Propriedades físicas, mecânicas e ópticas de filmes à base de amido incorporados com extrato rico em fenólicos de bagaço de Spondias purpurea L.

Effect of glycerol and amylose enrichment on cassava starch film properties

The amyloid fibril-stabilized Pickering emulsion significantly enhances the mechanical and barrier properties of Konjac Glucomannan active films for cherry preservation.

In this study, films from cassava starch and rosemary oil were prepared by using the casting method. Glycerol was used as plasticizer and tween 80 as surfactant. The influence of Cassava starch (Cs), Rosemary oil (Ro), Surfactant (Sf) concentrations and Thickness of film (Tf) on the mechanical, optical, and barrier properties of cassava starch films was studied applying the Response Surface Methodology. The response variables were optimized by using second order polynomial models with satisfactory fit and coefficient of determination (R2) values (> 81%). The optimized conditions with the goal of maximizing mechanical properties and minimizing barrier and optical properties and desirability function (0.9796) were Cs = 3 g/100 g solution, Ro = 4 g/100 g Cs, Sf = 69 g/100 g Ro and Tf = 0.05 ± 0.001 mm. The films produced under these conditions displayed high mechanical strength (16.7 MPa), young´s modulus (2911.4 MPa), low elongation at break (0.2%), low water vapor transmission (0.8 × 10−14 g/Pa s m), low solubility (33.24%), and low opacity (16%). These results provided good mechanical, barrier, and optical properties, compared to films based on other starch resources.

High pressure homogenization of mechanically deboned chicken meat protein suspensions to improve mechanical and barrier properties of edible films

In the present study, flaxseed protein-alginate films were prepared with different concentrations of silver nanoparticles (AgNPs) and were evaluated for the physicochemical, mechanical, barrier, and thermal properties. The presence of AgNPs in the protein-alginate films significantly affected the properties of films. Film thickness and moisture content increased proportionally with an increase in the concentration of AgNPs; however, the solubility was decreased. A decrease in L* value and an increase in a* and b* values, along with an increase in total color change was observed with the addition of AgNPs. The mechanical properties of films were improved with the addition of AgNPs, as indicated by the results of tensile strength and percentage elongation. Water vapor permeability was reduced, which showed the improvement in barrier properties of films. Differential scanning calorimetry and thermal gravimetric analysis results indicated improvement in the thermal stability of AgNPs incorporated flaxseed-alginate films. The study on the influence of AgNPs on bacterial inactivation showed that, compared to the control film, all films integrated with silver nanoparticles had strong antibacterial action. The inhibition zones obtained at various AgNP concentrations revealed that the antibacterial activity of AgNPs against Gram-negative (E. coli) bacteria was greater than that of Gram-positive (S. aureus) bacteria. Therefore, silver nanoparticles incorporated flaxseed protein-alginate films have the potential to be used as an antimicrobial food packaging film.

ABSTRACTThe poor barrier and mechanical properties of biopolymer‐based food packaging can potentially be enhanced by the use of layered silicates (nanoclay) to produce nanocomposites. In this study, starch‐clay nanocomposites were synthesized by a melt extrusion method. Natural (MMT) and organically modified (I30E) montmorillonite clays were chosen for the nanocomposite preparation. The structures of the hybrids were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Films were made through casting using granulate produced by a twin‐screw extruder. Starch/MMT composite films showed higher tensile strength and better water vapor barrier properties than films from starch/I30E composites, as well as pristine starch, due to formation of intercalated nanostructure. To find the best combinations of raw materials, the effects of clay content (0–21 wt% MMT), starch sources (corn, wheat, and potato), and amylose content (≈0, 28, 55, 70, 100%) on barrier and mechanical properties of the nanocomposite films were investigated. With increase in clay content, significantly higher (15–92%) tensile strength (TS), and lower (22–67%) water vapor permeability (WVP) were obtained. The barrier and mechanical properties of nanocomposite films did not vary significantly with different starch sources. Nanocomposite films from regular corn starch had better barrier and mechanical properties than either high amylopectin or high‐amylose‐based nanocomposite films. WVP, TS, and elongation at break (%E) of the films did not change significantly as amylose content increased beyond 50%.

Films of 0.11 to 0.13 mm thickness were prepared using gelatins from the skins of cultured freshwater carp species and mammalian gelatins viz., porcine and bovine skin gelatin. A comparative study was made on the physical, mechanical, and barrier properties of these films. The amino acid composition, gel strength, clarity, and gel setting point of the gelatins were also determined. Carp skin gelatins had a lower imino acid content (19.16% to 20.86%) than mammalian skin gelatins (22.91% to 23.7%). Grass carp gelatin had gel strength of 230.2 B that is comparable to the reported value for bovine skin gelatin (227.2 B). The bloom values of rohu and common carp skin gelatins were 188.6 B and 181.3 B, respectively, which were significantly lower than mammalian gelatins. Mammalian gels have significantly higher (P < 0.05) setting temperatures (23.7 to 24.2 °C) than carp skin gelatins. Tensile strength (TS) was lowest for films from common carp and rohu skin gelatin (490 and 497 kg/cm(2), respectively) and highest for porcine skin gelatin film. The degree of transparency (L*) was significantly higher for films from grass carp, bovine hide, and pork skin gelatin films. Carp skin gelatin films had significantly lower water vapor permeability (WVP) and oxygen permeability (OP) than mammalian skin gelatin films, which indicated that carp skin gelatin based films have superior barrier properties than mammalian skin gelatin films.

The mechanical (tensile strength, elongation at break, mechanical work of deformation) and barrier (water vapor permeability and water vapor uptake) properties of chitosan films produced with acetic and lactic acids have been studied as a function of storage time, molecular weight of chitosans, concentration of plasticiser and the storage temperature. It was demonstrated that mechanical properties of chitosan-based films can be improved to a great extent during storage at low temperatures in freezer and refrigerator. Transition of chitosan molecules during storage in the solid state to more extended conformations and free volume changes are considered as mechanisms for the improvement of mechanical and barrier properties of chitosan films. The best mechanical properties are achieved for chitosan films produced with acetic acid and plasticized by the addition of 20% of glycerol. Sharp decrease in water vapor permeability has been demonstrated for thinner chitosan films and related to more dense packing and orientation of linear chitosan macromolecules.

Chia (Salvia hispanica L.) flour seeds produce films with good barrier properties against water vapor and could be used as food packaging; however, their mechanical properties are poor, which limits their application. The incorporation of nanoparticles into natural polymers is a strategy used to improve the properties of films to increase their applications. Furthermore, nanoparticles can encapsulate antioxidant agents and generate active films. The objective of this study was to evaluate the influence of chia flour (4%–7%), glycerol (15%–25%), and chia extract-loaded chitosan nanoparticles (ChCNp) (0%–0.75%) on the physical, mechanical, barrier, structural and antioxidant properties of chia flour nanocomposite films. Chitosan nanoparticles loaded with antioxidant chia extract were synthesized by ionic gelation and incorporated into the films. The thickness, water vapor permeability, tensile strength, and antioxidant properties of the films were evaluated using a Box-Behnken experimental design. Structural analysis was conducted using the FTIR technique. The results of the ANOVA of the responses were adjusted to second and third order polynomial models obtaining determination coefficients of 0.96–0.99. The water vapor permeability of the films was 3.89 × 10-8–1.68 × 10−7 g mm/Pa s m2, tensile strength was 0.67–3.59 MPa and antioxidant activity was 57.12%–67.84%. The variables presented different effects on the films. Increasing the chia seed flour concentration negatively affected the water vapor permeability but improved the tensile strength and the antioxidant capacity of the films. The increase in glycerol concentration caused the films to become brittle. The nanoparticles had a significant effect on the thickness of the films and improved their mechanical and antioxidant properties. However, they did not show an effect on barrier properties. The results demonstrate that it is possible to obtain nanocomposite films with antioxidant capacity from chia seed flour and with the incorporation of chitosan nanoparticles loaded with antioxidants.

Effect of metakaolin content on mechanical and water barrier properties of cassava starch films

Response surface modeling and analysis of barrier and optical properties of maize starch edible films

Farm-raised catfish are important to the economy of the southeastern states in the United States, and catfish processing produces about 55% of by-products for inexpensive sale. Therefore, the utilization of catfish by-products is of great interest to the catfish industry. The objectives of this research were to determine the optimum pretreatment method to extract catfish gelatin for edible film application, and to characterize physical, mechanical, and barrier properties of edible films fabricated with catfish skin gelatin. Catfish skins obtained from a local plant were treated with 6 selected pretreatment methods. The main extraction was performed with deionized water at 50 degrees C after pretreatment. The gelatin yield was calculated and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize molecular weight (MW) profile. Color, tensile strength (TS), elongation, and water barrier property were determined to characterize the fabricated catfish gelatin films. From the results of gelatin yield, color, SDS-PAGE, as well as mechanical and barrier properties of the film, the pretreatment method with 0.25 M NaOH and 0.09 M acetic acid, followed by extraction at 50 degrees C for 3 h, was determined as the optimum extraction method. The catfish gelatin exhibited higher MW fractions than commercial mammalian gelatin. The catfish gelatin extracts possessed film-forming properties determined by TS, elongation, and water vapor permeability (WVP) comparable to those of commercial mammalian gelatin. The selected formula for catfish gelatin film was determined as 1% gelatin and 20% glycerol, resulting in greatest TS and lowest WVP.

Development and characterization of pomegranate peel extract-infused carboxymethyl cellulose composite films for functional, sustainable food packaging

Effect of beetroot (Beta vulgaris L. var conditiva) fiber filler and corona treatment on cassava starch films properties

Effects of nano-kaolin incorporation into semolina films on the physical, mechanical, thermal, barrier and antimicrobial properties of the resulting bio-nanocomposite films were investigated. The properties included crystal structure (by X-ray diffraction), mechanical resistance, color, Fourier transform infrared spectra, decomposition temperature, water-vapor permeability (WVP), oxygen permeability (OP), and antimicrobial activity against Staphylococcus aureus and Escherichia coli. Kaolin was incorporated into biofilms at various amounts (1, 2, 3, 4, and 5%, w/w total solid). All films were plasticized with 50% (w/w total solid) combination of sorbitol/glycerol at 3:1 ratio. The incorporation of nanokaolin into semolina films decreased OP and WVP. The moisture content and water solubility of the films were found to decrease by nanokaolin reinforcement, and mechanical properties of films were improved by increasing nanokaolin concentration. Tensile strength and Young's modulus increased from 3.41 to 5.44MPa and from 63.12 to 136.18, respectively, and elongation-at-break decreased. The films did not exhibit UV absorption. In conclusion, nanokaolin incorporation enhanced the barrier and mechanical properties of semolina films, indicating the potential application of these bio-nanocomposites in food-product packaging.