Lower Water Vapor Permeability Research Articles

Films properties of QPM corn starch with Delonix regia seed galactomannan as an edible coating material

Plant-based polysaccharides are considered a good alternative for obtaining edible films and coatings. In this research the objective was to determine the physicochemical characteristics of corn starch obtained from QPM Sac-Beh (SBCS) and Delonix regia galactomannan (DRG) and use them to produce films. Films were elaborated from 1 %(w/v) film-forming solutions (FFS) with SBCS:DRG 1:0, 1:1, and 0:1 ratio. Some films were prepared with glycerol 0.4 %(w/v) and vanillin 0.1 %(w/v). SBCS and DRG were characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and differential scanning calorimetry. SBCS presented low crystallinity which agrees with a low gelatinization ΔH observed. The SBCS:DRG 1:0 FFS without glycerol did not form films; however, DRG addition allows film formation. It was also found that glycerol addition reduced tensile strength to 10.3 MPa, from 41.3 MPa. The lowest water vapor permeability was found in films with 1:1 SBCS:DRG and 0.1 %(w/v) vanillin. This formulation was used to coat D'Anjou pears. This coating conserved the pears' color for 24 days while the control ones started to get a brown color on day 6. Based on the results obtained, FFS elaborated with 1:1 SBCS:DRG and 0.1 %(w/v) vanillin had potential use as edible film material for coating on climacteric fruits preservation.

Cross-linked poly(ester urethane)/starch composite films with high starch content as sustainable food-packaging materials: Influence of cross-link density

This study focused on the development of cross-linked poly(ester urethane)/starch (PEUST) composites containing 50 wt% starch content for food-packaging materials. The NCO-terminated poly(caprolactone-urethane) prepolymer (PCUP) was first synthesized through bulk condensation. Then, low-moisture starch (0.21 wt%) and PCUP-based PEUST films were fabricated through an intensive extrusion process, followed by thermo-compression molding. The chemical structure of PCUP and PEUST was confirmed using Fourier transform infrared spectroscopy. Moreover, a comprehensive evaluation was conducted to assess the influence of cross-link density on the physicochemical properties of the composite films. The results showed that an increase in the cross-link density within the composites improved component compatibility and tensile strength but reduced crystallinity, water sensitivity, hydrolytic degradability, and water vapor permeability (WVP) of the films. In addition, the cytotoxicity tests were conducted to evaluate the safety of the composite films, and the high cell viability demonstrated non-toxicity for food application. The PEUST-II films with moderate cross-link density exhibited a suitable degradation rate (27.7 % weight loss at degradation for 140 d), optimal tensile properties (tensile strength at break: 12.4 MPa; elongation at break: 352 %), and low WVP (68.4 g/(m2⋅24h) at 30 % relative humidity). These characteristics make them highly promising as fresh-keeping food packaging.

Biodegradable films from the lignocellulosic residue of switchgrass

Plastics thrown out as trash are an everlasting threat to our biosphere and ecosystem. A sustainable remedy within our reach is the use of agricultural biomass. Herein, the lignocellulosic residue of switchgrass biomass, extracted using alkaline and bleaching treatments and solubilized in ZnCl2 solution followed by crosslinking with calcium ions, is used to develop biodegradable films. The films have been characterized for color, transparency, thickness, moisture, water solubility, water absorption, water vapor permeability, tensile strength, elongation, and soil biodegradation. Mathematical modeling of the water absorption and biodegradation behavior have also been studied. The films are transparent, possess high tensile strength and low water vapor permeability, and biodegrade completely within 40 days at 30% soil moisture. The tensile strength and whiteness of films increase with CaCl2 concentration, but elongation, water absorption, water solubility, water vapor permeability, and biodegradation decrease. Overall, the strong and biodegradable switchgrass residue-based films open up a new window of opportunities to design and develop reusable, recyclable, and compostable films from underutilized, inexpensive, and abundant agricultural biomass contributing to the circular bioeconomy in a friendly and sustainable manner.

Effect of emulsifiers on the properties of corn starch films incorporated with Zanthoxylum bungeanum essential oil

The use of natural and safe ingredients in green food packaging material is a hot research topic. This study investigated the effect of different emulsifiers on starch film properties. Three types of emulsifiers, including Tween 80 as a small-molecule surfactant, sodium caseinate (CAS), whey protein isolate (WPI), and gelatin (GE) as macromolecule emulsifiers, whey protein isolate fibril (WPIF) as a particle emulsifier, were utilized to prepare Zanthoxylum bungeanum essential oil (ZBO) emulsions. The mechanical, physical, thermal, antibacterial properties, microstructure and essential oil release of starch films were investigated. CAS-ZBO nanoemulsion exhibited the smallest particle size of 198.6 ± 2.2 nm. The film properties changed with different emulsifiers. CAS-ZBO film showed the highest tensile strength value. CAS-ZBO and WPIF-ZBO films exhibited lower water vapor permeability than Tween-ZBO. CAS-ZBO film showed good dispersion of essential oil, the slowest release rate of essential oils in all food simulants, and the best antibacterial effect against Staphylococcus aureus and Listeria monocytogenes. The films composed of CAS-ZBO nanoemulsion, corn starch, and glycerol are considered more suitable for food packaging. This work indicated that natural macromolecule emulsifiers of CAS and WPIF are expected to be used in green food packaging material to offer better film properties.

Characterization of Sodium Alginate-Based Films Blended with Olive Leaf and Laurel Leaf Extracts Obtained by Ultrasound-Assisted Technology.

Due to environmental concerns, there is an increasing need to reduce the use of synthetic and non-renewable packaging materials to reduce waste and increase sustainability. This study aimed to characterise sodium alginate edible-based films (SA) incorporated with laurel leaf extract (LLE) and olive leaf extract (OLE) obtained by ultrasound-assisted extraction. Determination of total phenolic content, antioxidant, and antimicrobial activity was performed for the extracts and films. Also, thickness, tensile strength, elongation at break, modulus of elasticity, opacity and colour, moisture content, water vapour permeability (WVP), Fourier-transform infrared spectroscopy (FTIR) spectra, and surface morphology by scanning electron microscope (SEM) analyses were performed for the films. LLE yielded better results in terms of phenolic content (195 mg GAE/g), antioxidant (2.1 TE/g extract) and antimicrobial activity (MIC at 1% for Listeria monocytogenes and Staphylococcus aureus, and 1.8% for Enterococcus faecalis). For the films, the simultaneous incorporation of LLE 1% (w/v) and OLE 1% (w/v) resulted in a significant reduction of approximately 2 log CFU/g against S. aureus. The addition of LLE and OLE extracts also proved to improve barrier properties (lower WVP for SA films with LLE 1% + OLE 1%, 3.49 × 10-11 g m-1 s-1 Pa-1) and promoted changes in resistance and flexibility. The results demonstrated that active alginate-based films can be valuable for enhancing food preservation.

Effects of ZnO nanoparticles, polyethylene glycol 400, and polyoxyethylene sorbitan ester Tween 80 on PLA films properties

Abstract Polylactic acid has the potential to be an alternative to petroleum-based materials in the food packaging industry. In this study, the effect of zinc oxide nanoparticles, polyethylene glycol 400, and Tween 80 as plasticizers on the properties of polylactic acid films was investigated. In order to study the mechanical properties more accurately, the tests were repeated for four months. An experimental design method was used to investigate the effects of additives on the measurement factors and finally to choose the optimal combination with the help of the TOPSIS technique. The results showed that the addition of different materials increased the opacity, most of which being related to P400/ZnO (6.82 ± 0.07 mm−1). The presence of plasticizers increases the hydrophilicity of the film and the water vapor permeability. The highest contact angle (85.33° ± 4.00) and the lowest water vapor permeability (0.074 ± 0.002 g mm/kPa h m2) were related to neat PLA film. The lowest modulus of elasticity, the highest tensile strength and elongation at break were related to P400/T80/ZnO (1.18 ± 0.17 GPa, first month), PLA/ZnO (96.28 ± 3.17 MPa, fourth month), and P400/ZnO (76.82 ± 27.22 %, first month), respectively. The effect of plasticizers was significant in most of the measurement factors, but the effect of nanoparticles was significant in some cases such as opacity and contact angle. The results of an ANOVA analysis showed that the effect of film type on the mechanical properties was significant, and the effect of storage time was only significant on the elongation at break. According to the results obtained from the TOPSIS technique, P400/ZnO was chosen as the combination with the best features among the produced films.

Agro-Industrial Protein Waste and Co-Products Valorization for the Development of Bioplastics: Thermoprocessing and Characterization of Feather Keratin/Gliadin Blends.

Biopolymers based on plant and animal proteins are interesting alternatives in the development of films with future prospects as food packaging. Considering that in recent years there has been an increasing interest in the valorization of agro-industrial residues and by-products and that the blending of polymers can lead to materials with improved properties, in this work, keratin-rich feather fibers and gliadins were blended at different ratios in order to develop sustainable and biodegradable films. Control gliadin G100, feather F100 films, and their blends at 3:1 (G75F25), 2:2 (G50F50), and 1:3 (G25F75) ratios were successfully developed through thermoprocessing. The physical properties were differentiated as a function of the concentration of both polymeric matrices. Although gliadins showed higher hydrophilicity as confirmed by their highest swelling degree, films with high gliadin ratios exhibited lower water vapor permeability values at low and medium relative humidities. On the other hand, the feather fiber-based films displayed the highest Young's modulus values and provided an oxygen barrier to the blends, principally at the highest relative humidity. In conclusion, the blend of these protein-based polymers at different ratio resulted in interesting composites whose physical properties could be adjusted.

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.

Potential effect of citrate nanocellulose on barrier, sorption, thermal and mechanical properties of chitosan/Arabic gum packaging film

Currently, the necessity to diminish environmental pollution caused by petroleum-based packaging plastics has encouraged interest in creating renewable and biodegradable packaging polymers. The objective of this study is the development of a green nanocomposite constructed from citrate cellulose nanospheres (CNC) that have been embedded in (CH/AG) Chitosan/Arabic gum (CNC@CH/AG) to meet the mechanical requirements. Citrate CNC was prepared using a citric acid/HCl acid mixture and it is investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Zeta potential, and degree of substitution. CNC@CH/AG film was investigated by FTIR, XRD, scanning electron microscope (SEM), wettability, mechanical, barrier, water vapor sorption, and thermal characteristics. CNC@CH/AG film displayed declining in water vapor permeability. The lowest water vapor permeability (WVP) value was 0.044 ± 23 × 10−3 g. mm. kPa−1. h−1. m−2 compared with control (CH/AG) was 0.129 ± 81 × 10−3 up to 3 mg CNC. For sorption properties, the CNC@CH/AG nanocomposite films are consistent with the GAB model, Smith, Henderson, and Peleg models. In comparison to CH/AG, the addition of CNC enhances all of the nanocomposites' tensile strength and Young's modulus by nearly two and three times, respectively, with a decrease in elongation percentage. The addition of CNC renders CNC@CH/AG nanocomposite films more thermally stable and the total activation energy of CNC@CH/AG nanocomposite film (−94.97 J/mol) is more than three times that CH/AG film (−34.04 J/mole).

Enhancing plantain epicarp active edible coating performance through investigation of optimal spray coating conditions

The current research presents a comprehensive investigation aimed at predicting and optimizing the adhesion characteristics of Nanoemulsion coatings sprayed onto plantains epicarps. To achieve this, a full factorial experimental design and an artificial neural network model were deployed. The process parameters, consisting of the height of the nozzle, pressure, and time, served as inputs for the artificial neural network model, while the coating amount and thickness were measured and treated as targets for both models. Through meticulous training, the artificial neural network model demonstrated remarkable efficiency and reliability, evident in the high degree of coherence between predicted and experimental results (R² = 0.99 and MSE = 1.98 %). The study identified a critical sequence of variables (height/pressure/time: 0.15 m / 0.6 MPa / 5 s) that yielded optimal coating characteristics, including a thickness of 38.5 µm, permeance of 1.388 × 10–05 kg s−1 m−1 Pa−1, and water vapor permeability of 2.7 × 10–09 kg s−1 m−1 Pa−1, along with a contact angle of 11.3° indicative of enhanced wettability. Significantly, the coated epicarps exhibited lower water vapor permeability, implying an extended shelf life. This promising technology of edible coatings not only contributes to preserving fruit quality and prolonging shelf life for plantainss but also holds potential for application in other food products and fortifying food packaging practices. The current findings shed light on the valuable role of active edible coatings in advancing food preservation methods and sustainability within the food industry.

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.

Lightweight pumice mortars for repair of historic buildings –Assessment of physical parameters, engineering properties and durability

The subject of the presented research was an experimental analysis of physical, engineering and durability parameters of lightweight mortars intended for the repair of historical buildings. Compatibility criteria, the requirements of technical standards and guidelines, and last but not least, previously published research results dealing with the development of mortars for repair delicate historic structures were taken into account in the design of mortar composition. Crushed pumice of a similar grain size was used to lighten the reference lime-based mortar and natural hydraulic lime mortar with quartz filler. Replacement of quartz sand with pumice was 25, 50, 75 and 100% by volume. The use of pumice allowed the fundamental physical, mechanical, hygric, thermal and durability parameters of the lightweight mortars to be such that they met the standard requirements for repair mortars and the heritage conservation requirements for compatibility with the original materials of historic masonry. The main finding was the fact that by replacing sand with pumice, a significant increase in the porosity of the mortars was achieved, while maintaining sufficient mechanical strength due to the pozzolanic reaction of the pumice. Mortars based on natural hydraulic lime have become more resistant to frost and salt crystallization. The advantage of the developed mortars was their low thermal conductivity and high water vapor permeability, which made them suitable for use on damp masonry, which is a substantial scientific contribution of the manuscript.

Detailed investigation on the insulation and permeability characteristics of rigid polyurethane foam loaded with micron-sized Turkey feather powder depending on the free volume change

This study brokes new ground to understand the insulation and permeability performances of rigid polyurethane foams (RPUFs) containing the different contents of micron-sized turkey feather powders (TFPs) depending on the free volume change for the first time. The effects of TFPs loading on the RPUFs were investigated by the examination of their structural and chemical features (particle size and ATR-FTIR analyses), free volume property (PALS analysis), insulation features (thermal conductivity and sound absorption tests), permeability performance (air and water vapor permeability tests) and cellular topology (SEM). PALS analysis results revealed that the addition of TFPs into the foams led to the sharp decrease in all free volume parameters since TFPs caused the formation of the disordered cells by occupying the holes in the matrix. Furthermore, both thermal conductivity and acoustic performance of the resulting foams get worse when compared to unfilled RPUF. This results were attributed to the formation of thinner and weaker cells during polymerization, reduction in the amount of CO2 inside the cells, enhancement in the solid-phase level in the matrix due to the increasing of volumetric density. Additionally, the foam samples with high content of TFPs showed considerably lower air and water vapor permeabilities when compared to neat RPUFs due to the dominant hydrophobic character of the keratin and reduction in the degree of vacancies in the matrix. SEM analysis also revealed that TFPs showed good compatibility with RPUF, but the distorted and irregular shaped cellular morphology was obtained at high contents.

Alginate/guacamole edible films as moisture barrier layers in multicomponent foods

AbstractIn multicomponent foods having both moist and dry components (e.g., pizzas and tacos), moisture migration between components causes undesirable texture changes (e.g., loss of crispiness of the dry component). In this study, different proportions of alginate (film matrix), guacamole (hydrophobic component with sensory appeal), and glycerol (plasticizer) were combined to form edible films to be used as a moisture barrier between moist and dry components of multicomponent foods. Alginate was the component that most contributed to increase the film strength and to reduce its water vapor permeability (WVP). Guacamole, due to the presence of avocado lipids, enhanced the film hydrophobicity, although not having decreased the WVP (as expected), since it promoted discontinuities in the alginate structure. The film with the lowest WVP (containing an alginate/guacamole/glycerol dry mass ratio of 25/60/15) was inserted between nachos and tomato sauce, being able to reduce the crispiness loss of nachos during a 50‐min storage.

Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness

The present study was conducted with the aim of fabricating smart bilayer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata extract nanofibers (CMC-CNC and PLA-VOE) for freshness monitoring of Pacific white shrimps, minced lamb meat, chicken fillets, and rainbow trout fillets, during refrigerated storage conditions. The fabricated indicators based on CMC-PLA-VOE 5%, CMC-CNC 1%-PLA-VOE 5%, and CMC-CNC 3%-PLA-VOE 5% presented remarkable color changes in pH 1–12 buffer solutions, including red at pH 1–6, violet at pH 7–8, green at pH 9–10, and brown at pH 11–12. Significantly lower water vapor permeability and oxygen transmission rate of prepared polymers were found in comparison with the control groups (P < 0.05). Regarding the monitoring of food samples in real-time, the samples spoiled after 3 days, evidenced by total viable count, psychrotrophic bacterial count, total volatile basic nitrogen, and pH values of 7.17–7.54 log CFU/g, 5.68–6.23 log CFU/g, 25.14–28.12 mg N/100 g, and 7.10–7.66, respectively. Meanwhile, the noticeable color change of prepared indicators from white to violet (day 3) and finally dark violet (day 7) was observed, indicating a potential application in intelligent packaging for real-time control of the freshness of perishable food samples.

Preparation and characterization of self-standing biofilms from compatible pectin/starch blends: Effect of pectin structure

Pectin structure-miscibility-functionality relationships in starch films remain unknown. In this study, five citrus pectins (CPs) with 17 to 63 % of degree of methyl esterification (DM) and sugar beet pectin (SBP, rich in acetyl moieties and rhamnogalacturonan-I domains) were investigated for composition and structure and, further, blended with pea starch (3:1 starch-pectin weight ratio) to fabricate self-standing films. The incorporation of pectin resulted in a two- to three-fold increase in tensile strength and Young's modulus (up to 52.2 and 1837 MPa, respectively, using CP with low DM) without compromising elongation at break. Starch-SBP films presented the lowest strength among pectin films. Lower film moisture and water vapor permeability were attained with CP of high DM, or with SBP, whereas surface wettability was explained by counteracting factors affecting film compositional heterogeneity. Films made with high methoxyl CP, or with SBP, showed lower overall H-bonding (FTIR) and starch crystallinity (XRD). A DM above 57 % negatively affected the mixing and interfacial adhesion of pectin with starch, as shown by Attenuated Total Reflection-FTIR imaging. Pectins with the lowest purity, presumably with the greatest content in xyloglucan, as suggested by HPAEC, presented ~20 % higher elongation at break than the other films.

Hypophosphite cross-linked starch succinate/chitosan membranes as alternative for packaging and pharmaceutical application

The growing industrial demand for valuable biomaterials contributes to modifying readily available starch to give it the desired functional properties. The advantage of the reported studies was the modification of starch with succinic acid via sodium hypophosphite as a cross-linker. The cross-linked structure was confirmed with Raman, ATR-FTIR, 13C and 31P CP-MAS NMR spectroscopies. In the next step, the phosphonated starch succinate/chitosan materials were prepared for application in food packaging and coatings. The most desirable features for such employment were achieved, such as a low water vapour permeability through the membranes (~2 %) and accelerated biodegradability compared to starch film attributes. Significant differences in these properties resulting from the time of synthesis and the quantitative composition of the films were verified. The longer synthesis time of composites affected the better mechanical properties (Elongation at break, εb =~91–94 %, and Young's Modulus, E = 140‐160 MPa). Thermal parameters (including FTIR analysis of gaseous products evolved during the thermal decomposition) were confirmed. The changes in ordering behaviour (crystallinity degree, Xc) determined with XRD varied from 23 % (for the starch film) to 10–21 % (starch in composites). Obtained biodegradable starch-based materials may constitute an attractive ecological alternative for plastics.

Role of monomer sequence in the crystallization and rheology of PBAT

Poly(butylene adipate-ran-terephthalate) (PBAT) is a typical biodegradable aliphatic−aromatic polyester. It has been widely used as compost bags, packaging films, and agricultural mulching films because of its complete biodegradability, good processability and mechanical properties, and low water vapor permeability. In this work, we showed that a small difference in the monomer ratio of the BT (butylene terephthalate) and BA (butylene adipate) units of PBAT would lead to significant differences in the continuous sequential block distributions as determined by the high-resolution NMR tests and the first-order Markovian model. As a result, macroscopic properties, such as crystallization behaviors, phase separation behaviors, and rheology, are greatly affected. A PBAT sample with a higher BA content and, consequently, a longer continuous BA block sequence has a lower crystallization temperature, a weaker concentration fluctuation at elevated temperatures, and a stronger strain hardening in melt elongation.

Development of Plantago ovata seed mucilage and xanthan gum-based edible coating with prominent optical and barrier properties

This study investigates the fabrication of edible coating based on Plantago ovata seed mucilage (POSM). The films were prepared from POSM (1 %, w/v), glycerol (75 %, based on POSM mass), and xanthan gum (XG: 20, 30 and 40 %, based on POSM mass) by a casting method, and their physicochemical, mechanical, thermal, morphological, and barrier properties were determined. Results indicated the development of highly transparent (transparency values: 1.36 ± 0.05 to 2.42 ± 0.09) and hydrophobic films (contact angle: 101.57 ± 0.34 to107.08 ± 0.55o) with very low water vapor permeability (WVP: 2.77 ± 0.02 × 10−12 to 1.98 ± 0.04 × 10−12 g s−1m−1Pa−1), slight water solubility (31.14 ± 0.46 to 23.08 ± 0.82 %), and good mechanical properties (tensile strength: 30.87 ± 0.96 to 61.80 ± 0.71 MPa). Morphological studies also indicated smooth and uniform surfaces without pores and cracks. In addition, the films showed good antioxidant activity (61.46 to 68.71 %), and their antibacterial activity against E. coli, S. aureus and P. aeruginosa was also demonstrated. The applicability of the developed films to extend the shelf life of strawberries was shown by comparing the appearance of dip-coated strawberries and the control sample within 8 days at room temperature. Based on the results, the developed biofilms have great potential for edible coating and packaging applications.

Optimizing reaction condition of octenyl succinic anhydride on heat-moisture-treated sago starch and its application for biodegradable film

This study presented the impact of pH and octenyl succinic anhydride (OSA) concentration on the esterification reaction of heat-moisture-treated sago starch (HMT-S) using response surface methodology to achieve optimum degree of substitution (DS), reaction efficiency (RE), and water contact angle (CA). The results showed that HMT-OSA sago starch (HMT-OS) starch exhibited an optimum pH of 7.26 and an OSA concentration of 4.53%. The DS value, RE, and water CA of optimized HMT-OS starch were 0.0121, 33.07%, and 90.11°, respectively. Furthermore, the optimized HMT-OS was used to evaluate the effect of starch modification on film characteristics. HMT-OS film has the best moisture-proof and mechanical properties compared to control (NS), HMT-S, and N-OS films, as indicated by lower water vapor permeability (28.69 g H2O.mm/s.m2.Pa × 10-11), water solubility (26.61%), higher CA (104.40°), elongation at break (85.63%), and transparency (3.25% mm-1). According to the scanning electron micrographic images, the absence of cracks or pores was attributed to the waterproof properties and flexibility of the film. Conversely, x-ray diffraction results showed that the crystallinity of HMT-OS film decreased to 36.05%.