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Graphical abstract Highlights • SPNCCs were successfully isolated from sugar palm fibres via hydrolysis process. • The SPS/SPNCCs showed improvement in mechanical, thermal and physical properties. • The 0.5 wt% SPNFCs loaded SPS films showed 140% improved tensile strength. • WA, WS and WVTR results showed improved water barrier property of SPS/SPNFCs film. Abstract Sugar palm fibre (SPF) was treated with NaClO 2 , bleached with NaOH and subsequently hydrolyzed with acid to obtain sugar palm nanocrystalline cellulose (SPNCCs). Bionanocomposites in the form of films were prepared by mixing sugar palm starch (SPS) and sorbitol/glycerol with different nanofiller SPNCCs compositions (0–1.0 wt%) using solution casting method. The resulting fibres and nanocomposites were characterized in terms of morphology (FESEM and TEM), footprint, crystallinity (XRD), light transmittance, biodegradability, physical, water barrier, thermal (TGA, DSC and DMA) and mechanical properties. The length (L), diameter (D) and L/D values of the SPNCCs were 130 ± 30.23, 8.5 ± 1.82 nm, and 15.3, respectively. The SPS/SPNCCs nanocomposite films exhibited higher crystallinity, tensile strength, Young's modulus, thermal and water-resistance compared to the neat SPS film. The results showed that the tensile strength and moduli of the bionanocomposites increased after being reinforced with SPNCCs and the optimum nanofiller content was 0.5%. [ABSTRACT FROM AUTHOR]

Wheat straw has been used as a source of hemicelluloses (WSH) and cellulose nanocrystals (CNC) for the elaboration of biodegradable films. Different films have been formed by using WSH as a matrix and different contents of CNC and citric acid. The predominant hemicelluloses were arabinoxylans. CNC reinforced the films, improving tensile strength and modulus, water resistance and water vapor barrier. Citric acid, on the other hand, presented concomitant plasticizing and crosslinking effects (the latter also evidenced by FTIR), probably due to a crosslinking extension by glycerol. The use of 5.9 wt% CNC and 30 wt% citric acid was defined as optimal conditions, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile properties. Under those conditions, the films presented enhanced modulus, elongation, water resistance, and barrier to water vapor when compared to the control WSH film, and might be used for wrapping or coating a variety of foods. [ABSTRACT FROM AUTHOR]

Current trends in food packaging systems are toward biodegradable polymer materials, especially the food biopolymer films made from polysaccharides and proteins, but they are limited by mechanical strength and barrier properties. Nano-chitin has great economic value as a highly efficient functional and reinforcing material. The combination of nano-chitin and food biopolymers offers good opportunities to prepare biodegradable packaging films with enhanced physicochemical and functional properties. This review aims to give the latest advances in nano-chitin preparation strategies and its uses in food biopolymer film reinforcement and applications. The first part systematically introduces various preparation methods for nano-chitin, including chitin nanofibers (ChNFs) and chitin nanocrystals (ChNCs). The nano-chitin reinforced biodegradable films based on food biopolymers, such as polysaccharides and proteins, are described in the second part. The last part provides an overview of the current applications of nano-chitin reinforced food biopolymer films in the food industry. [ABSTRACT FROM AUTHOR]

The effects of the amylose content and the preparation sequence in physicochemical properties of starch/montmorillonite (MMT) composites were studied in this work. Native (30%) and high amylose Hylon VII (70%) starches were considered for assessing the effects of amylose content. Glycerol and MMT were used as additives to evaluate the effects of the former as plasticizer and the latter as reinforcer. The glycerol was incorporated before (Method M1) and after (Method M2) the addition of MMT. FTIR studies indicated that water bonding was affected by amylose content. Sorption isotherms indicated that method M2 favoured water adsorption and method M1 reduced water adsorption due to competition for active sites for interaction. TGA showed that method M1 induced a higher degradation rate than method M2. Wettability analysis by contact angle measurements showed that plasticizer promoted the hydrophilicity of the film, whereas MMT promoted a hydrophobic surface for both cases of amylose content. [ABSTRACT FROM AUTHOR]

This paper reports the use of acetylated starch nanoparticles (NPAac) as reinforcement in thermoplastic starch films. NPAac with an average size of approximately 500 nm were obtained by nanoprecipitation. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) indicated that NPAac are more thermally stable and essentially amorphous when compared with acetylated starch. Thermoplastic starch films with different proportions of NPAac (0.5, 1.0, 1.5, 10.0%, w/w) were obtained and characterized by scanning electron microscopy (SEM), water vapor permeability (WVP), adsorption isotherms, TGA and mechanical tests. The inclusion of reinforcement caused changes in film properties: WVP was lowered by 41% for film with 1.5% (w/w) of NPAac and moisture adsorption by 33% for film with 10% (w/w) of NPAac; and the Young's modulus and thermal stability were increased by 162% and 15%, respectively, for film with 0.5% (w/w) of NPAac compared to the starch film without the addition of NPAac. [ABSTRACT FROM AUTHOR]

Highlights: [•] Addition of nanocellulose to chitosan polymer improved a* and b* values. [•] Decreasing glycerol concentration plunged water solubility and WVP values of the nanocomposites. [•] Nanoparticles were dispersed better into chitosan matrix with increasing glycerol concentrations. [•] Random direction of cellulose nanocrystals into chitosan matrix was implemented. [ABSTRACT FROM AUTHOR]

Abstract: The development of commercially viable “green products”, based on natural resources for the matrices and reinforcements, in a wide range of applications, is on the rise. The present paper focuses on Sterculia urens short fiber reinforced pure cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has taken place. SUSF/cellulose composite films have great potential in food packaging and for medical applications. [Copyright &y& Elsevier]

Abstract: Starch extruded in the presence of a plasticizer results in a material called thermoplastic starch (TPS). TPS mixed with poly(butylene adipate co-terephthalate) (PBAT), soybean oil (SO), and surfactant may result in films with improved mechanical properties due to greater hydrophobicity and compatibility among the polymers. This study characterized films produced from blends containing 65% TPS and 35% PBAT with SO added as compatibilizer. The Tween 80 was added to prevention of phase separation. The elongation and resistance were greater in the films with SO. The infrared spectra confirmed an increase in ester groups bonded to the PBAT and the presence of groups bonded to the starch ring, indicating TPS–SO and PBAT–SO interactions. The micrographs suggest that the films with SO were more homogenous. Thus, SO is considered to be a good compatibilizer for blends of TPS and PBAT. [Copyright &y& Elsevier]

Abstract: In this work, the film-forming capacity of the new microbial exopolysaccharide (EPS) composed by sugars and acyl groups, produced by Pseudomonas oleovorans NRRL B-14682, was studied. The films were transparent and quite flexible and tough when handled, but showed to be stiff under tensile and puncture tests. They presented a high water vapour permeability but a quite low permeability to carbon dioxide, which are typical of hydrophilic polysaccharide films. Furthermore, they showed good stability in contact with liquid water, after auto-crosslinking reactions at low pH, upon or after drying. Preliminary biodegradability tests indicated an easy biological degradation when exposed to soil microorganisms. The results obtained are rather promising regarding the film-forming capacity of the new EPS, as they were obtained only with the biopolymer itself. The films formulation may be complemented with additives (e.g. plasticizers, emulsifiers, nanocomposites), to design films for specific applications. [Copyright &y& Elsevier]

Abstract: In this work, the enhancement of the barrier properties to water vapour and gases (CO2 and O2) of a polymeric matrix composed by kappa-carrageenan and pectin (66.7% kappa-carrageenan), with the inclusion of mica flakes, was studied. The effect of the films mica content on the water vapour permeability (WVP) was dependent on the driving force applied. A higher WVP reduction (of about 40% for a mica content of 10%, mass of mica per mass of dry polymer), was observed when the films were more homogenously hydrated throughout their thickness. A significant decrease was also observed for both CO2 and O2 permeabilities (73% and 27%, respectively), in conditions where the films were plasticized with water (25% of water, dry basis), for which there is a depletion of the good barrier properties characteristic of dry polysaccharide films. In addition, the composition of 10% of mica flakes in the polymer matrix represented a critical volume fraction of inorganic particles, above which there was a decrease of the films barrier properties, for all components tested. [Copyright &y& Elsevier]

Abstract: The aim of this work was to develop biodegradable films based on blends of Amaranthus cruentus flour and poly(vinyl alcohol). Five different PVA types were tested. Blends with higher hydrolysis (HD) degree PVA were more resistant, showing greater tensile strength (TS) and puncture force (PF). However, the films with PVA with lower HD showed more flexibility, greater elongation at break (ELO) and greater puncture deformation (PD), with the exception of PVA 325. The latter was chosen due to it superior mechanical performance (TS=10.2MPa, ELO=89.8%, PF=9.4N and PD=16.3%). When films based on blends of amaranth flour and PVA 325 (10–50%) were evaluated, all mechanical properties were enhanced with increase in PVA 325 content. The solubility in water of the films made with PVA and amaranth flour decreased with increasing PVA content, reaching 44% of soluble matter for the 50% PVA film. The formation of hydrogen bonds between the blend components was confirmed by the FTIR spectra analysis. [Copyright &y& Elsevier]

Abstract: Effects of plasticizers (glycerol, sorbitol, and 1:1 mixture of glycerol and sorbitol) on moisture sorption characteristics of cassava starch films were investigated at three levels of plasticizer concentration (0, 20, and 40g/100g starch). The combined effects of relative humidity and plasticizer on mechanical properties of starch films were also examined. Water affinities of cassava starch films were affected by hydrophilicity of the plasticizer and its concentration. Films plasticized with glycerol, under all RH conditions, adsorbed more moisture with higher initial adsorption rate, and films with higher plasticizers contents exhibited higher equilibrium moisture contents. Mechanical properties were affected by plasticizing effect, including the water adsorbed, resulting in higher strain and Young''s modulus values for starch films and, in all cases, glycerol exerted a more effective plasticization. [Copyright &y& Elsevier]

Chitosan (CH) and methylcellulose (MC) are hydrocolloids with good film-forming properties. The objectives of the present work were to characterize: (i) rheological and surface tension properties of the filmogenic suspensions and (ii) water solubility, color, mechanical properties and water vapor permeability of the composite films.Suspensions of 1 and 2% CH and 1% MC were mixed in different proportions. Surface tension of filmogenic suspensions ranged between 72 and 87.5 dyn cm-1. All suspensions were pseudoplastic; apparent viscosity and consistency index of the mixtures were higher than those of MC or CH suspensions. Films were obtained by casting. Water vapor permeabilities for CH and MC films were 9.03±0.12×10-11 and 7.55±0.60×10-11 g s-1 mPa-1, respectively; intermediate values were obtained for the composite films. CH films showed rigid characteristics (high elastic modulus and small elongation). Film flexibility increased with increasing MC content, the higher elongation and lower elastic modulus of composite films indicated the relevance of hydrocolloid interactions. [Copyright &y& Elsevier]

Yam starch films were produced by thermal gelatinization of starch suspensions using different starch and glycerol concentrations and were compared to control samples without glycerol. Films were characterized by polarized light microscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermomechanical analysis (TMA), X-ray diffraction, water vapor permeability (WVP) and water sorption isotherms. The polarized light microscopy and DSC data showed that starch gelatinization for film formation was complete. Plasticized films have a homogeneous structure as observed by SEM. At water activities >0.43, glycerol increased the equilibrium moisture content of the films due to its hydrophilic character. X-ray pattern of the yam films could be assigned to a B-type starch; during storage this pattern remained almost the same, however a slight recrystallization process could be observed. Amylopectin retrogradation was not observed by DSC with storage time of the films. Glass transition temperatures of films with glycerol were lower than those of control films as measured by DSC and TMA. WVP of yam starch films increased with the presence of glycerol. [Copyright &y& Elsevier]

Tensile strength and elongation at break of corn starch-based films formulated with ZYO • Zanthoxylum bungeanum essential oil (ZYO) was incorporated into starch films using a solution casting method. • The addition of ZYO improved the elongation at break and thickness of corn starch-based films. • The addition of ZYO reduced the moisture content and water vapor permeability of corn starch-based films. • The addition of ZYO increased the surface roughness and decreased the gloss of corn starch-based films. • ZYO can be used in preparation of antibacterial biodegradable films for various food packaging applications. Herein, corn starch-based films were prepared by casting method and different concentrations of Zanthoxylum bungeanum essential oil (ZYO) were added to evaluate the morphological, optical, mechanical, and barrier properties of the resultant films. Additionally, structural analysis was carried out via atomic force microscopy and the antibacterial activities against Staphylococcus aureus , Escherichia coli , and Listeria monocytogenes were assessed. We found that the elongation at break was significantly increased (P < 0.05), whereas tensile strength, moisture content, solubility in water, and water vapor permeability rate were significantly decreased (P < 0.05) in films incorporated with ZYO compared with oil-free films. Furthermore, incorporation of ZYO increased the opacity and decreased the gloss of films. Incorporation of ZYO appears to increase the surface roughness and the antibacterial activity of the films. In sum, ZYO can potentially be used in food packaging, particularly food intended to be protected from light and susceptible to spoilage by microorganisms. [ABSTRACT FROM AUTHOR]

• Use of low magnetic field for the alignment of CNC in starch based nanocomposites. • Effect of MF and AS of CNC on mechanical and physicochemical property is studied. • Tensile strength increased by 95 % with MF and high AS T-CNC compared to P-CNC. • Modulus increased by 67 % with MF and high AS T-CNC compared to P-CNC. • Higher hydrophobicity with MF and high AS T-CNC compared to P-CNC. The magnetic field (MF) induced alignment of cellulose nanocrystals (CNC) within a starch matrix is investigated and its effect on the physicochemical and mechanical properties of the nanocomposites are discussed in the paper. Two different kinds of CNC i.e. plant-CNC and tunicate-CNC and its hybrid combination are studied to understand the effect of aspect ratio of CNC on the properties of nanocomposite. Nanocomposites with tunicate sourced CNC showed higher tensile strength and modulus, and lower water vapor permeability as compared to plant sourced CNC. These properties are higher for nanocomposites prepared under MF. The modulus of starch nanocomposites increased from 0.26 GPa and 0.32 GPa to 0.38 GPa and 0.44 GPa, respectively for plant-CNC and tunicate-CNC when exposed to MF. The improved orientation and alignment of CNC in presence of MF is further supported by Raman and scanning electron micrographs studies. [ABSTRACT FROM AUTHOR]