Development and characterization of fish myofibrillar protein/chitosan/rosemary extract composite edible films and the improvement of lipid oxidation stability during the grass carp fillets storage

Chitosan/teff flour active films incorporated with citric acid and beetroot leaf extract: Physicochemical properties and mathematical modeling of phenolic release

Active compounds are integrated into food packaging films to enhance their food protection capabilities. Understanding the release of these components in films, particularly in crosslinking scenarios, is crucial. This study aimed to mathematically model the release of phenolic compounds from chitosan/teff flour films to understand how active compounds gradually release. Moreover, it was aimed to study the effects of incorporation of beetroot leaf extract and citric acid crosslinking. The collective observations, encompassing increased density and thermal stability, alongside concurrent reductions in moisture content, water solubility, water vapor permeability and swelling index following citric acid addition, strongly suggested the presence of crosslinking. Applying Fick's law and the finite element method revealed a substantial influence of the crosslinking agent on diffusion coefficients. The model exhibited strong agreement with experimental data, as reflected in low root mean square error values ranging from 3.02 to 8.50 mmol/m3 for films. Furthermore, the influence of citric acid crosslinking on the release of TPC was evident, as indicated by a decrease in average diffusion coefficient values from 3.499 × 10-13 m2 s-1 to 1.770 × 10-13 m2 s-1 with the formula with 1.5 % citric acid and 0.5 % beetroot leaf extract. This showcases the impact of various parameters on controlled release in food packaging.

Gelatin/dextran active films incorporated with cinnamaldehyde and α-tocopherol for scallop (Patinopecten yessoensis) adductor muscle preservation

Scallops are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid but perishable due to their microbial growth and lipid oxidation. In this study, gelatin/dextran films containing cinnamaldehyde and α-tocopherol (0% + 0%, 0.3% + 0.3%, 0.6% + 0.6%, 0.9% + 0.9%, and 1.2% + 1.2%, w/w) as active fillers were developed by solution casting method, and their preservation effects on scallop adductor muscle refrigerated at 4°C for 0, 3, 6, 9, and 12 days were evaluated. Inclusion of the two active fillers did not influence the thermal stability of the films but created heterogenous and discontinuous film microstructure and increased the film hydrophobicity. Increase in the concentrations of active fillers lowered the mechanical properties and water vapor permeability of the films but increased their crystallinity, thickness, water contact angle, opacity, antibacterial property, and antioxidant property. The longest release times for both cinnamaldehyde and α-tocopherol were found in 95% (v/v) ethanol solution. The gelatin/dextran films containing 1.2% (w/w) of active fillers (Gelatin [Ge]/Dextran [Dx]/1.2 film) improved the chemical stability of refrigerated scallop adductor muscle. The total viable count (TVC) of the unpackaged scallop adductor muscle exceeded the recommended limit of 7 lg CFU/g on day 6 (7.07 ± 0.50 lg CFU/g), whereas the TVC of the Ge/Dx/1.2 film-packaged scallop adductor muscle was still below the limit on day 9 (5.60 ± 0.50 lg CFU/g). Thus, the Ge/Dx/1.2 film can extend the shelf life of refrigerated scallop adductor muscle by at least 3 days. Overall, the developed gelatin/dextran active packaging films are promising for the preservation of aquatic food products.

Influence of Curcuma Longa extract in citral addition on functional properties of thin films with triple-layer structure based on furcellaran and gelatin

In this study, we obtained triple-layer films based on furcellaran and gelatin, in which the middle layer was enriched with extract of Curcuma longa in citral. This newly developed material underwent a comprehensive characterisation process to identify significant improvements in its functional properties. Both SEM, XRD and FTIR analyzes indicated the formation of interactions not only between the components but also between the film layers. Notably, the incorporation of the natural extract led to a significant reduction in solubility, decreasing it from 74.79 % to 57.25 %, while enhancing thermal stability expressed as a melting point elevating it from 147.10 °C in the control film to 158.80 °C in the film with the highest concentration of the active ingredient. Simultaneously, the addition of this active ingredient resulted in decreased water contact angle (WCA) values, rendering the film more hydrophilic. The produced films exhibit great promise as packaging materials, particularly within the food industry, and the conducted research is marked by its forward-looking and developmental approach.

Enhancing the bioavailability and antioxidant activity of natamycin E235-ferulic acid loaded polyethylene glycol/carboxy methyl cellulose films as anti-microbial packaging for food application

This study investigated the development of biodegradable films made from a combination of polyethylene glycol (PEG), carboxymethyl cellulose (CMC) and mixtures from natamycin and ferulic acid. The films were characterized for their surface microstructure, antioxidant activity, thermal stability, mechanical properties, permeability and antifungal/bacterial activity. The addition of natamycin and ferulic acid to the film matrix enhanced antioxidant activity, thermal stability, antimicrobial activity, reduced the water vapor permeability (WVP) to 1.083 × 10-10 g × m-1s-1Pa-1, imparted opaque color and increased opacity up to 3.131 A mm-1. The attendance of natamycin and ferulic acid inside films created a clear roughness shape with agglomerates on the surface of films and caused a clear inhibition zone for Aspergillus niger, E. coli and C. botulinum. The utilization of PG/CMC/N-F packaging material on Ras cheese had a noticeable effect, resulting in a slight decrease in moisture content from 34.23 to 29.17 %. Additionally, it helped maintain the titrable acidity within the range of 0.99 % to 1.11 % and the force required for puncture from 0.035 to 0.052 N with non-significant differences. Importantly, these changes did not significantly affect the sensory qualities of Ras cheese during the storage period.

Enhancing the lipid stability of foods of animal origin using edible packaging systems

Foods of animal origin are prone to oxidation due to their high lipid content and fatty acid profile. Edible packaging systems have evolved as a new way of preserving animal-derived foods and have been reported to retard lipid oxidation using antioxidant molecules from side-streams, waste, and agricultural by-products. Studies have evaluated previously undocumented film materials and novel bioactive molecules as additives for edible packaging for animal-derived foods. However, none of the studies is specifically focused on evaluating the packaging systems available for enhancing lipid stability. This paper thoroughly examines and discusses the application of edible packaging containing novel antioxidant molecules for controlling the lipid oxidation of animal-derived foods. The paper analyses and interprets the main findings of the recently published research papers. The materials and active principles used for enhancing lipid stability have been summarised and the underlying mechanisms discussed in detail. Studies should aim at using cheaper and readily available natural ingredients in future for the production of affordable packaging systems.

Determination of Biogenic Amine Level Variations upon Storage, in Chicken Breast Coated with Edible Protective Film

A new chitosan-based protective film containing rosemarinic acid (0.282% w/w) has been elaborated. The film was formed from a water-oil emulsion system and applied to poultry meat samples using a dip-coating technique. Various physicochemical parameters of the coatings, such as thickness, Young's modulus, elongation at break, water vapor transmission rates, and antioxidant activity, were tested with free-standing film samples peeled from a Petri dish. Compared to neat chitosan films obtained similarly, new films cast from the emulsion showed significantly better elasticity (Young's modulus was diminished from 1458 MPa to about 29 MPa). Additionally, barrier properties for moisture transition decreased from 7.3 to 5.8 g mm m-2 day-1 kPa-1. The coated poultry samples were subsequently evaluated in juxtaposition with uncoated ones in a storage test. Levels of selected biogenic amines (histamine, tyramine, tryptamine, phenylethylamine, putrescine, cadaverine, spermine, and spermidine), total bacterial count, and lipid oxidation levels in the meat samples were analyzed during storage at 4 °C (up to 96 h). The results obtained for the biogenic amines, total bacterial content, calculated biogenic amine index, and the ratio of spermidine to spermine in meat samples suggest the advantage of the proposed coatings with rosmarinic acid in protecting poultry meat against environmental factors and rapid spoilage.

Preparation and properties of films loaded with cellulose nanocrystals stabilized Thymus vulgaris essential oil Pickering emulsion based on modified tapioca starch/polyvinyl alcohol

Pickering emulsions were prepared by stabilizing thymus vulgaris essential oil (TEVO) with cellulose nanocrystals (CNCs), which formed composite films by loading the emulsions into modified tapioca/polyvinyl alcohol (PVA)-based films. The results showed that the 1.0 % CNCs-15 % TEVO emulsion had optimal stability and smaller particle size. The emulsion increased the thickness of the composite film in the form of solid material additions (thickness, 0.062-0.099 mm), which opacity given the laminating film's superior UV-blocking ability compared to blank film. The emulsion plasticizing effect enhanced the film's elongation at break (EAB, 123-159 %). In addition, due to the hydrophobicity and influencing the diffusion path of water molecules in the emulsion, the denser microstructure composite film had a lower water vapor transmission coefficient (WVP, 6.22 × 10-11-5.35 × 10-11g∙cm/cm2∙s∙Pa) to impede moisture penetration. Meanwhile, the composite film can effectively maintain the color and inhibit the growth of microorganisms to extend the storage time of fish fillets.

Effects of Gas Composition on the Lipid Oxidation and Fatty Acid Concentration of Tilapia Fillets Treated with In-Package Atmospheric Cold Plasma

Cold plasma (CP) is a non-thermal preservation technology that has been successfully used to decontaminate and extend the shelf life of aquatic products. However, the preservation effect of CP treatment is determined by several factors, including voltage, time, and gas compositions. Therefore, this study aimed to investigate the effects of gas composition (GasA: 10% O2, 50% N2, 40% CO2; GasB: air; GasC: 30% O2, 30% N2, 40% CO2) on the lipid oxidation of tilapia fillets treated after CP treatment. Changes in the lipid oxidation values, the percentages of fatty acids, and sensory scores were studied during 8 d of refrigerator storage. The results showed that the CP treatment significantly increased all the primary and secondary lipid oxidation values measured in this study, as well as the percentages of saturated fatty acids, but decreased the percentages of unsaturated fatty acids, especially polyunsaturated fatty acids. The lipid oxidation values were significantly increased in the GasC-CP group. After 8 d, clearly increased percentages of saturated fatty acids, a low level of major polyunsaturated fatty acids (especially linoleic (C18:2n-6)), and a decrease in the percentages of eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) were found in GasC-CP; that is, the serious oxidation of lipids was found in the high O2 concentration group. In addition, the sensory score was also lower than that of the hypoxia CP group. Therefore, high O2 concentrations can enhance lipid oxidation and the changes in the fatty acid concentration. Controlling the O2 concentration is reasonable to limit the degree to which lipids are oxidized in tilapia after the in-package CP treatment.

Enhanced physical properties, antioxidant and antibacterial activity of bio-composite films composed from carboxymethyl cellulose and polyvinyl alcohol incorporated with broccoli sprout seed extract for butter packaging

This study investigated the development of biodegradable films made from a combination of carboxymethyl cellulose (CMC), Polyvinyl alcohol (PVA), and purified extract of broccoli sprout seed (BSSE). The films were characterized for their color, physical properties, surface morphology, crystallinity, mechanical properties, and thermal properties. The addition of BSSE up to 1.4 % to the film matrix imparted opaque color and increased opacity up to 3.652. The films also became less moisture-absorbent 8.21 %, soluble 19.16 %, and permeable to water vapor 1.531 (× 10-10 g.m-1 s-1 pa-1). By utilizing 0.7 % from BSSE inside films, the surface of the films became smoother but became rough with higher concentrations 2.1 % of BSSE. Fourier transform infrared (FT-IR) analysis showed that there was physical interaction between the BSSE extract and the PV/CM matrix. The films showed good thermal stability, and the incorporation of BSSE improved their ability to preserve the acidity, TBARS, peroxide value, and total color differences of butter during cold storage.

Crosslinked fish scale gelatin/alginate dialdehyde functional films incorporated with carbon dots derived from pomelo peel waste for active food packaging

A multifunctional and environmentally friendly composite film was developed by incorporating pomelo peel-derived carbon dots (PCDs) into a fish scale gelatin (FSG)/alginate dialdehyde (ADA) biopolymer matrix. ADA was used to reinforce the physicomechanical properties of the FSG film via Schiff base crosslinking. PCDs with strong antioxidant and antimicrobial activities were synthesized via a hydrothermal method. The effect of various PCDs content on the surface morphological, physicochemical, and functional characteristics of the composite films was investigated. The results showed that the introduction of PCDs into the FSG/ADA matrix effectively reinforced the mechanical performance, enhanced the water vapor and water resistance, increased UV-light blocking, conferred fluorescence properties, and improved the thermal properties of the composite films. Under 3 wt% PCDs content, the FSG/ADA/PCDs-3 % composite film not only presented significant antioxidant capacity with a radical scavenging rate of 91.71 % for DPPH and approximately 100 % for ABTS, but also exhibited excellent antimicrobial ability against bacteria and fungi. Results of a preservation experiment showed that the prepared FSG/ADA/PCDs-3 % film preserved the physiological qualities of strawberries post-harvest and extended their shelf-life to 7 days at room temperature. Overall, the fabricated FSG/ADA/PCDs composite films are promising for use in eco-friendly active food packaging.

Characterization and modeling of diffusion kinetics of rosemary oleoresin extract from gellan gum-based film

Fresh food products are highly prone to oxidation and microbial attack, rendering them unsuitable for consumption. Thus, active food packaging was developed to protect and prolong food shelf-life. Zein/gellan gum (GG) based active film is developed by incorporating rosemary oleoresin extract (ROE) (0-20%). The films were characterized by their barrier and antioxidant properties. The release behavior of ROE in fatty and hydrophilic food stimulants was investigated via mathematical modeling. The active films incorporated with 20% ROE have significantly higher oxygen barrier and oxygen transfer is reduced by 20% compared to the control. A tortuous path is created with ROE, which impedes oxygen movement across the film. ROE addition improved water resistance performance by reducing the active film swelling ratio by 31%. This improvement is attributed to the hydrophobic nature of ROE. FTIR shows that the interaction between ROE and the active film is primarily hydrogen bonding and electrostatic interactions. Active film exhibits excellent antioxidant activity, with high TPC, DPPH scavenging activity, and FRAP. Mathematical modeling revealed a higher diffusivity (D) of ROE in fatty food stimulants at 24 °C, attributed to high polarity and solubility in fatty food stimulants. Overall, this active film has an excellent antioxidant effect and could potentially be used as food packaging for high-fat food products to prevent oxidation.

Graphical abstract

Evaluation of a Fish Gelatin-Based Edible Film Incorporated with Ficus carica L. Leaf Extract as Active Packaging

The significant concerns associated with the widespread use of petroleum-based plastic materials have prompted substantial research on and development of active food packaging materials. Even though fish gelatin-based films are appealing as active food packaging materials, they present practical production challenges. Therefore, this study aimed to develop an edible film using Ficus carica L. leaf extract (FLE), as it is affordable, accessible, and has superoxide anion radical scavenging action. This edible film was produced by adding FLE to mackerel skin gelatin at varied concentrations (2.5-10% w/w). The results showed that adding FLE to gelatin films significantly affected the tensile strength (TS), elongation at break (EAB), transmittance and transparency, solubility, water vapor permeability (WVP), antioxidant activity, and antibacterial activity. Among all the samples, the most promising result was obtained for the edible film with FLE 10%, resulting in TS, EAB, solubility, WVP, antioxidant activity, and antibacterial activity against S. aureus and E. coli results of 2.74 MPa, 372.82%, 36.20%, 3.96 × 10-11 g/msPa, 45.49%, 27.27 mm, and 25.10 mm, respectively. The study's overall findings showed that fish gelatin-based films incorporated with FLE are promising eco-friendly, biodegradable, and sustainable active packaging materials.

Preparation of chitosan/Enoki mushroom foot polysaccharide composite cling film and its application in blueberry preservation

In this study, the composite cling film was prepared by solution casting method using chitosan and golden mushroom foot polysaccharide as substrates, and the structure and physicochemical indexes of the composite cling film were characterized by Fourier infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results showed that compared with single chitosan film, the composite cling film has better mechanical properties and antioxidant properties, and the barrier of UV light and water vapor is also stronger. Due to its high nutritional value, blueberry has a short shelf life due to its thin skin and poor storage resistance. Therefore, in this study, blueberry was used as the object of freshness preservation, and the single chitosan film group and the uncovered group were used as controls, and the weight loss, total bacterial colony, decay rate, respiration intensity, malondialdehyde content, hardness, soluble solids, titratable acid, anthocyanin content, and VC content of blueberry were used as freshness preservation indexes for experiments. The comprehensive results showed that the freshness preservation effect of the composite film group was significantly higher than that of the control group, with better antibacterial properties, antioxidant properties, etc., which could effectively delay fruit decay and deterioration, thus prolonging the shelf life, and thus the chitosan/Enoki mushroom foot polysaccharide composite preservation film has a high potential as a new freshness preservation material for blueberry.

Development and Characterization of Antioxidant and Antibacterial Films Based on Potato Starch Incorporating Viola odorata Extract to Improve the Oxidative and Microbiological Quality of Chicken Fillets during Refrigerated Storage

In this research, the antioxidant and antibacterial activities of active films based on potato starch containing Viola odorata extract (VOE) were investigated both in vitro and in chicken fillets. The VOE was added to the starch film formulation at 0, 1, 2, and 3% (w/v). The results showed that by increasing the extract level, the total phenol content and antioxidant and antibacterial activity of the films against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium improved remarkably. The results of the meat tests indicated the significant antioxidant and antimicrobial activity of active films containing different levels of VOE in chicken fillets, and a direct relationship was observed between the concentration of the extract and the functional activity of the films, so with the increase in the concentration of the extract in the films, the rate of lipid oxidation and growth of microorganisms in the chicken fillets decreased significantly during the storage period, and less volatile nitrogen bases, metmyoglobin, and oxidation products were produced in the fillets. In general, the results of this research demonstrated that an active film based on potato starch containing VOE (especially 2 and 3% levels) has the ability to extend the oxidative and microbiological shelf life of chicken fillets during cold storage for at least eight days.

A comparison of the impacts of different polysaccharides on the sono-physico-chemical consequences of ultrasonic-assisted modifications

This study aimed to examine the sono-physico-chemical effects of ultrasound (UND) and its impact on the conjugate rates of morin (MOI) following the addition of polysaccharides in various conditions. In comparison to the control group, the incorporation of quaternary ammonium chitosan decreased the rate of MOI conjugation by 17.38%, but the addition of locust bean gum enhanced the grafting rate by 29.89%. Notably, the highest degree of myofibrillar protein (MRN) unfolding (fluorescence intensity: 114435.50), the most stable state (-44.98 mV), and the greatest specific surface area (393.06 cm²/cm³) were observed in the UMP/LBG group. The outcomes of atomic force microscopy and scanning electron microscopy revealed that the inclusion of locust bean gum led to a different microscopic morphology than the other two polysaccharides, which may be the primary cause of the strongest sono-physico-chemical effects of the system. This work demonstrated that acoustic settings can be tuned based on the characteristics of polysaccharides to maximize the advantages of sono-physico-chemical impacts in UND-assisted MOI processing.

Acylated pectin/gelatin-based films incorporated with alkylated starch crystals: Characterization, antioxidant and antibacterial activities, and coating preservation effects on golden pomfret

Pectin and starch crystals were modified by ethyl gallate and octadecyl-trimethoxysilane, respectively, followed by using acylated pectin (AP) and alkylated starch crystals (ASCs) as bioactive reagents and hydrophobic enhancers to improve the physiochemical properties of gelatin-based films and evaluate their coating preservation effects on golden pomfret. The properties of AP and ASC were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), proton-nuclear magnetic resonance (¹H NMR) and X-ray diffraction (XRD). The ethyl-gallate-modified pectin/gelatin (AP/G) containing 3 % ASC (AP/G/ASC-3 %) was shown to have the maximum tensile strength and Young's modulus of all the tested composite films. The AP/G containing 10 % ASC exhibited a water contact angle higher than 94°, coupled with a significant improvement in UV-shielding efficiency. FTIR and SEM analysis of the AP/G/ASC-3 % film indicated that the molecular interactions in the composite film components were noncovalent linkages, including hydrogen bonds, hydrophobic interactions, and electrostatic interactions, contributing to homogeneous and smooth microstructures. Additionally, the solutions of AP/G and AP/G/ASC composite films presented obvious antioxidant and antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the AP/G and AP/G/ASC active coatings could effectively inhibit lipid oxidation and improve the textural acceptability of golden pomfret (Trachinotus blochii) fillets during 4 °C storage.

Composite films based on carboxy methyl cellulose and sodium alginate incorporated Thymus vulgaris purified leaves extract for food application: Assessment, antimicrobial and antioxidant properties

The current study was conducted to develop biodegradable films with matrix composed from carboxymethyl cellulose (CMC), sodium alginate (SA) and different concentrations from Thymus vulgaris purified leaves extract (TVE). The color properties, physical properties, shape of surface, manners of crystallinity, mechanical properties and thermal properties of produced films were investigated. The continuous addition of TVE up to 1.6 % inside films matrix imparted the yellow color of extract that increased opacity to 2.98 and reduced moisture, swelling, solubility and water vapor permeability (WVP) of films up to 10.31 %, 30.17 %, 20.18 % and (1.12× 10^-10 g.m^-1 s^-1 pa^-1), respectively. Furthermore, the surface micrographs showed smoother surface after using small concentrations of TVE and turned to irregular with rough surface at higher concentrations. The FT-IR analysis indicated typically bands that demonstrated physical interaction between TVE extract and CMC/SA matrix. The fabricated films showed suitable thermal stability with decreasing trend by incorporation of TVE inside CMC/SA films. Furthermore, the developed CMC/SA/TVE2 showed significant effects on preserving the levels of moisture content, titrable acidity, force to puncture and sensory properties of cheddar cheese during cold storage days compared with commercial packaging materials.

Development and characterization of tapioca starch/pectin composite films incorporated with broccoli leaf polyphenols and the improvement of quality during the chilled mutton storage

This study aimed at the composition of active packaging film from tapioca starch/pectin (TSP) incorporated with broccoli leaf polyphenols (BLP) was prepared and applied to improve the qualities of the chilled mutton during storage. The results indicated the addition of BLP significantly improved the thickness, density, barrier ability, mechanical properties, water solubility and antioxidant activity of the composite films while inducing decreases in the brightness (p < 0.05), enhancing inter-molecular interactions of TSP + BLP composite films. The WVP, oxygen permeability and elongation at break of the composite film reached the minimum when BLP concentration was 3 % while exhibiting the highest tensile strength and the best performance. This composite film delayed microbial growth and minimized oxidative rancidity during chilled mutton storage, causing the improvement of its quality and extending its shelf life to 12 days. Therefore, TSP + BLP composite films possessed the promise to be applied as bioactive materials in food packaging sectors.

Development and characterization of pectin and chitosan films incorporated with a new cross-linking agent

BACKGROUND

In this study, a new crosslinking agent (CA) containing whey protein, papin, glycerin, and epigallocatechin gallate (EGCG), was prepared. The effects of CA content (0, 10, 20, 30, and 40%, v/v) on food packaging properties, crystallinity, microstructure, and antioxidant properties of pectin-CA and chitosan-CA composite films were analyzed. The results of this research offer a theoretical basis for engineering improved films for food packing.

RESULTS

Pectin-CA (30%) and chitosan-CA (40%) composite films showed the best light transmission, water retention, breathability, plasticity, and antioxidant activity. Scanning electron microscopy revealed that these composite films exhibited a uniform and homogeneous structure without obvious pores. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the amino acids and EGCG in CA were bonded to the film substrate (pectin/chitosan) via electrostatic interactions, hydrogen bonding, and covalent bonding, which led to an improvement in the film's properties.

CONCLUSION

The CA has broad application prospects in food packaging as a cross-linking agent and antioxidant. © 2022 Society of Chemical Industry.

Incorporating Portulaca oleracea extract endows the chitosan-starch film with antioxidant capacity for chilled meat preservation

This study aimed to investigate the application potential of Portulaca oleracea extract (POE) in active packaging for the preservation of chilled meat. First, the antioxidant capacity and active ingredients of POE were systematically studied. The results demonstrated that POE has excellent antioxidant capacity and contains abundant antioxidant compounds. Subsequently, antioxidant-active packaging films based on chitosan and starch containing different concentrations of POE (CS/POE films) were successfully developed. The main physicochemical and mechanical properties of the CS/POE films were characterized and evaluated. The CS/POE films exhibited remarkable antioxidant activity and can significantly reduce lipid oxidation in meat. Compared with polyethylene film, the CS/POE films-treated meats had better preservation effects and longer shelf-life. These findings suggested that CS/POE film has the potential to become a good alternative to conventional plastics in food packaging. In conclusion, Portulaca oleracea extract is an excellent natural antioxidant with great potential in active packaging for chilled meat preservation.

Ultrasound assisted treatment improves the preservation performance of chitosan-grafted-chlorogenic acid on refrigerated sea bass (Lateolabrax japonicus) fillets

BACKGROUND

Ultrasound can increase the mass transfer between preservatives and food, and enhances the effect of preservatives on food. Chitosan-grafted-chlorogenic acid (CS-g-CA) is a new synthetic compound with good antiseptic properties. Therefore, the present study evaluated the preservation performance of ultrasound-assisted CS-g-CA (GUA) coatings on refrigerated sea bass fillets in terms of changes in microorganisms, lipids, proteins, tissue structures, and moisture.

RESULTS

The results showed that GUA treatment effectively inhibited the growth of microorganisms in sea bass fillets. Meanwhile, the changes in total volatile basal nitrogen, thiobarbituric acid reactive substances, and pH values were all slowed down under GUA treatment, indicating that protein degradation and lipid oxidation in sea bass were inhibited. Low-field nuclear magnetic resonance and magnetic resonance imaging results indicated that the GUA retarded the conversion of mobile water to free water. In addition, GUA treatment maintained the flavor quality of fish fillets, and also inhibited the reduction of inosine monophosphate and the production of bitter substances (inosine and hypoxanthine), suppressed muscle tissue degeneration, and maintained better sensory scores.

CONCLUSION

Overall, GUA treatment inhibited microbial growth, protein degradation, lipid oxidation, moisture migration, decomposition of umami substances, and deterioration of sensory quality in sea bass fillets. Finally, the shelf-life of sea bass fillets with GUA treatment was extended by an additional 9 days. The results showed that ultrasonic assistance further enhanced the effect of preservatives on aquatic products. © 2022 Society of Chemical Industry.

Inhibitory effects of ultrasonic and rosmarinic acid on lipid oxidation and lipoxygenase in large yellow croaker during cold storage

Lipid oxidation will lead to the deterioration of flavor, color and texture of aquatic products with high fatty acid content. The mechanism of ultrasound (US) combined with rosmarinic acid (RA) on lipid oxidation and endogenous enzyme activities of large yellow croaker during cold-storage (4 ℃) was investigated. The result showed that the US and RA have synergistic effects in delaying lipid oxidation and inhibiting endogenous lipase and lipoxygenase (LOX) activities related to oxidation. The inhibition of LOX activity by RA was dose-dependent, and US showed a negative effect on the inhibition of enzyme activity in the presence of low concentration RA. Moreover, RA changes the enzyme structure through static fluorescence quenching and interaction with enzyme molecules. Hydrogen bonding and hydrophobic interaction are the main interaction forces between RA and LOX. This study could provide basic mechanism of US treatment cooperating with polyphenols to inhibit lipid oxidation during food preservation.

Developing Technology for the Production of Innovative Coatings with Antioxidant Properties for Packaging Fish Products

In this study, we investigated the effects of furcellaran−gelatine (FUR/GEL) coatings incorporated with herb extracts on the quality retention of carp fish during refrigeration. Nutmeg, rosemary, thyme, milfoil, marjoram, parsley, turmeric, basil and ginger were subjected to water and ethanol extraction methods (10% concentration of herbs). The water extractions of the rosemary and thyme (5%) were used for the further development of coatings due to their high 2,2-Diphenyl-1-picrylhydrazyl (DPPH: 85.49 and 83.28%) and Ferric Reducing Antioxidant Power Assay values (FRAP: 0.46 and 0.56 mM/L) (p < 0.05), respectively. A new, ready-to-cook product with the coatings (carp fillets) was evaluated regarding quality in terms of colour parameters, texture profile, water activity, Thiobarbituric Acid Reactive Substances (TBARSs) and sensory analyses during 12 days of storage at 4 °C. The results show that the colour of the carp fillets treated with the rosemary and thyme extracts became slightly darker and had a propensity towards redness and yellowness. In contrast to the control group, the carp fillets stored in the coatings with the rosemary extract effectively slowed the lipid oxidation processes. Therefore, the innovative coatings produced from carp processing waste may have high potential as components in convenience food products and could extend the shelf-life of carp fillets during refrigerated storage. However, further research is needed to assess the microbiological stability of the obtained food products.

Inhibitory effects of chitosan grafted chlorogenic acid on antioxidase activity, and lipid and protein oxidation of sea bass (Lateolabrax japonicus) fillets stored at 4 °C

BACKGROUND

Sea bass (Lateolabrax japonicus), a marine fish, is prone to spoilage due to its high nutritional value. Preservatives are commonly used for storage for the production of fish fillets. In this work, chitosan (CS) was grafted onto chlorogenic acid (CA) to obtain a new preservative, chitosan grafted chlorogenic acid (CS-g-CA), which could enhance the biochemical properties of chitosan and obtain better antibacterial and antibacterial properties. This study therefore investigated the inhibitory effects of CS-g-CA on antioxidant enzyme activity, and lipid and protein oxidation of sea bass fillets stored at 4 °C.

RESULTS

Compared with the control group on day 9, the activity of 63% catalase (CAT), 78% superoxide diamidase (SOD), 73% glutathione peroxide enzyme (GSH-Px) and 60% DPPH scavenging activity was retained by CS-g-CA treatment. Changes in thiobarbituric acid (TBA) and conjugated diene (CD) values were delayed by CS-g-CA treatment. The use of CS-g-CA retards protein oxidation by inhibiting the formation of free amino acid and carbonyl groups, and maintaining a higher sulfhydryl content. Regarding myofibril degradation, CS-g-CA could maintain protein secondary structure by increasing the ratio of α-helices.

CONCLUSIONS

Chitosan-grafted chlorogenic acid could protect the activity of antioxidant enzymes and inhibit lipid oxidation by slowing down the production of lipid oxidation products. It also delayed protein oxidation by inhibiting oxidation product generation and stabilizing protein structure. It could therefore be used as a promising preservative for seafood. © 2022 Society of Chemical Industry.

Antioxidant and antimicrobial chitosan films enriched with aqueous sage and rosemary extracts as food coating materials: Characterization of the films and detection of rosmarinic acid release

Chitosan films containing aqueous extracts of sage and rosemary were prepared as a potential food coating material with antioxidant and antibacterial properties. The effect of adding extracts at different concentrations on the mechanical, physical, and optical properties of the films was investigated. The addition of the extracts significantly increased Young's modulus values of the films compared to the chitosan film, and a significant decrease was observed in the swelling percentage and water vapor permeability of the films. Since all the prepared films were ionically cross-linked, the increase in water solubility of the films with the addition of the extract was at a low level. The release of rosmarinic acid, which is found in significant amounts in both plants, from the films was monitored by the capillary electrophoresis. The antioxidant properties imparted to the films by the addition of plant extracts were determined by DPPH and FRAP methods. The addition of plant extracts increased the antimicrobial property of chitosan films against Staphylococcus aureus and Escherichia coli. Films containing sage and rosemary extracts showed potential for use as food coating materials.

A Bioactive Chitosan-Based Film Enriched with Benzyl Isothiocyanate/α-Cyclodextrin Inclusion Complex and Its Application for Beef Preservation

A bioactive packaging material based on chitosan (CS) incorporated with benzyl isothiocyanate (BITC) and α−cyclodextrin (α−CD) was fabricated to evaluate its preservative effects on fresh beef stored at 4 °C for 12 d according to the quality analysis. The Fourier-transform infrared (FTIR) spectrum revealed that the major structural moiety of BITC was embedded in the cavity of α−CD, except for the thiocyanate group. FTIR and X-ray diffraction analysis further verified that intermolecular interactions were formed between the BITC−α−CD and CS film matrix. The addition of BITC−α−CD decreased the UV light transmittance of pure CS film to lower than 63% but still had enough transparency for observing packaged items. The CS−based composite film displayed a sustainable antibacterial capacity and an enhanced antioxidant activity. Moreover, the total viable counts, total volatile base nitrogen, pH, thiobarbituric acid–reactive substances, and sensory evaluation of the raw beef treated with the CS−based composite film were 6.31 log colony-forming unit (CFU)/g, 19.60 mg/100 g, 6.84, 0.26 mg/kg, and 6.5 at 12 days, respectively, indicating the favorable protective efficacy on beef. These results suggested that the fabricated CS−based composite film has the application potential to be developed as a bioactive food packaging material, especially for beef preservation.

Emerging Approach for Fish Freshness Evaluation: Principle, Application and Challenges

Affected by micro-organisms and endogenous enzymes, fish are highly perishable during storage, processing and transportation. Efficient evaluation of fish freshness to ensure consumer safety and reduce raw material losses has received an increasing amount of attention. Several of the conventional freshness assessment techniques have plenty of shortcomings, such as being destructive, time-consuming and laborious. Recently, various sensors and spectroscopic techniques have shown great potential due to rapid analysis, low sample preparation and cost-effectiveness, and some methods are especially non-destructive and suitable for online or large-scale operations. Non-destructive techniques typically respond to characteristic substances produced by fish during spoilage without destroying the sample. In this review, we summarize, in detail, the principles and applications of emerging approaches for assessing fish freshness including visual indicators derived from intelligent packaging, active sensors, nuclear magnetic resonance (NMR) and optical spectroscopic techniques. Recent developments in emerging technologies have demonstrated their advantages in detecting fish freshness, but some challenges remain in popularization, optimizing sensor selectivity and sensitivity, and the development of algorithms and chemometrics in spectroscopic techniques.