Plastics are being used as effective packaging material for food preservation, but their diminishing resources and damaging impact on the environment are important factors driving the need for the development of food packaging from renewable and biodegradable natural polymers. Many naturally occurring hydrocolloids were utilized for the development of edible coatings and films. One of the most important among such hydrocolloids is sodium alginate (Tavassoli-Kafrani et al., 2016) which is extracted from brown seaweed and is used as a thickening and stabilizing agent in various food and non-food products (Benavides et al., 2012;Liakos et al., 2013;Nair et al., 2018). Chemical structure of alginate generally comprises (1 → 4)-linked α-l-guluronic acid(G)and β-d-mannuronic acid(M). Depending on the species of brown algae, guluronic and mannuronic acids are arranged in homogeneous blocks (GG or MM)

Biodegradable films based on sodium alginate and aloe vera were prepared by casting technique. The resulting films were characterized by swelling behavior, scanning electron microscopy, biodegradation, as well as mechanical and barrier properties. The aloe vera gel exerted a positive influence on mechanical and physico-chemical properties. Aloe vera gel improved the tensile strength of the films giving maximum value of 21.20 N/mm 2 at 20% gel. Water vapor permeability of the composite films was reduced which made the film more effective as a moisture barrier, giving the most efficient result of 1.16 Â 10 À10 g m À1 s À1 Pa À1 at 50% aloe vera gel. The present study demonstrates the viability of the composite alginate aloe vera films as a biodegradable alternative to synthetic plastic films for the packaging of food materials.

Biopolymers like polysaccharides are being used to develop biodegradable and edible food packaging films. These films are environment friendly but have inferior mechanical strength as compared to conventional plastics. This study seeks to enhance the mechanical properties of alginate aloe vera composite films by the fusion of organic fibers like carboxymethyl cellulose (CMC) and hydroxypropyl methylcellulose (HPMC). CMC and HPMC were added at varying concentrations (2%–14%).Addition of both these cellulose derivatives had a positive effect on the tensile strength and elongation at break of the composite films. The tensile strength increased to a maximum value of 35.08 and 51.96 N/mm2 in CMC and HPMC films, respectively at 4% concentration of both. Increasing the fiber concentration further resulted in a decrease of tensile strength. Similar trend was observed in the flexibility of the films as the elongation at break value was maximum 5.57% and 3.21%, respectively at 4% concentration. The addition of CMC reduced the water solubility of the film. The solubility decreased to 19% at the maximum concentration of CMC. The effect of HPMC on water solubility was opposite to that of CMC. The solubility of the film increased to 86.42% at highest concentration of HPMC. CMC slowed down the biodegradation rate of the films whereas HPMC increased it.

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A novel starch source from water chestnut (WCS) was used to develop composite film with polyvinyl alcohol (PVA) and different plasticizer's effects on functional properties were investigated. Results showed that the plasticizer decreased the swelling capacity but conversely increased the film solubility. The tensile strength (TS) of WCS-PVA film improved when incorporating plasticizer but gradually reduced at higher plasticizer concentration. The TS reached the maximum value of 28.82 and 17.14 MPa with sorbitol and glycerol, respectively, at 20% concentration. Conversely, elongation at break was decreased first and then increased with concentration. The water vapor permeability was observed to be slightly increased from 1.698 × 10 −10 to 1.744 × 10 −10 g Pa −1 m −1 s −1 for G-plasticized films and 1.124 × 10 −10 to 1.134 × 10 −10 g Pa −1 m −1 s −1 for S-plasticized films. Also, the result indicated that the incorporation of plasticizers enhanced biodegradability and made them suitable for food packaging without any hazardous effects. Novelty impact statementIn previous work, starch-based films with polyvinyl alcohol (PVA) were prepared from different starch sources. However, no study has been reported so far on biocomposite film made from water chestnut with PVA. This paper was reported for the first time for the development of WCS-PVA biocomposite film and demonstrated the different plasticizer effects on its physical, barrier, and mechanical properties.