Myofibrillar Protein Films Research Articles

An intelligent myofibrillar protein film for monitoring fish freshness by recognizing differences in anthocyanin (Lycium ruthenicum)-induced color change

A novel smart film MP/BNC/ACN for real-time monitoring of fish freshness was developed using myofibrillar protein (MP) and bacterial nanocellulose (BNC) as film raw materials and anthocyanin (Lycium ruthenicum, ACN) as an indicator. Firstly, the film containing 1 % ACN (MP/BNC/ACN1) was found to have a moderate thickness (0.44 ± 0.01 mm) and superior mechanical properties (tensile strength (TS) = 8.53 ± 0.11 MPa; elongation at break (EB) = 24.85 ± 1.38 %) by determining the physical structure. The covalent, electrostatic, and hydrogen bonding interactions between anthocyanin and the film matrix were identified and confirmed by FT-IR spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) analysis. A comprehensive evaluation concluded that MP/BNC/ACN1 exhibited excellent trimethylamine (TMA) sensitivity (total color difference (ΔE), ΔETMA0-1000 = 4.47–31.05; limit of detection (LOD), LOD = 1.03) and UV stability (ΔE96h = 4.16 ± 0.13). The performance of the films in assessing fish freshness was evaluated, principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed that MP/BNC/ACN1 (ΔE2-10d = 16.84–32.05) could clearly distinguish between fresh (0–2 d), sub-fresh (4–6 d), and spoiled (8–10 d) stages of fish, which corresponded to the film colors of red, light red, and gray-black. In conclusion, this study addresses the limitation that intelligent films cannot visually discern real-time freshness during fish storage and provides a promising approach for real-time fish freshness monitoring.

Role of oil polarity on myofibrillar protein emulsions stability: A multi-scale research

The oil polarity was hypothesized to significantly influence the microscopic conformation of interfacial myofibrillar protein (MP) and thus the mesoscopic interfacial rheology of MP film, which ultimately tuned the macroscopic stability of MP-stabilized emulsions. In this research, the inner mechanism was revealed hierarchically based on emulsions multi-scale properties, by a combination of in vitro interfacial concentration measurement, dynamic interfacial tension measurement and interfacial dilatational rheology (highlighting Lissajous plots). Then, the above conclusion was verified through in silico molecular dynamic simulation. At macroscopic level, the light scattering results showed that emulsion prepared with higher polarity oil exhibited higher physical stability. This could be explained from the mesoscopic perspective that: (1) the adsorption dynamics of MP was faster (though lower diffusion rate, but higher penetration and rearrangement rate) on the higher polarity interface, which decreased interfacial tension more efficiently; (2) adsorption ratio, surface load and desorption ratio indicated that ‘multilayer interfacial film’ was formed by loosely-bound MP on the lower polarity interface, which decreased the effective interfacial coverage to impair emulsions stability; (3) Lissajous plots showed that interfacial structure with higher stability against large deformation was formed on the higher polarity oil interface. Finally, the microscopic molecular mechanism for explaining the above findings was revealed by in silico molecular dynamic simulation: though MP was less unfolded on the higher polarity interface leading to weaker intermolecular hydrophobic interactions, this compact molecular structure with stronger intramolecular rigidity predominantly contributed to steadier interfacial film structure. This multi-scale study provides a deep insight into the inner relationship between oil polarity and emulsions stability.

Preparation of mechanically strong and active composite films based on fish myofibrillar proteins: The dual effects of oxidized polyphenol crosslinking and layered double hydroxide reinforcement

To improve the properties of films prepared from silver carp muscle, a cross-linked nanocomposite antioxidant film based on myofibrillar protein (MP) was prepared using oxidized caffeic acid (OC), p-coumaric acid (OP), eriodictyol (OE) and naringenin (ON) as crosslinking agents in combination with layered double hydroxide (LDH). The structural, physical properties and antioxidant activity of the film were investigated. The examination of the changes in the side-chain groups of MP revealed that the addition of oxidized polyphenols decreased total sulfhydryl and free amino acid levels, showing a greater decrease in OC and OE with o-phenolic hydroxyl groups, whereas LDH showed no significant effect. Additionally, FTIR (Fourier transform infrared) and XRD (X-ray diffraction) confirmed the covalent or non-covalent interactions between oxidized polyphenols, LDH and MP, in which resulted in increased surface hydrophobicity of MP and a shift of the α-helical structure to random coils. This suggests that the protein underwent unfolding, which tends to induce intermolecular aggregation. Additionally, the microregional structure in the film became more compact. Moreover, the mechanical properties of MP-based films were significantly enhanced by the combination of oxidized polyphenols and LDH, especially the incorporation of OE and LDH resulted in a tensile strength reaching 17.4 MPa. Furthermore, the water vapor and oxygen permeability, surface hydrophobicity, UV barrier and thermal stability of MP-based films were also improved. Therefore, the dual effect of oxidized polyphenol cross-linking and LDH complex confers excellent free radical scavenging abilities and iron-reducing antioxidant functions to MP films.

Properties of fish myofibrillar protein film: effect of glycerol-sorbitol combinations.

The effects of glycerol-sorbitol combinations (G/S) at different ratios (0: 2, 0.5: 1.5, 1: 1, 1.5: 0.5, and 2: 0, w/w) on the properties of fish myofibrillar protein (FMP) films were evaluated and then compared to those of synthetic wrap film (polyvinyl chloride; PVC). The thickness of FMP films plasticized with G/S at various ratios was in the range of 0.012 to 0.013mm and transparency values were 3.81-3.86. Significant increases in elongation at break (65.81-116.53%), oxygen permeability (12.83-36.11 cm3/m2/day), and water vapour permeability (0.27-1.43 × 10-10g/m/s/Pa) were observed when the proportion of glycerol increased (P < 0.05). No significant difference was observed in a* and b* values, compared to the PVC film. However, tensile strength values (12.56-3.52MPa) decreased when the proportion of glycerol increased (P < 0.05). A change in the amount of sorbitol influenced the thermal properties of FMP films. According to their properties, up to 50% of glycerol could be substituted for sorbitol in order to enhance the strength, barrier, and thermal properties of the FMP films.

Decreased gelling properties of protein in mirror carp (Cyprinus carpio) are due to protein aggregation and structure deterioration when subjected to freeze-thaw cycles

The changes in the gelling property and structural integrity of mirror carp protein that was induced by freeze-thaw (F-T) cycles were discussed. The strength, whiteness and water-holding ability of myofibrillar protein (MP) gel, the solubility and Ca2+-ATPase activity of MP were all significantly reduced after 5 F-T cycles (P < 0.05). The transverse relaxation time peak (T2) of samples under repeated F-T cycles exhibited a significant redshift (P < 0.05). The MP film surface became rough and irregular, as observed using atomic force microscopy (AFM) during the multiple F-T cycles. Additionally, the state and the weight of molecular distribution evidenced that F-T cycles caused protein aggregation and mechanical damage. The alterations in primary, secondary and tertiary protein structure revealed that the protein structure integrity of fish was destroyed under repeated F-T cycles. These findings indicated that repeated F-T cycles should be avoided during the freezing storage of fish to improve gel quality and sustain protein structural integrity.

Study of the effect of the chitosan use on the properties of biodegradable films of myofibrillar proteins of fish residues using response surface methodology

Abstract This study aimed to determine the optimal formulation to prepare biodegradable myofibrillar protein films from fish residues, chitosan, and glycerol using the response surface methodology. The myofibrillar proteins (MP) were extracted from filleting residues of gilthead bream (Brachyplatystoma roussauxii). A full factorial design was employed to assess three independent variables (MP, chitosan, and plasticizer concentrations) and three dependent variables (tensile strength, elongation, and water vapor permeability). The experimental design results indicated the best conditions to prepare the film were 1.3% (m/v) MP, 30% (m/m) chitosan, and 40% glycerol (m/m). The control film was prepared with 1.3% (m/v) MP and 40% glycerol (m/m). Adding chitosan increased the viscosity of the solution and the elongation, but reduced solubility and swelling by 66,43% and 74,56%, respectively. The optimized film tended to have an opaque structure with excellent UV-barrier properties. It also had good thermal stability and dense structure, indicating chitosan is able to enhance the properties of fish myofibrillar protein films.

Improvement of fish protein films properties for food packaging through glow discharge plasma application

Myofibrillar proteins have good film forming ability, that leads to the formation of polymers with interesting properties for food packaging development. However, as other bio-sourced macromolecules, they have limited performance compared to synthetic materials and cold plasma represents a promising strategy to change polymer properties. Alternating current (AC) glow discharge plasma is a novel and innovative approach for surface modification of agro-based films in order to improve their properties. Then, the effects of exposure to AC glow discharge plasma were studied on the physicochemical, microstructural and thermal properties of myofibrillar protein films from fish. Films treated for 2 min showed increased elongation at break and decreased tensile strength, while the opposite behavior was observed after 5 min of treatment. Solubility in water increased with 5 min and water vapor permeability increased with 2 min of plasma treatment. Color and opacity also increased probably as a result of chemical changes because of plasma application. Slight changes were observed in microstructure of the films. Thermal properties results agreed with the modifications observed in physicochemical performance, which might be attributed to polymer surface functionalization and etching. Thus, the AC glow discharge is a promising alternative to other strategies in order to advance properties of myofibrillar protein films for food packaging because it is a dry process, does not cause damage by heating in the material, and does not pollute the environment.

Effects of plasticizers on the properties of fish myofibrillar protein film.

This study investigated the effects of various plasticizer types [glycerol (GLY), sorbitol (SOR), and polyethylene glycol (PEG)] on the properties of fish myofibrillar protein (FMP) film. FMP films plasticized with GLY showed the greatest elongation at break (116.53%). It also showed the greatest water vapor permeability (1.43 × 10-10gm-1s-1Pa-1). The film plasticized with SOR exhibited the highest tensile strength (12.56MPa) and film solubility (62.59%). PEG plasticized film showed to have yellowish colour as indicated by the high b* value and low light transmission at 280nm. Furthermore, FMP films containing PEG and SOR possessed lower moisture content than films with GLY. FT-IR and electrophoretic properties were not affected by any types of plasticizer. The appearance of the FMP film was similar to that of the PVC film. It was concluded that plasticizers had major effects on FMP films. They not only plasticize the protein film, but also affected other major film properties.

Characterization of fish myofibrillar protein film incorporated with catechin-Kradon extract

This study investigates the properties of films made from fish myofibrillar protein (FMP) incorporated with combinations of catechin-Kradon extract (C/K) (20%, w/w) at different ratios. The experimental films were compared to a polyvinyl chloride (PVC). The thickness and the transparency of the films were in the range of 0.014–0.015mm and 3.65–3.77, respectively. Significant decreases were observed in elongation at break (35–122%), water vapor permeability (0.54–1.26×10−10gm−1s−1Pa−1) properties, and a gradual decrease in L* value was pronounced when the proportions of catechins were increased (P<0.05). FMP films incorporated with C/K demonstrated to have very good barrier properties to UV light and also enhanced the thermal stability of the developed FMP films. All film samples had a smooth surface; however coarser surfaces were observed when the amounts of catechins were increased. Furthermore, the developed FMP films showed high antioxidant capability. However, no significant antimicrobial activity was observed in this film. It is determined that FMP films enriched with C/K can be used for food packaging, with particular potential for active packaging. However, as compared with the PVC, the FMP films need further development, especially in terms of their mechanical and water barrier properties.

Properties of fish myofibrillar protein film incorporated with catechin-Kradon extract

Abstract Properties of fish myofibrillar protein (FMP) films incorporated with catechin-Kradon extract (Careya sphaerica Roxb.) (CK) were investigated. The incorporation less than 9 mg/ml of CK improved tensile strength, but this slightly declined when increasing the concentration (P

The effects of microbial transglutaminase on the properties of fish myofibrillar protein film

In this study, the effects of microbial transglutaminase (MTGase) on the properties of fish myofibrillar protein (FMP) films were investigated. As MTGase content increased, the thickness and tensile strength of the FMP films increased. In contrast, their elongation at break (167.49–85.61%), film transparency, water vapor permeability (2.38–2.02 × 10−9 g m−1 s−1 Pa−1), moisture content, film solubility, and degree of swelling all decreased (P < 0.05). Lightness also decreased, and yellowness increased as MTGase content was increased (P < 0.05). MTGase action also significantly improved barrier properties and thermal stability of films. Electrophoretic and FT-IR studies revealed that cross-linking and conformational changes were pronounced in film treated with MTGase. Based on these results, the addition of MTGase produced a good alternative method for improving FMP film properties; however, the mechanical and water barrier properties of the resulting films need further development.

Shelf life extension for Bluefin tuna slices (Thunnus thynnus) wrapped with myofibrillar protein film incorporated with catechin-Kradon extract

This study investigated and determined the changes in various qualities of Bluefin tuna (Thunnus thynnus) slices that were wrapped with fish myofibrillar protein films (FMP) and stored in a refrigerator (4 ± 1 °C) for 10 days. The films were incorporated with catechin-Kradon extract (Careya sphaerica Roxb.). It was found that decreases in the redness index for the tuna slices were coincidental with increases in metmyoglobin content. Especially rapidly changes were observed in the control without wrapping. Changes in the total volatile base nitrogen, peroxide value, and TBARS were markedly observed in the samples wrapped with FMP when compared with others (P < 0.05). Slices of tuna flesh wrapped with FMP showed to have the lowest growth of psychrophilic bacteria when compared to those wrapped with the control film (LDPE) and the control sample without wrapping (P < 0.05). However, the pH of all samples fluctuated between 5.43 and 5.66 throughout the duration of storage. Increases in weight loss and hardness values were observed in all samples (P > 0.05). Sensory evaluation showed that the tuna wrapped with FMP had the longest shelf life (8 days), in contrast to the control without wrapping (2 days) (P < 0.05). Successful inhibition of microbial growth and lipid oxidation in the tuna slices was possible with FMP. Therefore, fish myofibrillar protein film incorporated with catechin-Kradon extract showed to have a beneficial effect on the quality of fresh tuna slice for the purposes of prolonging shelf life.

Phenolics-protein interaction involved in silver carp myofibrilliar protein films with hydrolysable and condensed tannins

Silver carp myofibrillar protein films were prepared with tannins (tannic acid and apple procyanidins) at various concentrations (30 and 50 g/kg protein) under alkaline and heating condition. Phenolics-protein interaction as well as related properties of incorporated film was evaluated. Available amino and total sulfhydryl groups in film-forming solution (FFS) were decreased especially by tannic acid, whereas protein solubilities in the film were more sharply reduced by apple procyanidin. SDS-PAGE pattern suggested that non-sulfide covalent bonds were formed between tannins and protein molecules, and more protein polymerization was induced by apple procyanidin. On the other hand, the incorporation of tannic acid and apple procyanidin led to an increased tensile strength (TS) with accompanying decreases in elongation at break (EBA) and water vapor permeability (WVP). The film with apple procyanidin had higher TS and EBA as well as lower WVP than that with tannic acid. Tannins especially condense tannin could covalently crosslink with protein molecules to form protein-phenolics- protein polymers, and thus improve some physicochemical properties of the resulting protein films.

Effect of protein concentrations on the properties of fish myofibrillar protein based film compared with PVC film.

The effect of protein concentrations on the properties of fish myofibrillar protein film (FMP) were investigated and compared with commercial wrap film (polyvinyl chloride; PVC). FMP (2%, w/v) showed the highest mechanical properties [tensile strength: 4.38MPa and elongation at break: 133.05%], and water vapor permeability [2.81×10(-10)gm(-1)s(-1)Pa(-1)]. FMP contained high molecular weight cross-links, resulting in complex film network, as indicated by lower film solubility (19-22%) and protein solubility (0.6-1.3%). FMP showed excellent barrier properties to UV light at the wavelength of 200-280nm. FMP had the thickness [0.007-0.032mm], color attributes and transparency similar to PVC film [thickness: 0.010mm]. Therefore, protein concentration majority influenced the properties of develop FMP. The protein content of 1% (w/v) had potential to be developed the biodegradable film with comparable properties to the commercial wrap film.

Potential use of gelatin hydrolysate as plasticizer in fish myofibrillar protein film

The effect of fish gelatin hydrolysates having different degree of hydrolysis (DH: 23, 61 and 95%) as plasticizer at various levels (30–60%) in fish myofibrillar protein (FMP) film was investigated, in comparison with glycerol. Regardless of DH, FMP films incorporated with gelatin hydrolysates at 50 and 60% of FMP generally had higher elastic modulus (E) and tensile strength (TS) but lower water vapour permeability (WVP), compared with those added with glycerol at the same level (p < 0.05). At the same DH, both E and TS of film decreased, while elongation at break (EAB) and WVP increased with increasing levels of gelatin hydrolysate (p < 0.05). When gelatin hydrolysate at the same level (30, 40, 50 or 60%) was used, the decreases in TS and E but the increases in WVP were found as DH increased. Nevertheless, FMP film added with gelatin hydrolysate exhibited the higher b* value, compared to film containing glycerol (p < 0.05). Thus, gelatin hydrolysate could be potentially used as a plasticizer in FMP film and its plasticizing effect was governed by DH and levels used.

Effect of pH on the preparation of edible films based on fish myofibrillar proteins

ABSTRACT: Transparent and flexible edible/biodegradable films were successfully made from myofibrillar proteins of blue marlin meat. The effect of pH of film-forming solutions on film formation, tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP), light transmission, transparency, film solubility, protein solubility and enzymatic hydrolysis was investigated. Myofibrillar protein-based films were formed within pH 2–3 and 7–12, whereas films were not formed between pH 4 and 6 because of the poor protein dispersion around the isoelectric point. TS of the films was higher when prepared at the acidic (pH 2, 3) and alkaline (pH 11, 12) conditions, whereas EAB was almost constant irrespective of pH. On the whole, the pH of film-forming solutions had no effect on WVP, light transmission, film solubility and enzymatic hydrolysis. WVP of myofibrillar protein films were slightly lower than those of other protein-based edible films and higher by one to three orders of magnitude than those of synthetic films. The films prepared at lower or higher pH, which had a more stable protein network, possessed superior transparency close to synthetic films.

Glass Transition Study of Nile Tilapia Myofibrillar Protein Films Plasticized by Glycerin and Water

Studies on glass transition of myofibrillar proteins based edible films are scarce. This work aimed to determine the T g of edible films from Nile Tilapia myofibrillar proteins as a function of water content. Films with 30 or 70 g of glycerol/100 g of protein and several water content, were analyzed with a DSC TA 2010. Samples conditioned at water activity between 0.11 and 0.75, clearly showed one glass transition at low temperatures (<223 K), and another transition, less visible, above 273 K. DSC curves of samples conditioned ata w=0.84, also showed an endothermic peak below 273 K. These results rendered evidence of phase separation within edible films.

Influence of Relative Humidity and Film Composition on Oxygen and Carbon Dioxide Permeabilities of Edible Films

At low relative humidity (RH), an edible wheat gluten film presents very low oxygen and carbon dioxide permeabilities [1.24 and 7.4 amol/(Pa m s), respectively, at 25 °C]. For higher than 60% RH, O2 and CO2 permeabilities increase exponentially [to 1290 and 36 700 amol/(Pa m s), respectively, at 95% RH], presumably due to the plasticizing effect of water molecules. Pectin, chitosan, pullulan, and myofibrillar protein films are also very permeable to O2 and CO2 at high RH. The selectivity ratio (CO2/O2 permeability) of all films tested at high RH was very high (from 10 to 28) as compared to conventional synthetic films (4 to 6). Keywords: Edible film; gas permeability; relative humidity