erythrosine B composite film and its application on pork preservation

This study explored the effect of erythrosine B (EB) as a photosensitizer in corn starch (CS) film and its physicochemical properties and photodynamic bacteriostatic ability against Staphylococcus aureus, Escherichia coli, and Salmonella both in vitro and inoculated on pork under the irradiation of D65 light-emitting diode (LED) (400-800 nm). The study revealed that the physiochemical properties of CS films: moisture content, water solubility, and water vapor transmission were improved with the addition of EB. In addition, the elasticity and the thermal stability of the film were enhanced. The results showed that the CS-EB films stimulated a maximum of 26.36 μg/mL hydrogen peroxide and 74.5 μg/g hydroxyl radical under irradiation. The CS composite films with a 5 % concentration of EB inhibited the bacterial growth by 4.7 Log CFU/mL in vitro after 30 min of illumination, and 2.4 Log CFU/mL on the pork samples under the same experimental condition. Moreover, the antibacterial ability was enhanced with the increase in EB concentration. Overall, the CS-EB composite films can inhibit the growth of bacteria through photodynamic inactivation and has the potential to become a new type of environmentally friendly packaging material.

Effect of Various Plasticizers in Different Concentrations on Physical, Thermal, Mechanical, and Structural Properties of Wheat Starch-Based Films

Biocomposite materials are essential for environmental protection, as they have the ability of substituting synthetic plastic with natural materials. This work investigated how different plasticizers (Glycerol (G), Fructose (F), Sorbitol (S), and Urea (U)) affect the morphological, mechanical, thermal, and physical characteristics of films made of wheat starch at various concentrations (0%, 15%, 25%, and 35%). Plasticizers were added to improve the flexibility and homogeneity of the wheat starch-based bioplastic. Control film exhibited high tensile strength (38.7 MPa) with low elongation (1.9%). However, films plasticized with 35% sorbitol showed the highest elongation, which was 60.7% at break. At 35% of all plasticizers, fructose showed the highest tensile strength, with 7.6 MPa. The addition of different plasticizers shows improvement in water resistance; films plasticized with glycerol had the lowest water absorption at 35% fructose (187.4%) and also showed coherent surfaces. Glycerol, sorbitol, and urea films showed a higher mass loss compared to fructose films. Fructose showed the highest performance after the analysis of the results, with low water absorption, water content, and mass loss and with high mechanical performance at 35% of fructose. SEM images show that the addition of fructose and glycerol improves the surface homogenate, while sorbitol and urea have a less compact structure with large pores.

Obtention of New Edible Biofilms from Water Kefir Grains in Comparison with Conventional Biofilms from Taro (Colocasia esculenta) and Cassava (Manihot esculenta) Starch

Microorganism biomass is a sustainable and innovative source of biopolymers, such as proteins and polysaccharides, that is suitable for the development of biodegradable films. The aim of this research was to evaluate the synthesis, morphology, rheology, and morphological and mechanical properties on the production of edible biofilms based on water kefir grains, and compare them with edible films based on thermoplastic compounds from starch (TPS) obtained from taro (Colocasia esculenta) and cassava (Manihot esculenta). Edible biofilms were prepared in solution with 30% wt/wt glycerol relative to starch mass and kefir grain biofilms using the casting method. A stationary rheological analysis was performed on the film-forming suspensions of kefir, taro starch, and cassava starch. Once the films were obtained, a physicochemical and morphological characterization was carried out. Results of the characterization showed the following main aspects: The results indicated an increase in biomass production using muscovado and pineapple peel. The film-forming suspensions had a dilating behavior; however, the results obtained not only show the viscoelastic behavior but also the elastic limit (σ0), which varied from 0.077 to 0.059 Pa for suspensions of water kefir grains and from 0.077 to 0.072 Pa for starch suspensions. These elastic limit variations can be defined as the minimum shear stress required to start the flow, and all these rheological data were adjusted to the Herschel–Bulkley model; the morphological and mechanical characterization of the films obtained showed homogeneous surfaces with transparency and without cracks; regarding the water activity, values lower than 6 were obtained, which indicates that there will be no growth of any microorganism, and the hardness data showed differences between those obtained from kefir and taro and cassava starch. The similar results of the rheological characterization in the formation of the kefir biofilm and the conventional edible starch films, in addition to the similar results in the water activity below 6 and the hardness, points to an attractive alternative capable of replacing the conventional materials with a mass production of biofilms of probiotic microorganisms. The results also revealed that water kefir grains biomass is a viable and innovative source of biodegradable materials, and these grains can be an alternative to conventional established starch materials.

Preparation of the alginate/carrageenan/shellac films reinforced with cellulose nanocrystals obtained from enteromorpha for food packaging

Enteromorpha prolifera belonging to the chlorophyta phylum is the main pollutant of "green tide", and propagates rapidly in recent years. However, there is almost no high-value enteromorpha treatment method at present. This study aimed to extract cellulose nanocrystals (CNC) from enteromorpha and prepare the CNC reinforced films based on alginate, carrageenan and shellac for food packaging. The effects of alginate, κ-carrageenan, cellulose nanocrystals and glycerin on the CNC reinforced alginate/carrageenan films (AC films) properties were studied systematically in this work. The results showed that the mechanical properties, swelling properties, and barrier properties of the AC could be adjusted by the concentrations of the different components. In addition, response surface methodology (RSM) was used to optimize the formula of the AC used for food packaging according to the requirements of the practical application. Furthermore, in order to further improve the food packaging capacity of the composite films, shellac was added to the optimized alginate/carrageenan films (OAC films) to obtain the shellac optimized alginate/carrageenan films (SOAC films). Finally, the OAC films and SOAC films showed excellent properties to extend the storage time of chicken breast and cherry tomatoes in the food storage experiment.

Novel Karaya Gum Derivatives Produced by Alkaline Hydrolysis and Periodate Oxidation for Active Packaging with Cinnamaldehyde

This study aims to produce novel derivatives of karaya gum using chemical modification and then apply them for active packaging with cinnamaldehyde as the main active component. Native karaya gum (NKG) was hydrolyzed using sodium hydroxide to yield hydrolyzed karaya gum (HKG), which then was oxidized using sodium periodate to yield hydrolyzed-oxidized karaya gum (HOKG). For comparison, NKG was also directly oxidized using sodium periodate to produce oxidized karaya gum (OKG). FTIR spectra confirmed the removal of acetyl groups after alkaline hydrolysis and the formation of carbonyl groups with subsequent formation of hemiacetal and acetal structures after periodate oxidation. The alkaline hydrolysis and the periodate oxidation resulted in opposite effects on the hydrophilicity of the gum: hydrolysis increased solubility, moisture uptake, and viscosity, while periodate oxidation decreased these properties. We then produced films from corn starch and these gums (5% $w/w$ gum/starch) and properties of the films were studied. Hydrolysis of KG resulted in higher tensile strength, higher transparency but lower puncture strength and antifungal activity against of the films, while periodate oxidation exerted the opposite effects. The incorporation of 5% cinnamaldehyde ( $w/w$ of starch) exerted strong antifungal and antibacterial effects on the films against Colletotrichum gloeosporioides and Escherichia coli, which are useful in active packaging. The active packages based on the novel derivatives of KG can find applications in the agricultural, food, and pharmaceutical industries.

Modulation of interfacial interactions toward strong and tough cellulose nanofiber-based transparent thin films with antifogging feature

Cross-linking is often performed to overcome the weak mechanical properties of native polymer films in order to expand their functional properties and applications. While this approach offers enhanced strength to the film, the film also suffers from low flexibility, low toughness and high brittleness. However, in view of the growing demand for strong and tough transparent thin films, this article reported our study to develop films made from cellulose nanofiber (CNF) via tailoring the interfacial bonding interactions through the application of glycerol (Gly) and glutaraldehyde (GA), which functioned as a plasticizer and cross-linking agent, respectively. Among the prepared films, the 10GA-8Gly-CNF film exhibited the best results with regard to the enhancement in the tensile strength (21.1%), Young's modulus (10.6%), elongation at break (100%) and toughness (32.7%), as compared to the native CNF film. Importantly, treating the surface of the film to radiofrequency oxygen plasma endowed the film with antifogging property, without compromising the optical clarity.

Xanthan-gelatin and xanthan-gelatin-keratin wound dressings for local delivery of Vitamin C

Recently, functional dressings that can protect the wound area from dehydration and bacterial infection and support healing have gained importance in place of passive dressings. This study aimed to develop temporary and regenerative xanthan/gelatin (XGH) and keratin/xanthan/gelatin hydrogels (KXGHs) that have high absorption capacity and applicability as a wound dressing that can provide local delivery of Vitamin C (VC). Firstly, xanthan/gelatin hydrogels were produced by crosslinking with different glycerol concentrations and characterized to determine the hydrogel composition. According to their weight ratios, xanthan, gelatin, and glycerol hydrogels are named. If their weight ratio is 1:1:2 (w/w/w), the group name is selected as X1:GEL1:GLY2. X1:GEL1:GLY2 hydrogel was selected for biocompatibility, mechanical property, water vapor transmission rate (WVTR), and porosity. The addition of keratin to X1:GEL1:GLY2 improved L929 fibroblasts viability and increased protein release. Water vapor transmission of XGHs and KXGHs was between 3059.09 ± 126 and 4523 ± 133 g m^-2 d^-1; therefore, they can be suitable for granulating, low to moderate exudate wounds. XGH and KXGHs loaded with VC had higher water uptake, making it more convenient for exudate wounds. VC was released for 100 h, and VC containing XGHs and KXGHs increased the collagen synthesis of L929 fibroblasts. All of the hydrogels (XGH, KXGH, and VC-KXGHs) inhibited the bacteria transmission. In conclusion, our results suggest that VC-XGH and VC-KXGH can be candidates for temporary wound dressing materials for skin wounds.

Natural Polymers Used in Edible Food Packaging—History, Function and Application Trends as a Sustainable Alternative to Synthetic Plastic

In this review, a historical perspective, functional and application trends of natural polymers used to the development of edible food packaging were presented and discussed. Polysaccharides and proteins, i.e., alginate; carrageenan; chitosan; starch; pea protein, were considered. These natural polymers are important materials obtained from renewable plant, algae and animal sources, as well as from agroindustrial residues. Historically, some of them have been widely used by ancient populations for food packaging until these were replaced by petroleum-based plastic materials after World War II. Nowadays, biobased materials for food packaging have attracted attention. Their use was boosted especially because of the environmental pollution caused by inappropriate disposal of plastic packaging. Biobased materials are welcome to the design of food packaging because they possess many advantages, such as biodegradability, biocompatibility and low toxicity. Depending on the formulation, certain biopolymer-based packaging may present good barrier properties, antimicrobial and antioxidant activities Thus, polysaccharides and proteins can be combined to form diverse composite films with improved mechanical and biological behaviors, making them suitable for packaging of different food products.

Sustainable Bioactive Packaging Based on Thermoplastic Starch and Microalgae

This study combines the use of corn starch and Tetradesmus obliquus microalgae for the production of antioxidant starch films as flexible packaging material. Starch was plasticized with glycerol and blended with 1 w% polyallylamine chosen as an agent to modify the film physical properties. The addition of polyallylamine improved film water stability and water vapor transmission rate as well as mechanical stiffness and tenacity. The dried Tetradesmus obliquus microalgae, which showed an EC₅₀ value of 2.8 mg/mg DPPH (2.2-Diphenyl-1-picrylhydrazyl radical), was then used as antioxidant filler. The addition of microalgae provided the films with good antioxidant activity, which increased with microalgae content increasing. To our knowledge, this is the first study reporting the development of sustainable bioactive packaging films composed of almost 100% starch, and follows the European union's goals on plastics strategy concerning the promotion of bio-based, compostable plastics and the setting up of approaches to prevent food waste with a simple plastic packaging.

Wheat Biocomposite Extraction, Structure, Properties and Characterization: A Review

Biocomposite materials create a huge opportunity for a healthy and safe environment by replacing artificial plastic and materials with natural ingredients in a variety of applications. Furniture, construction materials, insulation, and packaging, as well as medical devices, can all benefit from biocomposite materials. Wheat is one of the world’s most widely cultivated crops. Due to its mechanical and physical properties, wheat starch, gluten, and fiber are vital in the biopolymer industry. Glycerol as a plasticizer considerably increased the elongation and water vapor permeability of wheat films. Wheat fiber developed mechanical and thermal properties as a result of various matrices; wheat gluten is water insoluble, elastic, non-toxic, and biodegradable, making it useful in biocomposite materials. This study looked at the feasibility of using wheat plant components such as wheat, gluten, and fiber in the biocomposite material industry.

Effect of Cross-Linking Modification on Structural and Film-Forming Characteristics of Pearl Millet (Pennisetum glaucum L.) Starch

Pearl millet starch was modified using epichlorohydrin (EPI) at different concentrations (0.1%; 0.3%; 0.5%; and 0.8%) and evaluated for physicochemical, rheological, in vitro digestibility, and film-forming characteristics. The degree of cross-linking was observed at higher levels (0.5% and 0.8%) of EPI. Upon cross-linking, breakdown and setback viscosity reduced whereas pasting temperature was increased. Storage modulus (G′) and loss modulus (G″) value of cross-linked (CL) starches ranged between 2877 to 5744 Pa and 168 to 237 Pa, respectively, during the frequency sweep test. A drastic decrease was observed for steady shear (yield stress and consistency index) characteristics of CL starches. Resistant starch (RS) content was increased after starch modification, which imparts its nutritional values and starch modified at 0.8% had the highest RS content. Modifications of starch at different levels had significant effects on the moisture, opacity, solubility and mechanical properties of films. Outcomes of this study will be helpful to understand the properties of native and CL starches for their potential applications in preparation of edible films.

Functional properties of starch-chitosan blend bionanocomposite films for food packaging: the influence of amylose-amylopectin ratios

The present study is focused on the influence of amylose and amylopectin ratio on crystallinity, water barrier, mechanical, morphological and anti-fungal properties of starch-based bionanocomposite films. The different sources of starch containing various proportion of amylose and amylopectin (high amylose corn starch, 70:30; corn starch, 28:72; wheat starch, 25:75; and potato starch, 20:80) has been incorporated with chitosan (CH) and nanoclay (Na-MMT). Amylose and amylopectin ratio has regulated the orientation of molecular structure in the starch-based films. Experimental results have revealed that the prepared bionanocomposite films that of CS/CH/nanoclay has exhibited higher crystallinity and molecular miscibility among corn starch, with chitosan and nanoclay were confirmed by XRD. CS/CH/nanoclay has exhibited lowest water vapor permeability and highest tensile strength due to molecular space present in corn starch. Fourier transform infrared spectroscopy has confirmed the shift of amine peak to a higher wavenumber indicating a stronger hydrogen bond between starch and chitosan. Finally, the best bionanocomposite films were tested for food packaging applications. Low-density polyethylene has exhibited fungal growth on 5th day when packed with bread slices at 25 °C and 59% RH whereas CS/CH/nanoclay bionanocomposite film did not show the same for at least 20 days. CS/CH/nanoclay film could potentially be useful for active packaging in extending shelf life; maintaining its quality and safety of food products thus substituting synthetic plastic packaging materials.

Approaches in Animal Proteins and Natural Polysaccharides Application for Food Packaging: Edible Film Production and Quality Estimation

Natural biopolymers are an interesting resource for edible films production, as they are environmentally friendly packaging materials. The possibilities of the application of main animal proteins and natural polysaccharides are considered in the review, including the sources, structure, and limitations of usage. The main ways for overcoming the limitations caused by the physico-chemical properties of biopolymers are also discussed, including composites approaches, plasticizers, and the addition of crosslinking agents. Approaches for the production of biopolymer-based films and coatings are classified according to wet and dried processes and considered depending on biopolymer types. The methods for mechanical, physico-chemical, hydration, and uniformity estimation of edible films are reviewed.

Exploration of in vitro drug release testing methods for saquinavir microenvironmental pH modifying buccal films

Buccal films containing a pH modifying excipient may be able to increase bioavailability of drugs with pH-dependent solubility such as saquinavir. Access to suitable in vitro drug release testing methods may facilitate buccal formulation development. This study aimed to explore two release testing methods for characterising buccal films and to elucidate the relationship between microenvironmental pH (pH_M, i.e. the pH around the swelling films) and saquinavir release. The Franz diffusion cell method was applicable to investigate the effect of hydroxypropyl methylcellulose (HPMC) grade on saquinavir release. Films containing HPMC K3 LV had a faster saquinavir release than films containing HPMC K100 LV. A UV/Vis imaging method was developed to visualise saquinavir release and pH_M changes during the initial dissolution. Within 5 min, the pH_M decreased from 6.8 to around 5.4 for HPMC K100 LV-based films containing 11.1 % or 16.6 % (w/w) malic acid. Subsequently, the pH_M increased due to increasing concentrations of saquinavir. An increase in malic acid content led to a faster saquinavir release. The combination of methods may be broadly applicable for excipient screening in development of buccal formulations. The imaging approach holds promise for characterizing other pH modifying formulation principles.

Trends in Chitosan as a Primary Biopolymer for Functional Films and Coatings Manufacture for Food and Natural Products

Some of the current challenges faced by the food industry deal with the natural ripening process and the short shelf-life of fresh and minimally processed products. The loss of vitamins and minerals, lipid oxidation, enzymatic browning, and growth of microorganisms have been the main issues for many years within the innovation and improvement of food packaging, which seeks to preserve and protect the product until its consumption. Most of the conventional packaging are petroleum-derived plastics, which after product consumption becomes a major concern due to environmental damage provoked by their difficult degradation. In this sense, many researchers have shown interest in edible films and coatings, which represent an environmentally friendly alternative for food packaging. To date, chitosan (CS) is among the most common materials in the formulation of these biodegradable packaging together with polysaccharides, proteins, and lipids. The good film-forming and biological properties (i.e., antimicrobial, antifungal, and antiviral) of CS have fostered its usage in food packaging. Therefore, the goal of this paper is to collect and discuss the latest development works (over the last five years) aimed at using CS in the manufacture of edible films and coatings for food preservation. Particular attention has been devoted to relevant findings in the field, together with the novel preparation protocols of such biodegradable packaging. Finally, recent trends in new concepts of composite films and coatings are also addressed.

Relevance of genipin networking on rheological, physical, and mechanical properties of starch-based formulations

The small amount of proteins in starch-rich food industry byproducts can be an advantage to crosslink with genipin and tailor the performance of biobased films. In this work, genipin was combined with non- purified starch recovered from industrial potato washing slurries and used for films production. Starch recovered from potato washing slurries contained 0.75% protein, 2 times higher than starch directly obtained from potato and 6 times higher than the commercial one. Starch protein-genipin networks were formed with 0.05% and 0.10% genipin, gelatinized at 75 °C and 95 °C in presence of 30% glycerol. Bluish colored films were obtained in all conditions, with the higher surface roughness (Ra, 1.22 μm), stretchability (elongation, 31%), and hydrophobicity (water contact angle, 127°) for 0.10% genipin and starch gelatinized at 75 °C. Therefore, starch-rich byproducts, when combined with genipin, are promising for surpassing the starch-based films hydrophilicity and mechanical fragilities while providing light barrier properties.

Carioca bean starch upon synergic modification: characteristics and films properties

BACKGROUND

The use of damaged beans for starch isolation comprises an end-use alternative for a product that is not accepted by the consumer. For that reason, isolation and modification of Carioca bean starch should be explored and evaluated as a suitable source for biodegradable material. The present study aimed to evaluate the synergism of physical and chemical modifications on Carioca bean starch with respect to improving the properties of biodegradable films. A heat-moisture treatment (HMT) followed by oxidation by sodium hypochlorite was performed and vice versa.

RESULTS

Synergism was noted in the starch properties compared to the single modification. When the oxidation was applied first, a higher amylose and carbonyl content was noted. HMT, isolated and as a second modification, caused a more pronounced effect on viscosity profile than the oxidized starch, with an increase in paste temperature and a decrease in viscosity, breakdown and final viscosity.

CONCLUSION

The results obtained in the present study reflect a decrease in water vapor permeability, although a higher tensile strength was noted when oxidation was applied, as a single and as a first modification. © 2020 Society of Chemical Industry.

Development, characterization and optimization of biopolymers films based on starch and flour from jabuticaba (Myrciaria cauliflora) peel

In this study, the influence of the concentration of flour from jabuticaba peel (FJP) and the concentration of glycerol (CG) on the physicochemical, barrier, mechanical, optical, spectroscopic and biodegradability properties of corn starch films was evaluated using response surface methodology. The increase in the concentrations of FJP and CG enhanced the thickness and permeability to water vapor, and made the films more hydrophilic. In addition to that, the interaction between the two variables caused reduction in the solubility of the films. High concentrations of FJP and CG reduced the maximum tensile strength, and increased CG increased the elongation and decreased the young's modulus of the films. Among the tests studied, the T1 film (15.80% FJP and 15.80% CG) was biodegradable, presenting the best mechanical and barrier properties such as low water vapor permeability, solubility and water holding capacity, showing great potential to be used as biodegradable packaging system.