Packaging of beef fillet with active chitosan film incorporated with ɛ-polylysine: An assessment of quality indices and shelf life

Recent advances in spoilage mechanisms and preservation technologies in beef quality: A review

Beef is a popular meat product that can spoil and lose quality during postharvest handling and storage. This review examines different preservation methods for beef, from conventional techniques like low-temperature preservation, irradiation, vacuum packing, and chemical preservatives, to novel approaches like bacteriocin, essential oil, and non-thermal technologies. It also discusses how these methods work and affect beef quality. The review shows that beef spoilage is mainly due to enzymatic and microbial activities that impact beef freshness, texture, and quality. Although traditional preservation methods can extend beef shelf life, they have some drawbacks and limitations. Therefore, innovative preservation methods have been created and tested to improve beef quality and safety. These methods have promising results and potential applications in the beef industry. However, more research is needed to overcome the challenges and barriers for their commercialization. This review gives a comprehensive and critical overview of the current and emerging preservation methods for beef and their implications for the beef supply chain.

Biopolymer-based packaging films/edible coatings functionalized with ε-polylysine: New options for food preservation

In light of the commendable advantages inherent in natural polymers such as biocompatibility, biodegradability, and cost-effectiveness, researchers are actively engaged in the development of biopolymer-based biodegradable food packaging films (BFPF). However, a notable limitation is that most biopolymers lack intrinsic antimicrobial activity, thereby restricting their efficacy in food preservation. To address this challenge, various active substances with antibacterial properties have been explored as additives to BFPF. Among these, ε-polylysine has garnered significant attention in BFPF applications owing to its outstanding antibacterial properties. This study provides a brief overview of the synthesis method and chemical properties of ε-polylysine, and comprehensively examines its impact as an additive on the properties of BFPF derived from diverse biopolymers, including polysaccharides, proteins, aliphatic polyesters, etc. Furthermore, the practical applications of various BFPF functionalized with ε-polylysine in different food preservation scenarios are summarized. The findings underscore that ε-polylysine, functioning as an antibacterial agent, not only directly enhances the antimicrobial activity of BFPF but also serves as a cross-linking agent, interacting with biopolymer molecules to influence the physical and mechanical properties of BFPF, thereby enhancing their efficacy in food preservation.

Characterization and Antioxidant and Antibacterial Activities of Carboxymethylated Tamarind Seed Polysaccharide Composite Films Incorporated with ε-Polylysine and Their Application in Fresh-Cut Green Bell Pepper Preservation

Traditional petroleum-based food-packaging materials have poor permeability, limited active packaging properties, and difficulty in biodegradation, limiting their application. We developed a carboxymethylated tamarind seed polysaccharide composite film incorporated with ε-polylysine (CTPε) for better application in fresh-cut agricultural products. The CTPε films exhibit excellent water vapor barrier properties, but the mechanical properties are slightly reduced. Fourier transform infrared spectroscopy and X-ray diffraction spectra indicate the formation of hydrogen bonds between ε-PL and CTP, leading to their internal reorganization and dense network structure. With the increase of ε-PL concentration, composite films showed notable inhibition of postharvest pathogenic fungi and bacteria, a significant enhancement of 2,2'- azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity, and gradual improvement of wettability performance. Cytotoxicity experiments confirmed the favorable biocompatibility when ε-PL was added at 0.3% (CTPε2). In fresh-cut bell pepper preservation experiments, the CTPε2 coating effectively delayed weight loss and malondialdehyde increase preserved the hardness, color, and nutrients of fresh-cut peppers and prolonged the shelf life of the fresh-cut peppers, as compared with the control group. Therefore, CTPε composite films are expected to be a valuable packaging material for extending the shelf life of freshly cut agricultural products.

Pullulan nanofibrous films incorporated with W/O emulsions via microfluidic solution blow spinning technology

In this work, pullulan (PUL) nanofibrous films incorporated with water-in-oil emulsions (PE) were prepared by microfluidic blowing spinning (MBS). The microstructures of nanofibers were characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR), and X-ray diffraction (XRD). With the addition of W/O emulsions, the thermal stability, mechanical, and water barrier properties of PUL nanofibers were improved. Increases in emulsion content significantly affected the antioxidant and antimicrobial properties of nanofibrous films. ABTS and DPPH free radical scavenging rates increased from 10.26 % and 8.57 % to 60.66 % and 57.54 %, respectively. The inhibition zone of PE nanofibers against E. coli and S. aureus increased from 11.00 to 20.00 and from 15.67 to 21.17 mm, respectively. In addition, we investigated the freshness effectiveness of PE nanofibrous films on fresh-cut apples. PE nanofibrous films significantly maintained the firmness, and reduced the weight loss and browning index of the fresh-cut apple, throughout the 4 days of storage. Thus, the PE nanofibrous films exhibited good potential to prolong the shelf life of fresh-cut fruit and promote the development of active food packaging.

Advanced technologies in biodegradable packaging using intelligent sensing to fight food waste

The limitation of conventional packaging in demonstrating accurate and real-time food expiration dates leads to food waste and foodborne diseases. Real-time food quality monitoring via intelligent packaging could be an effective solution to reduce food waste and foodborne illnesses. This review focuses on recent technological advances incorporated into food packaging for monitoring food spoilage, with a major focus on paper-based sensors and their combination with smartphone. This review paper offers a comprehensive exploration of advanced macromolecular technologies in biodegradable packaging, a general overview of paper-based probes and their incorporation into food packaging coupled with intelligent sensing mechanisms for monitoring food freshness. Given the escalating global concerns surrounding food waste, our manuscript serves as a pivotal resource, consolidating current research findings and highlighting the transformative potential of these innovative packaging solutions. We also highlight the current intelligent paper-based food freshness sensors and their various advantages and limitations. Examples of implementation of paper-based sensors/probes for food storage and their accuracy are presented. Finally, we examined how intelligent packaging can be an alternative to reduce food waste. Several technologies discussed here have good potential to be used in food packaging for real-time food monitoring, especially when combined with smartphone diagnosis.

Carbon dots embedded bacterial cellulose membrane as active packaging: Toxicity, in vitro release and application in minced beef packaging

Antimicrobial bacterial cellulose (BC) membranes incorporated with carbon dots (CDs) were developed to improve the shelf life and ensure the safety of minced beef during 9 days of storage at 4 °C. An ex-situ method was used to develop BC-CDs with different CDs loading capacities (16.50, 22.50, and 38.50 mg/cm3). Only BC-CDs38.50 membrane exhibited toxicity in human embryonic kidney cells, and BC-CDs membranes had the slowest release rate of CDs in 95% ethanol. Significant differences were noted in the chemical and sensory attributes of samples packaged with BC-CDs16.50 and BC-CDs22.50, compared to the control. The microbial counts in samples with BC-CDs were significantly lower than those in samples with pristine BC membranes or the control. Notably, the BC-CDs22.50 membrane exhibited a substantial reduction (4.7 log10 CFU/g) in Escherichia coli counts by the end of storage. These findings highlight the potential of BC-CDs membranes as effective antimicrobial materials in meat packaging.

Electrospun Konjac Glucomannan/Polyvinyl Alcohol Long Polymeric Filaments Incorporated with Tea Polyphenols for Food Preservations

In this study, nanofiber films were prepared by electrospinning technology with polyvinyl alcohol (PVA) and konjac glucomannan (KGM) as raw materials. Tea polyphenols (TPs) were incorporated in the above matrix, which increased physicochemical (thermal and mechanical characteristics) and antibacterial properties of the nanofiber films. The release behavior of phenolic compounds from PVA/KGM-TPs nanofiber films was determined in different food simulants; antioxidant and antibacterial activity of the films were also evaluated. The results showed that the addition of KGM increased the physical and chemical properties of the films. The tensile strength (TS) and elongation at break (EB) increased from 5.40 ± 0.33 to 10.62 ± 0.34 and from 7.24 ± 0.32 to 18.10 ± 0.91, respectively. PVA/KGM-TPs nanofiber films performed controlled release of TPs, with final release of 49.17% in 3% acetic acid, 43.6% in 10% ethanol, and 59.42% in 95% ethanol. The nanofiber films showed good antioxidation properties, with the free radical scavenging rate increasing from 1.33% to 25.61%, and good antibacterial properties with inhibition zones against E. coli and S. aureus of 24.33 ± 0.47 mm and 34.33 ± 0.94 mm, respectively. In addition, the as-prepared films showed significant preservation performance for raw bananas at 25 °C.

An overview of the potential application of chitosan in meat and meat products

Chitosan is considered the second most ubiquitous polysaccharide next to cellulose. It has gained prominence in various industries including biomedicine, textile, pharmaceutical, cosmetic, and notably, the food industry over the last few decades. The polymer's continual attention within the food industry can be attributed to the increasing popularity of greener means of packaging and demand for foods incorporated with natural alternatives instead of synthetic additives. Its antioxidant, antimicrobial, and film-forming abilities reinforced by the polymer's biocompatible, biodegradable, and nontoxic nature have fostered its usage in food packaging and preservation. Microbial activity and lipid oxidation significantly influence the shelf-life of meat, resulting in unfavorable changes in nutritional and sensory properties during storage. In this review, the scientific studies published in recent years regarding potential applications of chitosan in meat products; and their effects on shelf-life extension and sensory properties are discussed. The utilization of chitosan in the form of films, coatings, and additives in meat products has supported the extension of shelf-life while inducing a positive impact on their organoleptic properties. The nature of chitosan and its compatibility with various materials make it an ideal biopolymer to be used in novel arenas of food technology.

Comparison of the Properties of Pullulan-Based Active Edible Coatings Implemented for Improving Sliced Cheese Shelf Life

The development of active edible coatings with improved mechanical and barrier properties is a huge challenge. In this study, active edible coatings for sliced cheese have been developed using pullulan (Pull) in combination with two different biopolymers, chitosan (CS) and gelatine (Gel), and a combination of hydrolats as a source of active compounds with antimicrobial effects. In comparison to the monolayer coating, the bilayer coating system demonstrates improved barrier and mechanical properties. A preliminary assessment of the antimicrobial effect of lemongrass and curry plant hydrolats has revealed that both hydrolats exhibited antimicrobial activity against the targeted bacterium Staphylococcus aureus, albeit at different levels. The obtained results suggest that a mixture of 1.56% lemongrass and 12.5% curry plant hydrolats yielded a lower fractional inhibitory concentration (FIC) value. Bilayer coating systems (Pull/CS and Pull/Gel) with an incorporated mixture of hydrolats have demonstrated effectiveness in both cases: artificial contamination before application of the coating system and after application of the coating system. In both contamination scenarios, the coating systems consistently effectively limited bacterial proliferation, indicating the antimicrobial effect of the hydrolat mixture in the coating layers. In the case of artificial contamination before applying the coating system, both coatings demonstrated antimicrobial effectiveness, but the formulation with chitosan had a biocide effect, while the other, with gelatine, had only a bacteriostatic effect in a long-term setting. In the second case, both Pull/CS and Pull/Gel coatings demonstrated effectiveness in inhibiting bacterial growth regardless of the moment of contamination of the sample; the Pull/CS coating showed slightly better antimicrobial activity, achieving complete elimination of bacteria earlier compared with the Pull/Gel coating system.

Synthesis and characterization of polysaccharide- and protein-based edible films and application as packaging materials for fresh fish fillets

The rising packaging industry together with global demand for sustainable production has increased the interest in developing biodegradable packaging materials. The aim of the study was to develop edible films based on pectin, gelatin, and hydroxypropyl methylcellulose and evaluate their applicability as biodegradable packaging materials for gilthead seabream fillets. Mechanical properties, water barriers, wettability of the films through contact angle measurement, optical, and UV-Vis barrier properties were evaluated for food packaging applications. The effective blend of polysaccharide and protein film-forming solutions was confirmed by the produced films with excellent optical properties, acceptable mechanical properties and adequate barriers to water vapor. The contact angle for pectin based and gelatin based films were higher than 90° indicating the hydrophobic films, while HPMC based films had contact angle lower than 90°. The produced films were tested as alternative and environmentally friendly packaging materials for gilthead seabream fillets during refrigerated storage. All tested packaging conditions resulted in similar shelf-life in packed gilthead seabream fillets (i.e. 7-8 days at 2 °C). The results showed that the developed films may reduce the use of conventional petroleum-based food packaging materials without affecting the shelf-life of fish.

Effect of coating with combined chitosan and gallic acid on shelf-life stability of Jeju black cattle beef

OBJECTIVE

Beef of Jeju black cattle (JBC) is considered as a healthy meat type due to its significantly higher unsaturated fatty acids (UFA). Lipid (e.g., UFA) is highly susceptible to oxidizing agents, which results in the quality deterioration and economic value loss of meat products. Therefore, development and application of novel preservative techniques is necessary to improve the shelf-life stability of high-UFA beef. The objective of this study was to assess the applicability of chitosan-based coatings in preservation of JBC beef.

METHODS

Different coating solutions: 2% chitosan alone, and 2% chitosan containing 0.1% or 0.3% gallic acid were prepared to investigate their applicability in preservation of fresh beef during storage. Jeju black cattle beef (2-cm thick steaks) were non-coated (control) or coated with the above coating solutions, placed on trays, over-wrapped with plastic film and stored at 4°C. The microbiological indices, color, total volatile basic nitrogen (TVBN) and lipid oxidation of the beef were investigated after 1, 10, and 21 days of storage.

RESULTS

Coating with 2% chitosan alone reduced the spoilage bacteria count, TVBN and thiobarbituric acid reactive substances levels in the beef compared with control during storage (p<0.05). Noticeably, coating with 2% chitosan containing 0.1% or 0.3% gallic acid was more effective on retardation of spoilage bacteria growth, lipid oxidation and discoloration in the beef compared to the chitosan coating alone over the storage period (21 days) (p<0.05).

CONCLUSION

Taken together, the combined chitosan and gallic acid coating could be used as a bio-preservative technique in the meat industry.

The effects of double gelatin containing chitosan nanoparticles-calcium alginate coatings on the stability of chicken breast meat

The effects of gelatin coatings (2% and 4%) containing chitosan nanoparticles (ChNPs; 1% and 2%), in combination with calcium-alginate coatings (CA; 2%), on quality attributes and shelf life of chicken breast meat were evaluated at 4°C for 12 days. The results indicated that double-active gelatin-calcium alginate coatings had significant (p < .05) effects on moisture and protein content. Incorporation of ChNPs into double gelatin-CA coatings led to significant reduction (p < .05) in TBARS, pH, and TVB-N values at the end of storage. The counts of total viable count (TVC), coliforms, yeasts, and molds were significantly (p < .05) lower in all coated samples, particularly in treated samples by 4% gelatin containing 2% ChNPs + 2% CA coatings (6.85, 6.78, and 5.91 log CFU/g, respectively, compared with 8.35, 8.76, and 7.71 log CFU/g in control) at the end of keeping time. The results of sensory attributes showed that the coated samples had higher overall acceptability scores compared with the untreated samples. A synergistic relationship between the concentrations of gelatin and ChNPs was observed in maintaining the quality characteristics of meat samples during storage. Therefore, this study aims to evaluate the performance of double gelatin coating containing ChNPs in combination with CA coating in the storage quality improvement of chicken breast meat stored for 12 days at 4 °C to develop novel and practical coatings for meat and meat products.

Starch-gelatin blend films: A promising approach for high-performance degradable food packaging

Packaging plays a vital role in safeguarding food from environmental factors and contamination. However, the overuse and improper disposal of non-biodegradable plastic packaging materials have led to environmental concerns and health risks. To address these challenges, the development of degradable food packaging films is crucial. Biodegradable polymers, including natural biopolymers like starch (ST) and gelatin (GE), have emerged as promising alternatives to traditional plastics. This review focuses on the utilization of ST-GE blends as key components in composite films for food packaging applications. We discuss the limitations of pure ST-GE films and explore methods to enhance their properties through the addition of plasticizers, cross-linkers, and nanoparticles. The blending of ST-GE, facilitated by their good miscibility and cross-linking potential, is highlighted as a means to improve film performance. The review also examines the impact of various additives on the properties of ST-GE blend films and summarizes their application in food preservation. By providing a comprehensive overview of ST-GE hybrid systems, this study aims to contribute to the advancement of sustainable and effective food packaging solutions.

The Gelatin-Coated Nanostructured Lipid Carrier (NLC) Containing Salvia officinalis Extract: Optimization by Combined D-Optimal Design and Its Application to Improve the Quality Parameters of Beef Burger

The current study aims to synthesize the gelatin-coated nanostructured lipid carrier (NLC) to encapsulate sage extract and use this nanoparticle to increase the quality parameters of beef burger samples. NLCs were prepared by formulation of gelatin (as surfactant and coating biopolymer), tallow oil (as solid lipid), rosemary essential oil (as liquid lipid), sage extract (as active material or encapsulant), polyglycerol ester and Tween 80 (as low-molecular emulsifier) through the high-shear homogenization-sonication method. The effects of gelatin concentrations and the solid/liquid ratio on the particle size, polydispersity index (PDI), and encapsulation efficiency (EE%) of sage extract-loaded NLCs were quantitatively investigated and optimized using a combined D-optimal design. Design expert software suggested the optimum formulation with a gelatin concentration of 0.1 g/g suspension and solid/liquid lipid ratio of 60/40 with a particle size of 100.4 nm, PDI of 0.36, and EE% 80%. The morphology, interactions, thermal properties, and crystallinity of obtained NLC formulations were investigated by TEM, FTIR, DSC, and XRD techniques. The optimum sage extract-loaded/gelatin-coated NLC showed significantly higher antioxidant activity than free extract after 30 days of storage. It also indicated a higher inhibitory effect against E. coli and P. aeruginosa than free form in MIC and MBC tests. The optimum sage extract-loaded/gelatin-coated NLC, more than free extract, increased the oxidation stability of the treated beef burger samples during 90 days of storage at 4 and -18 °C (verified by thiobarbituric acid and peroxide values tests). Incorporation of the optimum NLC to beef burgers also effectively decreased total counts of mesophilic bacteria, psychotropic bacteria, S. aureus, coliform, E. coli, molds, and yeasts of treated beef burger samples during 0, 3, and 7 days of storage in comparison to the control sample. These results suggested that the obtained sage extract-loaded NLC can be an effective preservative to extend the shelf life of beef burgers.

The Combination of Corona Discharge Plasma and ε-Polylysine for the Inactivation of Serratia liquefaciens

The purpose of the study was to investigate the mechanism of inactivation of Serratia liquefaciens by different treatments, namely corona discharge plasma (CDP), ε-polylysine (ε-PL), and corona discharge plasma combined with ε-polylysine (CDP plus ε-PL). The results showed that the combined treatment of CDP and ε-PL exhibited significant antibacterial effects. The total number of colonies of S. liquefaciens dropped by 0.49 log CFU/mL following 4 min of CDP treatment, 4MIC ε-PL treatment for 6 h alone decreased the amounts of colonies by 2.11 log CFU/mL, and 6 h of treatment with 4MIC ε-PL after the bacterium was treated with CDP could decrease the number of colonies by 6.77 log CFU/mL. Scanning electron microscopy images showed that the combined treatment of CDP and ε-PL caused the most serious damage to the cell morphology. Electrical conductivity, nucleic acid, and PI staining indicated that the combined treatment dramatically enhanced the permeability of the cell membrane. In addition, the combined treatment led to a significant decrease in SOD and POD enzyme activities in S. liquefaciens, which prevented energy metabolism. Finally, the determination of free and intracellular ε-PL concentrations confirmed that the treatment of CDP could cause the bacteria to bind more ε-PL and exert more significant bacterial inhibition. Therefore, CDP and ε-PL had a synergistic effect in the inhibition of S. liquefaciens.

A review of food preservation based on zein: The perspective from application types of coating and film

The application of zein in food preservation was discussed from a unique perspective of application types, including coating and film. For the study of coating, edibility is considered because the coating adheres to the surface of food directly. For the study of film, plasticizers improve their mechanical properties, while barrier performance and antibacterial performance are achieved by nanoparticles; the incorporation of polyphenols is mainly due to their antibacterial and antioxidant properties; other biopolymers realize the complementarity between zein and biopolymers within films. In the future, the interaction between the edible coating and food matrix needs to be concerned. The mechanism of various exogenous additives and zein in the film should be noticed. Importantly, food safety and the possibility of large-scale application should be followed. Additionally, the intelligent response is one of the key development directions of zein-based film in the future.

Novel PVA/carboxylated cellulose antimicrobial hydrogel grafted with curcumin and ε-polylysine for chilled chicken preservation

PVA/CC/CUR/PL composite films containing curcumin (CUR) and ε-polylysine (PL) were prepared by casting and chemical grafting methods to address the threat to food spoilage. Morphological analysis showed that the grafting of CUR and PL resulted in a rough cross-section of the polymer matrix. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the grafting of CUR and PL into the polymer matrix via esterification and amidation reactions, respectively. Thermal weight loss analysis showed that grafting process positively improved the thermal stability. The PVA/CC/CUR/PL films exhibited strong bactericidal activity, reaching 99.0% and 99.8% for Pseudomonas lundensis and Shewanella putrefaciens, respectively. After 8 days of storage, the total number of colonies and the TVB-N content in the PVA/CC/CUR/PL group decreased by 1.51 lg CFU/g and 13.77 mg/100 g, respectively. Therefore, PVA/CC/CUR/PL films are considered as a promising bactericidal material with good mechanical properties, functionality, and other excellent characteristics.

Study on film forming characteristic of ε-polylysine grafted chitosan through TEMPO oxidation system and its preservation effects for pork fillet

The present study synthesized a new type of ε-polylysine (PL) modified chitosan film (TO-CH-PL) through TEMPO (2,2,6,6-Tetramethylpiperidine) oxidation system. Firstly, the physicochemical properties of the TO-CH-PL were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive spectrometer analysis. Results proved that PL was successfully grafted onto chitosan molecules. Based on the water vapor, oxygen permeability, and mechanical analysis, the TO-CH-PL film demonstrated higher physical properties than chitosan and PE films. Secondly, the TO-CH-PL film's preservation effect on pork fillets was evaluated. Due to the significant retardation of growth of the aerobic plate count (APC), total volatile basic nitrogen (TVBN), and thiobarbituric acid reactive substances (TBARS), as well as the changes of pH and color in packaged pork, TO-CH-PL film exhibited better preservation effects for the pork samples. According to the criteria of TVBN values (<15 mg/100 g), compared with CH and PE films, TO-CH-PL film can prolong the shelf life of pork for 2 to 3 days. Therefore, PL-modified chitosan films could be introduced as an alternative method to maintain the quality indices and extend the shelf life of pork during refrigerated storage.

Application of oleaster leaves (Elaeagnus angustifolia L.) essential oil and natural nanoparticle preservatives in frankfurter-type sausages: An assessment of quality attributes and stability during refrigerated storage

The effects of oleaster leave essential oil (OLEOs: 1000 and 2000 ppm) in combination with nisin nanoparticles (200 ppm) and ε-polylysine nanoparticles (2000 ppm) on the physicochemical, microbiological and sensory properties of the emulsion-type sausages without added chemical nitrite/nitrate salts were evaluated during 45 days of storage. Nanoparticle attributes were assessed, including encapsulation efficiency (EE%), zeta potential, nanoparticles size, FTIR analysis, and thermal stability (DSC). Overall, ε-PL nanoparticles (ε-PL-NPs) were thermally more stable and showed higher EE% (91.52%) and zeta potential (37.80%) as compared to nisin nanoparticles (82.85%) and (33.60%), respectively. The use of combined ε-PL-NPs (2000 ppm) + Ni-NPs (200 ppm) with oleaster leaves essential oil (2000 ppm) resulted in a higher pH value (5.88), total phenolic content (10.45 mg/100 g) and lower TBARS (2.11 mg/kg), and also decreased total viable bacteria (1.28 Log CFU/g), Clostridium perfringens (1.43 Log CFU/g), E. coli (0.24 Log CFU/g), Staphylococcus aureus (0.63 Log CFU/g), and molds and yeasts (0.86 Log CFU/g) count in samples at day 45 in comparison to the control (120 ppm nitrite). The consumers approved sensory traits in nitrite-free formulated sausages containing ε-PL-NPs and Ni-NPs combined with OLEOs.

Changes in Texture Characteristics and Special Requirements of Sichuan-Style Braised Beef for Industrial Production: Based on the Changes in Protein and Lipid of Beef

This study aimed to investigate the optimal stewing time (0, 30, 60, 90, 120, and 150 min) for industrialized preparation of Sichuan-style braised beef with different demands. With prolonged stewing time, the hardness and chewiness of the braised beef initially increased and then decreased (p < 0.05), whereas springiness and cohesiveness gradually decreased. The moisture content of braised beef and the endogenous fluorescence intensity of braised beef protein significantly decreased (p < 0.05). However, the thiobarbituric acid reaction substances (TBARS) value and protein carbonyl content of braised beef greatly increased (p < 0.05). During the stewing process, the texture properties of Sichuan-style braised beef were affected by the moisture content, oxidation of proteins and lipids, and integrity of the muscle fibers. Considering texture traits, when Sichuan-style pre-braised beef bought by consumers is stewed with other ingredients for about 30 min, its corresponding stewing time is 60 min in industrialized production processes. This process parameter can not only save energy consumption for practical production, but also improve the hardness value of the as-obtained Sichuan-style pre-braised beef, which is conducive to transportation through refraining from cracking of pre-braised beef pieces. When consumers only use simple heating to eat the Sichuan-style pre-braised beef product, stewing times of 120 or 150 min can be considered in industrialized production processes. This work provided a theoretical reference for the industrialized and standardized production of different types of prepared Sichuan-style braised beef.

Effects of ellagic acid and ε-polylysine hydrochloride on the content of biogenic amines, volatile compounds and quality of salmon slices during chilled storage

This study aimed to investigate effects of ellagic acid (EA) and ε-polylysine hydrochloride (ε-PL) on biogenic amines (BAs), volatile compounds and quality of salmon slices stored at 4 °C. The results showed that EA and ε-PL attenuated the production of BAs, retarded the increase of TVC, TVB-N and TBARS. Additionally, water mobility, texture properties of salmon slices were also stabilized by the EA and ε-PL. Volatile compounds including aldehydes, alcohols and hydrocarbons were identified and spoilage-related compounds reduced by the EA and ε-PL, which was related to the inhibition of bacterial, TVB-N and TBA growth by EA and ε-PL. The content of phencthylamine, putrescine, cadaverine, histamine and tyramine in EA-s-PL groups reduced by 46.53%, 54.1%, 26.42%, 31.98% and 45.37% compared to the control group at the end of storage, respectively. Therefore, EA and ε-PL can be applied for inhibiting the increase of BAs and delaying quality deterioration of salmon slices.

Nanoemulsion-based approach to preserve muscle food: A review with current knowledge

Muscle foods are regarded as nutritionally dense foods while they are prone to spoilage by action of microorganism and oxidation. Recently, the consumer's preference is mostly toward minimally processed foods as well as preserved with natural preservatives. However, natural extract directly to the food matrix has several drawbacks. Hence development and applications of nanoemulsion has gained importance for the preservation of muscle foods to meet consumer requirements with enhanced food safety. Nanoemulsion utilizes natural extracts at much lower concentration with higher preservative abilities over original components. Nanoemulsions offer protection to the active component from degradation and ensure longer bioavailability. Novel techniques used for formulation of nanoemulsion provide stability to the emulsion with desirable qualities to improve their impacts. The application of nanoemulsion is known to enhance the preservative action of nanoemulsions by improving the microbial safety and oxidative stability in nanoform. This review provides recent updates on different methods used for formulation of nanoemulsions from different sources. Besides, successful application of nanoemulsion derived using natural agents for muscle food preservation and shelf life extension are reviewed. Thus, the application of nanoemulsion to extend shelf life and maintain quality is suggested for muscle foods.

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.

Recent Developments and Applications of Nanosystems in the Preservation of Meat and Meat Products

Due to their high water, lipid, and protein content, meat and meat products are highly perishable. The principal spoilage mechanisms involved are protein and lipid oxidation and deterioration caused by microbial growth. Therefore, efforts are ongoing to ensure food safety and increase shelf life. The development of low-cost, innovative, eco-friendly approaches, such as nanotechnology, using non-toxic, inexpensive, FDA-approved ingredients is reducing the incorporation of chemical additives while enhancing effectiveness and functionality. This review focuses on advances in the incorporation of natural additives that increase the shelf life of meat and meat products through the application of nanosystems. The main solvent-free preparation methods are reviewed, including those that involve mixing organic–inorganic or organic–organic compounds with such natural substances as essential oils and plant extracts. The performance of these additives is analyzed in terms of their antioxidant effect when applied directly to meat as edible coatings or marinades, and during manufacturing processes. The review concludes that nanotechnology represents an excellent option for the efficient design of new meat products with enhanced characteristics.

Application of a Newly Developed Chitosan/Oleic Acid Edible Coating for Extending Shelf-Life of Fresh Pork

This study aimed at evaluating the applicability of a newly-developed chitosan/oleic acid edible coating for extending the shelf-life of fresh pork under aerobic-packaging conditions. Various coating formulations were used: 2% chitosan alone (CHI), 0.5% (v/v) oleic acid in 2% chitosan (CHI/0.5%OA) and 1% (v/v) oleic acid in 2% chitosan (CHI/1%OA) were prepared. For coating, fresh pork slices were fully immersed in the coating solutions for 30 s and dried naturally at 4 °C for 30 min. The coated samples were placed on trays, over-wrapped with plastic film, stored at 4 °C for 21 days, and were analyzed for shelf-life stability. Samples without coating were used as control. It was found that the aerobic bacteria and Pseudomonas spp. counts, and total volatile basic nitrogen (TVBN) content were almost two to three times lower in the CHI/OA-coated samples compared to the control after 21 days of storage (p < 0.05). The CHI/OA coating combination completely inhibited growth of E. coli, and protected the meat from discoloration after 21 days of storage. In particular, the addition of OA increased the concentration of volatiles associated with pleasant aromas. This study provides an application potential of chitosan/oleic acid edible coating in preservation of fresh pork to prolong the shelf-life and improve safety.

Antioxidant and Antimicrobial Biofoil Based on Chitosan and Japanese Knotweed (Fallopia japonica, Houtt.) Rhizome Bark Extract

A 70% ethanol_(aq) extract of the rhizome bark of the invasive alien plant species Japanese knotweed (JKRB) with potent (in the range of vitamin C) and stable antioxidant activity was incorporated in 1% w/v into a chitosan biofoil, which was then characterized on a lab-scale. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay confirmed the antioxidant activity of the JKRB biofoil upon contact with the food simulants A, B, C, and D1 (measured half-maximal inhibitory concentrations—IC₅₀) and supported the Folin–Ciocalteu assay result. The migration of the antioxidant marker, (−)-epicatechin, into all food simulants (A, B, C, D1, D2, and E) was quantified using liquid chromatography hyphenated to mass spectrometry (LC-MS). Calculations showed that 1 cm² of JKRB biofoil provided antioxidant activity to ~0.5 L of liquid food upon 1 h of contact. The JKRB biofoil demonstrated antimicrobial activity against Gram-positive bacteria. The incorporation of JKRB into the chitosan biofoil resulted in improved tensile strength from 0.75 MPa to 1.81 MPa, while elongation decreased to 28%. JKRB biofoil’s lower moisture content compared to chitosan biofoil was attributed to the formation of hydrogen bonds between chitosan biofoil and JKRB compounds, further confirmed with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The JKRB biofoil completely degraded in compost in 11 days. The future upscaled production of JKRB biofoil from biowastes for active packaging may support the fights against plastic waste, food waste, and the invasiveness of Japanese knotweed, while greatly contributing to the so-called ‘zero-waste’ strategy and the reduction in greenhouse gas emissions.

Preparation of sodium alginate/konjac glucomannan active films containing lycopene microcapsules and the effects of these films on sweet cherry preservation

In this study, lycopene microcapsules (LMs) were prepared using chitosan (CS) and carboxymethyl CS (CMCS) as the wall materials. Sodium alginate (SA) and konjac glucomannan (KGM) were used as substrates to fabricate LM/SA/KGM composite films. Results showed that when 2.0 % CMCS was employed, the resulting LMs had the maximum embedding rate of 83.17 %, smallest particle sizes, and stable zeta potentials. The LMs still had a high retention rate after 10 days of storage at 4 and 25 °C. When 2.0 % LMs were used, the corresponding composite film exhibited the best antibacterial properties, oxidation resistance, a high transparency (82.3 %), and a strong water vapor barrier (2.39 × 10^-10 g/m·s·Pa). Finally, the effects of the as-prepared composite films on the preservation of sweet cherries stored at 0 °C for 15 days were investigated. The results indicated that the LM/SA/KGM composite film effectively prolonged the shelf lives of sweet cherries and efficiently delayed the decline in the decay rate, pH, contents of soluble solids, and other indicators. The application of LM/SA/KGM composite films in fruit and vegetable preservation has development prospects and provides a reference for expanding the application range of lycopene and enhancing fruit and vegetable preservation.

Antibacterial aerogels with nano‑silver reduced in situ by carboxymethyl cellulose for fresh meat preservation

Bacterial cellulose (BC) was used as a reinforcing agent, citric acid (CA) as a cross-linking agent, and CMC@AgNPs as antibacterial nanomaterials, in which CMC@AgNPs were reduced from AgNO₃ in situ by carboxymethyl cellulose (CMC) as a reducing agent and stabilizer to fight microbial corruption. Its potential application in packaging fresh meat has been investigated. Results showed that the antibacterial CMC@AgNPs/BC/CA aerogels with excellent structural integrity and outstanding water absorption were developed by adding 0.3% BC and 0.25% CA. The CMC@AgNPs/BC/CA aerogel significantly reduced the color change and the total viable bacterial counts (TVC) in fresh meat after 7 days of refrigerated storage. The results indicated that CMC@AgNPs/BC/CA aerogels can effectively extend the shelf life of fresh meat, and can be used for meat packaging as a biologically active absorption pad.

Plant protein-based nanocomposite films: A review on the used nanomaterials, characteristics, and food packaging applications

Consumer demands to utilize environmentally friendly packaging have led researchers to develop packaging materials from naturally derived resources. In recent years, plant protein-based films as a replacement for synthetic plastics have attracted the attention of the global food packaging industry due to their biodegradability and unique properties. Biopolymer-based films need a filler to show improved packaging properties. One of the latest strategies introduced to food packaging technology is the production of nanocomposite films which are multiphase materials containing a filler with at least one dimension less than 100 nm. This review provides the recent findings on plant-based protein films as biodegradable materials that can be combined with nanoparticles that are applicable to food packaging. Moreover, it investigates the characterization of nanocomposite plant-based protein films/edible coatings. It also briefly describes the application of plant-based protein nanocomposite films/coating on fruits/vegetables, meat and seafood products, and some other foods. The results indicate that the functional performance, barrier, mechanical, optical, thermal and antimicrobial properties of plant protein-based materials can be extended by incorporating nanomaterials. Recent reports provide a better understanding of how incorporating nanomaterials into plant protein-based biopolymers leads to an increase in the shelf life of food products during storage time.

Development and characterization of levan/pullulan/chitosan edible films enriched with ε-polylysine for active food packaging

The levan/pullulan/chitosan edible films, enriched with ε-polylysine, as an antimicrobial agent, were successfully fabricated by the casting method, and their applicability for food packaging was systematically evaluated by several analytical techniques. An increase in the levan/pullulan ratios (ranged from 0:6 to 3:3) in the films showed a decreased water solubility (from 72.21% to 26.64%) and oxygen permeability (from 48.75 × 10^-2 g·mm·m^-2·d^-1·kPa^-1 to 4.45 × 10^-2 g·mm·m^-2·d^-1·kPa^-1), and increased elongation at break (from 10.92% to 46.61%). All the films showed a strong inhibitory effect on two typical food-borne pathogens and good biodegradability in the soil. These films were employed as edible coatings on strawberries, and the storage stability was investigated by means of physical and biochemical parameters. Compared to control, the weight loss, firmness, and total soluble solids of the coated strawberries showed a downward trend. Overall, these findings suggest that the developed edible films could be a potential approach for sustainable active food packaging.

Advancements in Biodegradable Active Films for Food Packaging: Effects of Nano/Microcapsule Incorporation

Food packaging plays a fundamental role in the modern food industry as a main process to preserve the quality of food products from manufacture to consumption. New food packaging technologies are being developed that are formulated with natural compounds by substituting synthetic/chemical antimicrobial and antioxidant agents to fulfill consumers’ expectations for healthy food. The strategy of incorporating natural antimicrobial compounds into food packaging structures is a recent and promising technology to reach this goal. Concepts such as “biodegradable packaging”, “active packaging”, and “bioactive packaging” currently guide the research and development of food packaging. However, the use of natural compounds faces some challenges, including weak stability and sensitivity to processing and storage conditions. The nano/microencapsulation of these bioactive compounds enhances their stability and controls their release. In addition, biodegradable packaging materials are gaining great attention in the face of ever-growing environmental concerns about plastic pollution. They are a sustainable, environmentally friendly, and cost-effective alternative to conventional plastic packaging materials. Ultimately, a combined formulation of nano/microencapsulated antimicrobial and antioxidant natural molecules, incorporated into a biodegradable food packaging system, offers many benefits by preventing food spoilage, extending the shelf life of food, reducing plastic and food waste, and preserving the freshness and quality of food. The main objective of this review is to illustrate the latest advances in the principal biodegradable materials used in the development of active antimicrobial and antioxidant packaging systems, as well as the most common nano/microencapsulated active natural agents incorporated into these food-packaging materials.

A Review of Nonbiodegradable and Biodegradable Composites for Food Packaging Application

The dependency on nonbiodegradable-based food packaging, increase in population growth, and persistent environmental problems are some of the driving forces in considering the development of biodegradable food packaging. This effort of green packaging has the potential to solve issues on plastic wastes through the combination of biodegradable composite-based food packaging with plant extracts, nanomaterials, or other types of polymer. Modified biodegradable materials have provided numerous alternatives for producing green packaging with mechanical strength, thermal stability, and barrier performance that are comparable to the conventional food packaging. To the best of our knowledge, the performance of nonbiodegradable and biodegradable composites as food packaging in terms of the above properties has not yet been reviewed. In this context, the capability of biodegradable polymers to substitute the nonbiodegradable polymers was emphasized to enhance the packaging biodegradation while retaining the mechanical strength, thermal stability, barrier properties, and antioxidant and antimicrobial or antibacterial activity. These are the ultimate goal in the food industry. This review will impart useful information on the properties of food packaging developed from different polymers and future outlook toward the development of green food packaging.

Antibacterial mechanism of linalool emulsion against Pseudomonas aeruginosa and its application to cold fresh beef

Pseudomonas aeruginosa (P. aeruginosa) is the dominant spoilage bacterium in cold fresh beef. The current strategy is undertaken to overcome the low water solubility of linalool by encapsulating linalool into emulsions. The results of field emission scanning electron microscopy and particle size distribution revealed that the appearance of the bacterial cells was severely disrupted after exposure to linalool emulsion (LE) with an minimum inhibitory concentration (MIC) of 1.5 mL/L. Probes combined with fluorescence spectroscopy were performed to detect cell membrane permeability, while intracellular components (protein and ion leakage) and crystal violet staining were further measured to characterize cell membrane integrity and biofilm formation ability. The results confirmed that LE could destroy the structure of the cell membrane, thereby leading to the leakage of intracellular material and effective removal of biofilms. Molecular docking confirmed that LE can interact with the flagellar cap protein (FliD) and DNA of P. aeruginosa, inhibiting biofilm formation and causing genetic damage. Furthermore, the results of respiratory metabolism and reactive oxygen species (ROS) accumulation revealed that LE could significantly inhibit the metabolic activity of P. aeruginosa and induce oxidative stress. In particular, the inhibition rate of LE on P. aeruginosa was 23.03% and inhibited mainly the tricarboxylic acid cycle (TCA). Finally, LE was applied to preserve cold fresh beef, and the results showed that LE could effectively inhibit the activity of P. aeruginosa and delay the quality change of cold fresh beef during the storage period. These results are of great significance to developing natural preservatives and extending the shelf life of cold fresh beef.

Recent advances in extraction, modification, and application of chitosan in packaging industry

Current environmental concerns fostered a strong interest in extracting polymers from renewable feedstocks. Chitosan, a second most abundant polysaccharide after cellulose, may prove to be a promising green material owing to its renewability, inherent biodegradablity, natural availability, non-toxicity, and ease of modification. This review is intended to comprehensively overview the recent developments on the isolation of chitosan from chitin, its modification and applications as a reinforcing candidate for food packaging materials, emphasizing the scientific underpinnings arising from its physicochemical properties, antimicrobial, antioxidant, and antifungal activities. We review various chitosan-reinforced composites reported in the literature and comprehensively present intriguing mechanical and other functional properties. We highlight the contribution of these mechanically robust and responsive materials to extend the shelf-life and maintain the qualities of a wide range of food commodities. Finally, we assess critical challenges and highlight future opportunities towards understanding the versatile applications of chitosan nanocomposites.

Physicochemical properties of films produced using nanoemulsions stabilized by carboxymethyl chitosan-peptide conjugates and application in blueberry preservation

Carboxymethyl chitosan (CMCh)-peptide conjugates were produced by grafting CMCh with peptides from hemp seed, maize and casein. The nanoemulsions stabilized by these conjugates had smaller droplet size and better emulsifying properties. Nanoemulsions stabilized by conjugates were used to develop active films containing Camellia essential oil and the effect of conjugation on physicochemical properties of resulting films was evaluated. Water vapor and oxygen barrier properties, tensile strength, flexibility, and temperature of endothermic peak increased 6.6-19.8% and 6.9-27.2%, 40.1-96.6%, 61.4-83.3% and 7.8-18.5%, respectively when the CMCh-peptide conjugates were used to emulsify the essential oil. The conjugation helped to form compact structure. All of the films containing essential oil emulsions stabilized by conjugates showed the ability to extend the shelf-life of blueberry by maintaining the firmness, reducing the weight loss and slowing down the formation of soluble solids.

Green Coating Polymers in Meat Preservation

Edible coatings, including green polymers are used frequently in the food industry to improve and preserve the quality of foods. Green polymers are defined as biodegradable polymers from biomass resources or synthetic routes and microbial origin that are formed by mono- or multilayer structures. They are used to improve the technological properties without compromising the food quality, even with the purpose of inhibiting lipid oxidation or reducing metmyoglobin formation in fresh meat, thereby contributing to the final sensory attributes of the food and meat products. Green polymers can also serve as nutrient-delivery carriers in meat and meat products. This review focuses on various types of bio-based biodegradable polymers and their preparation techniques and applications in meat preservation as a part of active and smart packaging. It also outlines the impact of biodegradable polymer films or coatings reinforced with fillers, either natural or synthesized, via the green route in enhancing the physicochemical, mechanical, antimicrobial, and antioxidant properties for extending shelf-life. The interaction of the package with meat contact surfaces and the advanced polymer composite sensors for meat toxicity detection are further considered and discussed. In addition, this review addresses the research gaps and challenges of the current packaging systems, including coatings where green polymers are used. Coatings from renewable resources are seen as an emerging technology that is worthy of further investigation toward sustainable packaging of food and meat products.