Effect of Cross-Linking with Aloe vera Gel on Surface and Physicochemical Properties of Edible Films Made from Plantain Flour

Intrinsic challenges and strategic approaches for enhancing the potential of natural rubber and its derivatives: A review

Natural rubber (NR) and its derivatives play indispensable roles in various industries due to their unique properties and versatile applications. However, the widespread utilization of NR faces intrinsic challenges such as limited mechanical strength, poor resistance to heat and organic solvent, poor electrical conductivity, and low compatibility with other materials, prompting researchers to explore enhancing its performance. Modified NRs (MNRs) like cyclization, deproteinization, chlorination, epoxidation, or grafting NR demonstrated a few enhanced merits compared to NR. However, various strategies, such as blending, vulcanization, crosslinking, grafting, plasticization, reinforcement, and nanostructuring, overcame most drawbacks. This review comprehensively examines these challenges and delves into the modification strategies employed to enhance the properties and expand the applications of NR and its derivatives. Furthermore, the review explores future visions for the NR industry, emphasizing integrating advanced modification techniques, adopting sustainable practices, and promoting circular economy principles. By elucidating the inherent challenges, outlining effective modification strategies, and envisioning future trajectories, this review provides valuable insights for stakeholders seeking to navigate and contribute to the sustainable development of the NR sector.

Fabrication and characterization of talipot starch-based biocomposite film using mucilages from different plant sources: A comparative study

Biocomposite films were prepared by formulating talipot starch with plant mucilage derived from shoeblack leaves, okra, and seeds of basil, fenugreek, and flax, which were identified as SBM-TSF, OKM-TSF, BSM-TSF, FGM-TSF, and FXM-TSF, respectively. The plant mucilages enhanced the crosslinking of the filmogenic solutions, which increased the film's relative crystallinity. Upon topographical investigation, the biocomposite films exhibited the same compact and homogeneous structures as the native talipot starch film (NTSF), but with finer corrugations. When compared to NTSF, the addition of plant mucilage decreased the moisture content while increasing the thickness and opacity. SBM-TSF showed significantly reduced (p ≤ 0.05) solubility and water vapor permeability, indicating that increased crosslink formation in the film obstructed the water vapor passage. Among all the biocomposite films, the BSM-TSF had the greatest tensile strength, making it more resistant to stretching. Among the studied biocomposite films, SBM-TSF and BSM-TSF demonstrated improved thermal and biodegradation stability.

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.

Production of Thermoplastic Starch-Aloe vera Gel Film with High Tensile Strength and Improved Water Solubility

Biodegradable film packaging made from thermoplastic starch (TPS) has low mechanical performance and high water solubility, which is incomparable with synthetic films. In this work, Aloe vera (AV) gel and plasticized soluble potato starch were utilised to improve the mechanical stability and water solubility of TPS. Dried starch was mixed with glycerol and different AV gel concentrations (0% to 50%). The TPS + 50% AV gel (30 g TPS + 15 g AV gel) showed the best improvement compared to TPS alone. When compared to similar TPS films with AV gel added, this film is stronger and dissolves better in water. Mechanical qualities improved the tensile strength and Young's modulus of the TPS film, with 1.03 MPa to 9.14 MPa and 51.92 MPa to 769.00 MPa, respectively. This was supported by the improvement of TPS water solubility from 57.44% to 46.6% and also by the increase in decomposition temperature of the TPS. This promises better heat resistance. The crystallinity percentage increase to 24.26% suggested that the formation of hydrogen bonding between TPS and AV gel enhanced crosslinking in the polymeric structure. By adding AV gel, the TPS polymeric structure is improved and can be used as a biodegradable food-packaging film.

Development of Aloe Vera-Green Banana Saba-Curcumin Composite Film for Colorimetric Detection of Ferrum (II)

This study was performed to develop and characterize a bio-film composed of Aloe vera (Aloe barbadensis), green banana Saba (Musa acuminata x balbisiana), and curcumin for the detection of Fe²⁺ ions. Cross-linking interaction between banana starch-aloe vera gel and banana starch-curcumin enhanced l the sensing performance of the composite film towards divalent metal ions of Fe²⁺. The morphological structure of the Aloe vera-banana starch-curcumin composite revealed a smooth and compact surface without cracks and some heterogeneity when observed under Scanning Electron Microscopy (SEM). The thickness, density, color property, opacity, biodegradation, moisture content, water-solubility, water absorption, swelling degree, and water vapor permeability of bio-films were measured. The incorporation of aloe vera gel and curcumin particles onto the banana starch film has successfully improved the film properties. The formation of the curcumin-ferrum (II) complex has triggered the film to transform color from yellow to greenish-brown after interaction with Fe²⁺ ions that exhibit an accuracy of 101.11% within a swift reaction time. Good linearity (R² = 0.9845) of response on colorimetric analysis was also obtained in Fe²⁺ ions concentration that ranges from 0 to 100 ppm, with a limit of detection and quantification found at 27.84 ppm and 92.81 ppm, respectively. In this context, the film was highly selective towards Fe²⁺ ions because no changes of color occur through naked eye observation when films interact with other metal ions, including Fe³⁺, Pb²⁺, Ni²⁺, Cd²⁺, and Cu^2+. Thus, these findings encourage curcumin-based starch films as sensing materials to detect Fe²⁺ ions in the field of food and agriculture.

Developing multifunctional edible coatings based on alginate for active food packaging

The applications of edible coatings stemmed exclusively from alginate in food packaging are restricted due to their inherent deficient antimicrobial, barrier, and UV-barrier properties. In this work, we aimed to design smart alginate-based coatings for active food packaging through the addition of both aloe vera (AV) and garlic oil (GO). The interactions between the film components were verified by FTIR and XRD. Thermal and mechanical properties were improved by the presence of AV and GO. The presence of AV and GO did not significantly influence the transparency of alginate films. The films exhibited a significant UV-shielding to all UV regions. Water vapor permeability was significantly (p < 0.05) reduced either through the incorporation of AV or GO. The antimicrobial properties of the prepared films were considerably improved by the presence of AV and GO. The shelf-life of tomatoes (Solanum lycopersicum L.) was extended when coated with the alginate film incorporated with AV and GO. Owing to the outstanding UV-shielding, mechanical, thermal, and antimicrobial properties, the alginate/AV/GO active coatings could potentially be implemented in the food packaging industry.

Development and Characterization of Novel Composite Films Based on Soy Protein Isolate and Oilseed Flours

The possibility of using oilseed flours as a waste source for film-forming materials with a combination of soy protein isolate in preparation of edible films was evaluated. Physical, mechanical and barrier properties were determined as a function of the oilseed type: hemp, evening primrose, flax, pumpkin, sesame and sunflower. It was observed that the addition of oilseed flours increased the refraction and thus the opacity of the obtained films from 1.27 to 9.57 A mm⁻¹. Depending on the type of flours used, the edible films took on various colors. Lightness (L*) was lowest for the evening primrose film (L* = 34.91) and highest for the soy protein film (L* = 91.84). Parameter a* was lowest for the sunflower film (a* = −5.13) and highest for the flax film (a* = 13.62). Edible films made of pumpkin seed flour had the highest value of the b* color parameter (b* = 34.40), while films made of evening primrose flour had the lowest value (b* = 1.35). All analyzed films had relatively low mechanical resistance, with tensile strength from 0.60 to 3.09 MPa. Films made of flour containing the highest amount of protein, pumpkin and sesame, had the highest water vapor permeability, 2.41 and 2.70 × 10⁻⁹ g·m⁻¹ s⁻¹ Pa⁻¹, respectively. All the edible films obtained had high water swelling values from 131.10 to 362.16%, and the microstructure of the films changed after adding the flour, from homogeneous and smooth to rough. All blended soy protein isolate–oilseed flour films showed lower thermal stability which was better observed at the first and second stages of thermogravimetric analysis when degradation occurred at lower temperatures. The oilseed flours blended with soy protein isolate show the possibility of using them in the development of biodegradable films which can find practical application in the food industry.

Study of morphological, structural, thermal, and pasting properties of flour and isolated starch from unripe plantain (Musa paradisiaca)

This work focused on studying the mineral composition, morphology, thermal, structural, and pasting properties of isolated plantain starch. Plantain starch is rich in K, and other ions as Mg, Ca, P, and Si were found. This starch exhibits lenticular, elliptical, and semispherical morphologies. Two endothermal events present in the thermogram were identified as the hexagonal and orthorhombic solvation. C-type starch formed by hexagonal and orthorhombic nanocrystal was completely indexed. The ash content showed the presence of calcium phosphate (KCaP₂O₇), Calcium Magnesium Phosphate (Ca_2.71Mg_0.29(PO₄)₂), and silicon oxide (SiO₂). The pasting profile of this starch behaves between a custard and a hydrogel. Scanning electron microscopy of the lyophilized samples along pasting profile confirms that the shear and van der Walls forces and slurry morphology govern the pasting profile changes.

Evaluation of bioactive release kinetics from crosslinked chitosan films with Aloe vera

Thermocompression was employed to prepare citric acid-crosslinked chitosan films with Aloe vera (AV) as bioactive compound. Films were easy to handle and mechanical properties did not change with the addition of AV up to 10 wt%, although both TS and EAB decreased for the films with 15 wt% AV, indicating that high AV contents would hinder intermolecular interactions among the formulation components. Maillard reaction occurred between chitosan and citric acid at the processing temperature used (115 °C), while physical interactions took place with AV, as shown by FTIR analysis. All films were insoluble but displayed hydration and limited swelling due to both physical and chemical interactions promoted by AV and citric acid, respectively. A slow AV release, governed by a Fickian diffusion controlled mechanism, and an increase of surface hydrophilicity, which favors cell adhesion, were observed.

Reactive extrusion-processed native and phosphated starch-based food packaging films governed by the hierarchical structure

The aim of this research work was to investigate novel tools given by nanotechnology and green chemistry for improving the disadvantages typically associated to the starch-based films: water susceptibility and brittle mechanical behavior. With this in mind, four food packaging film systems were developed from corn starch or corn starch nanocrystals (SNCs), and modified by phosphating under reactive extrusion (REx) conditions using sodium tripolyphosphate (Na₅P₃O₁₀ - TPP) as a crosslinker. The structural, physicochemical, thermal, rheological and mechanical properties, as well as studies associated with the management of carbohydrate polymer-based plastic wastes (biodegradability and compostability) were carried out in this study. The hierarchical structure and the modification of the starch were dependent on the amylose content and degree of substitution (DS), which in turn depended on the hydrogen (H)-bonding interactions. In both cases, a higher molecular ordering of the starch chains in parallel was decisive to obtain the self-assembled thermoplastic starches. Beyond the valuable results obtained and scientifically analyzed, unfortunately none of the manufactured materials achieved to improve their performance compared to the control film (thermoplastic starch - TPS). It was even thought that the phosphated starch-based films could fertilize lettuce (Lactuca sativa) seedlings during their biodegradation, and this was not achieved either. This possibly due to the low content of phosphorus or its poor bioavailability.

Edible films and coatings for shelf life extension of mango: a review

Edible films and coatings are eco-friendly promising materials for preserving the quality and extending the shelf life of fresh and minimally-processed fruits. They can form protective layers around fruits, regulate their respiration rates, and protect them from loss of water, tissue softening, browning, and microbial contamination. Edible films and coatings have many advantages over other post-harvest treatments. They can add commercial value to fruits by enhancing their appearance, and act as carriers of functional ingredients, such as antioxidants, antimicrobial agents and nutraceuticals. Mango, a highly perishable tropical fruit, has a short post-harvest life, which limits transport to distant markets. Application of edible films and coatings on mango fruits is an effective method to preserve their quality and safety. This paper provides an overview of desirable properties for films and coatings, and recent development in different edible coatings for both fresh and minimally-processed mango. The most popular edible coating materials, such as chitosan, waxes, starch, gums, and cellulose used for mango are reviewed. The commercialization of coating formulations and equipment used for application of coatings are discussed. The environmental impacts, safety aspects, and the challenges encountered are outlined. The opportunities to use other coating materials, such as aloe-vera gel, microbial polysaccharides, and photosynthetic microorganisms are also examined.

Chemical Constituents, Antimicrobial Activity, and Food Preservative Characteristics of Aloe vera Gel

Edible coating gels developed from the Aloe vera plant have been used as a traditional medicine for about 3000 years. Aloe vera contains approximately 110 potentially active constituents from six different classes: chromone and its glycoside derivatives; anthraquinone and its glycoside derivatives; flavonoids; phenylpropanoids and coumarins; phenylpyrone and phenol derivatives; and phytosterols and others. Apart from medicinal uses, Aloe gels have an important role in food preservation as edible coatings. They provide an edible barrier for atmospheric gases and moisture and help to reduce the respiration and transpiration of fresh produce, which helps to preserve its postharvest quality. To date, numerous studies have been conducted on the postharvest use of Aloe vera gel. The present review article summarizes and discusses existing available information about the chemical constituents, antimicrobial activity, and food preservative characteristics of Aloe vera.

The influence of Aloe vera gel incorporation on the physicochemical and mechanical properties of banana starch-chitosan edible films

BACKGROUND

Aloe vera (AV) gel is a promising material in food conservation, given its widely reported antimicrobial and antioxidant activity; however, its application in the formation of edible films and coatings has been small owing its low film-forming capability. The aim of this study was to investigate the physicochemical properties of film-forming solutions and films prepared using unripe banana starch-chitosan and AV gel at different AV gel concentrations.

RESULTS

Our results showed that AV gel considerably affected the rheological and optical properties of the edible coatings, mainly due to increased amounts of solids brought by the AV gel. Film-forming capacity and physicochemical properties were also studied; most of the film properties were affected by the inclusion of AV gel, with decreased water vapor permeability, tensile strength and elongation at break. Fourier transform infrared studies showed that the inclusion of AV gel disrupts the interaction between starch and chitosan molecules; however, further studies are needed to fully understand the specific interactions between the components of AV gel and both starch and chitosan molecules.

CONCLUSION

Our results suggest that the addition of AV gel creates a crosslinking effect between the phenolic compounds in AV gel and starch molecules, which disrupts the starch-chitosan interaction and greatly affects the properties of both the film-forming solution and edible films. © 2018 Society of Chemical Industry.

Structural properties and in vitro digestibility of edible and pH-sensitive films made from guinea arrowroot starch and wastes from wine manufacture

A non-conventional starch obtained from guinea arrowroot tubers (Calathea allouia) grown in the Amazon was used as a polymeric matrix for the development of edible films. The films were manufactured by blending/thermo molding and plasticized with glycerol. Agro-industrial wastes from wine manufacture (grape waste flour and grape waste extract) were used as natural fillers of the thermoplastic starch (TPS) matrices. The results showed that the natural fillers caused cross-linking in the TPS matrix. This led to the production of films with higher resistant starch (RS) content, especially RS type 4 (RS4), although the DSC results showed that the films developed also contained RS type 3 (RS3). As expected, the presence of RS reduced the in vitro digestibility rate. Films made with the natural fillers were also less hydrophilic, had a greater thermal resistance, and tended towards ductile mechanical behavior. Finally, the edible film containing grape waste flour as a natural filler proved to be pH-sensitive, although this material disintegrated under alkaline conditions.