Optimization of citron peel pectin and glycerol concentration in the production of edible film using response surface methodology

Pectin extracted from red dragon fruit (Hylocereus polyrhizus) peel and its usage in edible film

Pectin was extracted from red dragon fruit (Hylocereus polyrhizus) peel using two different extraction methods: subcritical water extraction (SCWE) and conventional acid extraction (AE), from two different types of peels, fresh peel puree and dried peel powder. SCWE method on fresh peel puree showed an ∼18.88 % increase in pectin yield compared to AE. Extracted pectin is classified as low methoxyl pectin (DE: 8.51-50.64 %), with an average molecular weight ranging from 115.23 kDa to 577.84 kDa and a Gal-A content of 44.09 % - 53.90 %. The potential of pectin from fresh peel puree to be applied as a biodegradable film was further explored. Different pectin concentrations (3-5 % w/v) were used to prepare the films. Regarding the film performance, PF-S5, which was produced from SCWE with 5 % of pectin concentration, exhibits better thermal stability (Tdmax 250 °C, residue of 28.69 %) and higher moisture barrier (WVP 5.59 × 10-11 g.cm-1.s-1.Pa-1). In comparison, PF-A showed lower water solubility (45.14-69.15 %), higher water contact angle (33.01° - 44.35°), and better mechanical properties (TS: 2.12-4.11 MPa, EB: 48.72-61.39 %). Higher molecular weight accompanied by higher DE and Gal-A content contributes to better pectin film properties.

Hybrid Metal Oxide (Ag-ZnO) Impregnated Biocomposite in the Development of an Eco-Friendly Sustainable Film

Nanotechnology offers an innovative application as an eco-friendly food packaging film fabricated along with a degradable active mixture (AM). The AM is an assortment of alloyed metal oxide nanoparticles (Ag-ZnO), citron powder (AA), and Curcuma peel powder (CPP). Alloyed nanoparticles (NPs) were observed to exhibit a hexagonal structure from the experimental X-ray diffraction. Compositional and morphological study of the NPs (22.69 nm) and AM (32 nm) was done using energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and ζ- potential was observed to be -14.7 mV, indicating the stability of NPs. The prepared film was observed to be more effective with antibacterial analysis against Escherichia coli, exhibiting 72% of inhibition and antioxidant activity with IC50: 51.56% using the 2,2 diphenyl-1-picrylhydrazyl (DPPH) assay. Film 1, Film 2, Film 3, and Film 4 were fabricated with the AM and observed to be perfectly encapsulated by PVA using XRD. FESEM images of the film exhibit the aggregation of NPs with biocomposites in perfect distribution. The mechanical properties such as Young's modulus, elongation at break, tensile strength, and ultimate tensile strength (UTS- 5.37 MPa) were experimented for the films. The degradation rate was observed to be 6.12% for film 1 using the soil burial method. The study emphasizes that NPs along with biocomposite upgrade the sustainability of the packaging film with improved mechanical and physicochemical properties. The synthesized film with biomaterials could be used as a "green" food package to store fruits, vegetables, and sweets in the food industry.

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.

Synthesis and characterization of polysaccharide- and protein-based edible films and application as packaging materials for fresh fish fillets

The rising packaging industry together with global demand for sustainable production has increased the interest in developing biodegradable packaging materials. The aim of the study was to develop edible films based on pectin, gelatin, and hydroxypropyl methylcellulose and evaluate their applicability as biodegradable packaging materials for gilthead seabream fillets. Mechanical properties, water barriers, wettability of the films through contact angle measurement, optical, and UV-Vis barrier properties were evaluated for food packaging applications. The effective blend of polysaccharide and protein film-forming solutions was confirmed by the produced films with excellent optical properties, acceptable mechanical properties and adequate barriers to water vapor. The contact angle for pectin based and gelatin based films were higher than 90° indicating the hydrophobic films, while HPMC based films had contact angle lower than 90°. The produced films were tested as alternative and environmentally friendly packaging materials for gilthead seabream fillets during refrigerated storage. All tested packaging conditions resulted in similar shelf-life in packed gilthead seabream fillets (i.e. 7-8 days at 2 °C). The results showed that the developed films may reduce the use of conventional petroleum-based food packaging materials without affecting the shelf-life of fish.