Chitosan based coatings extend the shelf-life of beef slices during refrigerated storage

Chitosan-pullulan edible coating loaded with dihydromyricetin: Enhanced antioxidant activity and barrier properties to prolong Cantonese sausages' shelf-life

Cantonese sausages are susceptible to oxidative deterioration during storage. Compared with synthetic antioxidants, dihydromyricetin (DMY) is a natural active substance with various functions such as antioxidant and antimicrobial. In this study, edible coating solutions loaded with DMY were prepared based on chitosan (CS) and pullulan (PUL) to prolong the shelf-life of Cantonese sausages. FT-IR and XRD results showed good compatibility between DMY and CS-PUL. It was found that 8 % DMY was physically cross-linked with CS and PUL mainly through hydrogen bonding, which enhanced the barrier and mechanical properties of the films. Meanwhile, the antioxidant property, antimicrobial efficiency and thermal stability of the films were also significantly improved (p < 0.05). The results of storage experiments of Cantonese sausages showed that the 8 % DMY-CP coating solution could effectively retard the lipid oxidation of Cantonese sausages at 25 °C, and maintain the appearance and flavour of products at storage on the 28th d. This study proved DMY's potential as a natural alternative to synthetic additives in polysaccharide-based edible coatings, providing a green and sustainable solution to combat lipid oxidation in meat products.

Fabrication and Characterization of Buforin I-Loaded Electrospun Chitosan/Polyethylene Oxide Nanofibrous Membranes with Antimicrobial Activity for Food Packing Applications

The rising resistance of bacteria to antibiotics has driven the search for new antimicrobial agents. This study focused on encapsulating Buforin I, an antimicrobial peptide, in chitosan/polyethylene oxide (CS-PEO) nanofibers. Buforin I was loaded at a minimum bactericidal concentration (MBC), 10× MBC, and 20× MBC, with assessments on morphology, thermal properties, chemical bonds, crystalline structure, mechanical strength, antimicrobial activity, and cell toxicity. Techniques like differential scanning calorimetry and Fourier-transform infrared spectroscopy confirmed the effective loading of Buforin I in the nanofibers. Scanning electron microscopy showed that Buforin incorporation increased nanofiber diameters. The tensile strength peaked at 20× MBC. Microbial tests indicated that the inhibition zone for nanofibers at 20× MBC surpassed that of commercial antibiotics. Beef coated with CS-PEO nanofibers containing Buforin I demonstrated reduced pH and water activity, alongside lower weight loss during storage. Texture and color analyses revealed that the Buforin I nanofibers helped maintain beef hardness and slowed color degradation compared to control samples. Moreover, thiobarbituric acid levels and total microbial counts in the coated beef were significantly lower than controls (below 3 log CFU/g after 9 days at 4 °C). Thus, these nanofibers may serve as effective antimicrobial packaging agents to delay food spoilage.

Antibacterial activity of polyethylene film by hyperthermal hydrogen induced cross-linking with chitosan quaternary ammonium salt

In this study, hyperthermal hydrogen-induced cross-linking (HHIC) technology was applied to construct a dense cross-linking layer of antibacterial chitosan quaternary ammonium salt (HTCC) to PE surface through the selective cleavage of CH bonds and subsequent cross-linking of the resulting carbon radicals. Before HHIC treatment, UV-Ozone was used to activate PE surface to facilitate HTCC adsorption. FT-IR and XPS analyses proved the successful cross-linking between PE and HTCC. From AFM analysis, the prepared PE cross-linked HTCC film (PE-c-HTCC) showed the rougher surface with average roughness (Ra) of 9.16 nm. The water vapor permeability (WVP) and oxygen permeability (OP) values of the film were decreased by about 83 % and 97 %, respectively. Additionally, the film exhibited strong antibacterial properties against E. coli and S. aureus. In terms of these properties, the shelf life of fresh beef could be extended for 2 days after packing with the PE-c-HTCC film.

Exogenous Ergothioneine and Glutathione Limit Postharvest Senescence of Arugula

Arugula is susceptible to postharvest deterioration. We tested the impact of exogenous antioxidant (i.e., ergothioneine and glutathione) dip solutions on arugula quality during storage at 4 °C or 10 °C for up to 17 days relative to a non-antioxidant treatment. Leaves from each dip treatment and storage temperature were assessed for visual quality and endogenous antioxidant metabolite profiles. Overall, leaf discolouration, wilting, and decay were more rapid at 10 °C than at 4 °C. Both antioxidant treatments limited leaf discolouration at 4 °C. Exogenous ergothioneine reduced wilting at 4 °C, whereas exogenous glutathione limited the incidence of leaf decay. At 10 °C, glutathione reduced the incidence of discolouration and decay, whereas both antioxidant dip treatments limited the decline in leaf yellowing. Ergothioneine was solely detected in ergothioneine-treated leaves; a decrease occurred within the first two days of storage but was unchanged thereafter. Although both antioxidant treatments did not affect endogenous glutathione concentrations at either storage temperature, glutathione disulfide was stable within the glutathione-treated leaves, whereas it increased in the other treatments. Ascorbate degradation was delayed in ergothioneine-treated leaves at 4 °C relative to all other treatments, whereas both antioxidant treatments little affected ascorbate metabolism in leaves stored at 10 °C.

The effect of pomegranate peel extract added as a natural preservative on the quality parameters of thornback ray (Raja clavata) sausages stored at +4°C

In this study, three different groups of sausages were produced from thornback ray (Raja clavata) without additives (control group), waste pomegranate peel extract (natural group), and ascorbic acid (synthetic group). Biochemical, physicochemical, and microbiological changes of sausages were examined under refrigerator conditions (+4°C), and the shelf life was determined. The best results in terms of nutritional and physicochemical values were obtained in sausages treated with pomegranate peel extract. All sausage groups were spoiled on the 15th day in terms of the total volatile basic nitrogen (TVB-N); however, the pomegranate peel extract group showed a more positive effect compared to the other sausage groups. However, this value was not considered because cartilaginous fish such as stingrays contain higher levels of nonprotein nitrogenous compounds. It was observed that microbial growth was less in the natural group and the antimicrobial effect of pomegranate peel extract was higher than that of ascorbic acid. In addition, it was determined that the pomegranate peel extract group extended the shelf life up to 6 days in terms of total viable count (TVC) and yeast/mold compared to the control and synthetic groups, respectively. This study showed that pomegranate peel extract has a better protective effect than ascorbic acid and it can be used as a natural additive in preserving the quality of seafood products.

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.

Combined Effect of an Active AgIon® Absorbent Pad and a Chitosan Coating on the Preservation of Fresh Beef

In the present study, the combined effect of an AgIon® antimicrobial absorbent (Ζ) pad and a chitosan coating (C) on the preservation of fresh beef stored aerobically at 5 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored for up to 10 days of storage. The microbiological data indicated that the C and chitosan coating plus absorbent pad (CZ) treatments were the most efficient in reducing total viable counts (TVC) by 4.09 and 3.53 log cfu/g compared to the control W and Z treatments on day 4 of storage (p < 0.05). An analogous reduction in the counts of the other microbial groups monitored was recorded. pH values were ca. 5.7 for treatments W and Z and 5.45 for treatments C and CZ on day 4 of storage (p < 0.05). The total volatile basic nitrogen (TVB-N) values remained <20 mg/100 g for all treatments on day 4 and for treatments C and CZ on day 10 of storage. The total color difference values decreased (p < 0.05) during storage for treatments W and Z, but remained constant for treatments C and CZ. Based on sensory, microbiological and physico-chemical data, beef shelf life was ca ^# + 3 days for samples W and Z and at least 10 + 3 days for samples C and CZ. Between the two antimicrobial treatments, chitosan was considerably more effective than the AgIon® antimicrobial absorbent pad, which showed practically no antimicrobial activity in direct contact with beef meat.

Development and characterization of smart double-layer nanofiber mats based on potato starch-turnip peel anthocyanins and guar gum-cinnamaldehyde

This experiment was conducted with the objectives of developing bilayer nanofiber mats based on potato starch-turnip peel extract (PS-TPE) and guar gum-cinnamaldehyde (GG-CA) for freshness monitoring and enhancing the quality of lamb meat during cooled storage conditions. Encapsulating CA/TPE into the nanofibers resulted in reduced tensile strength, water vapor permeability, moisture content, and water solubility. Colorimetric nanofibers, including PS-GG-TPE 6%, PS-GG-TPE 6%-CA 0.5%, and PS-GG-TPE 6%-CA 1%, presented red color at pH 1-4, purplish red at pH 5-7, green at pH 8-10, and brown at pH 11-12. The color of PS-GG-TPE 6% nanofiber mats changed from white to purplish red, signaling that the lamb meats had turned from fresh to spoiled. PS-GG-CA 1%, PS-GG-TPE 6%-CA 0.5%, and PS-GG-TPE 6%-CA 1% nanofibers have the potential to be utilized to control the growth of spoilage-related microorganisms for extending the shelf-life of fresh lamb meat under cooled storage conditions up to 13 days.

Impacts of Selenium-Chitosan Treatment on Color of "Red Globe" Grapes during Low-Temperature Storage

Maintaining the vibrant color of fruit is a longstanding challenge in fruit and vegetable preservation. Chitosan and selenium, known for their protective and antioxidant properties, have been applied to preserve these produce. This study aimed to investigate the influence of selenium-chitosan treatment (comprising 25 mg L-1 selenium and 1.0% chitosan) on the color of "Red Globe" grapes and to analyze the relative expression of genes associated with anthocyanin synthesis enzymes (VvCHS, VvCHI, VvF3H, VvF3'H, VvF3'5'H, VvDFR, VvLDOX, VvUFGT, VvOMT, Vv5GT, and VvGST) using RT-qPCR. Our goal was to uncover the regulatory mechanisms governing grape color. Comparing various treatments, we observed that selenium-chitosan treatment had a significant effect in reducing decay, maintaining the soluble solids content of grape flesh, and preserving the vivid color of grape. This research indicated that selenium-chitosan treatment slowed down browning and prevented the reduction in total phenolic, flavonoids, and anthocyanin in the grape. Moreover, gene expression analysis revealed that selenium-chitosan treatment increased the expression of VvCHS, VvF3H, VvF'3'H, VvLDOX, and Vv5GT, while also stabilized the expression of VvCHI, VvF3'H, and VvDFR in grape skins. These findings shed light on the potential mechanism by which selenium-chitosan impacts grape color. This study established a theoretical foundation for investigating the molecular mechanisms behind selenium-chitosan's ability to slow down grape browning and provides a novel approach to enhancing fruit and vegetable preservation techniques.

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 impact of freezing methods on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton during long-term frozen storage

The aim of present study was to investigate the influence of conventional freezing (CF, -18 °C), low-temperaturefreezing (LF, -40 °C), and ultra-low-temperature freezing (ULF, -80 °C) on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton (HGM) during frozen storage (0, 30, 60, 90, 120, 150 and 180 days). The TPC, TVB-N, and TBARS values increased significantly with prolonged storage, while the moisture content decreased (P < 0.05). Additionally, the concentrations of aldehydes, alcohols, ketones, acids, and alkenes decreased significantly as the storage duration increased. However, the concentrations of esters and heterocyclics increased (P < 0.05). Notably, at 30-180 days of storage, the TBARS and TVB-N values in ULF samples were significantly lower than those in CF and LF samples, while the moisture content was significantly higher (P < 0.05). Low field-nuclear magnetic resonance (LF-NMR) analysis showed that ULF decreased water migration and maintained the original texture characteristics of HGM during frozen storage. The ULF and LF groups had significantly higher levels of volatiles than the CF group (P < 0.05). The findings show that ULF, with its relatively rapid freezing rates, can still maintain the high quality of HGM after 180 days of frozen storage, contributing to quality control.

Preparation of Complementary Food for Infants and Young Children with Beef Liver: Process Optimization and Storage Quality

In this study, fuzzy mathematics and response surface modeling were applied to optimize the preparation process of beef liver paste and characterize the proximate composition, sensory and physicochemical qualities, and in vitro simulated digestive properties while refrigerated at 0-4 °C (0, 3, 7, 15, 30, 45, and 60 days). The results showed that the optimal preparation process was 4.8% potato starch, 99.4% water, 10.2% olive oil, and a 3:2 ratio of chicken breast and beef liver. The beef liver paste prepared contained essential amino acids for infants and children, with a protein content of 10.29 g/100 g. During storage, the pH of the beef liver paste decreased significantly (p < 0.05) on day 7, texture and rheological properties decreased significantly after 30 days, a* values increased, L* and b* values gradually decreased, and TVB-N and TBARS values increased significantly (p < 0.05) on day 7 but were below the limit values during the storage period (TVB-N value ≤ 15 mg/100 g, TBARS value ≤ 1 mg/Kg). In vitro simulated digestion tests showed better digestibility and digestive characteristics in the first 15 days. The results of this study provide a reference for the development of beef liver products for infant and child supplementation.

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.

Olfactory visualization sensor system based on colorimetric sensor array and chemometric methods for high precision assessing beef freshness

Beef is easily spoiled, resulting in foodborne illness and high societal costs. This study proposed a novel olfactory visualization system based on colorimetric sensor array and chemometric methods to detect beef freshness. First, twelve color-sensitive materials were immobilized on a hydrophobic platform to acquire scent information of beef samples according to solvatochromic effects. Second, machine vision algorithms were used to extract the scent fingerprints, and principal component analysis (PCA) was employed to compress the feature dimensions of the fingerprints. Finally, four qualitative models, k-nearest neighbor, extreme learning machine, support vector machine (SVM), and random forest, were constructed to evaluate the beef freshness according to the value of total volatile basic nitrogen (TVB-N) and total viable counts (TVC). Results demonstrated that SVM had a preferable prediction ability, with 95.83% and 95.00% precision in the training and prediction sets, respectively. The results revealed that the simple constructed olfactory visualization sensor system could rapidly, robustly, and accurately assess beef freshness.

Influence of Gelatin-Chitosan-Glycerol Edible Coating Incorporated with Chlorogenic Acid, Gallic Acid, and Resveratrol on the Preservation of Fresh Beef

Chlorogenic acid (CA), gallic acid (GA), and resveratrol (RES) were added to a gelatin (GEL)-chitosan (CHI)-glycerol (GLY) edible coating, and their effects on the coating of fresh beef preservation were investigated. The results revealed that CA had the most significant improvement effect on fresh beef preservation. The combination of GEL-CHI-GLY-CA preserved the color of the beef better and delayed the increase of the total volatile base nitrogen, even though its total phenolic content decreased at a faster rate during beef preservation. GA also improved the preservation effect as on the 12th day of storage, the beef samples treated with GEL-CHI-GLY-GA had the lowest thiobarbituric acid reactive substances (0.76 mg Malondialdehyde (MDA)/kg) and total viable count (6.0 log cfu/g). On the whole, though RES showed an improvement on beef preservation, the improvement was not as good as the other two polyphenols. After 12 days of storage, the beef samples treated with GEL-CHI-GLY-RES had a higher pH value (6.25) than the other two polyphenol treatmed groups. Overall, the three polyphenol-added combinations increased the shelf life of beef by approximately 3-6 days compared to the control group (treated GEL-CHI-GLY with distilled water).

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.

Effects of chitosan-based coatings incorporated with ɛ-polylysine and ascorbic acid on the shelf-life of pork

Chitosan is a food thickener with film-forming ability and antibacterial activity. ɛ-Polylysine is a preservative with broad-spectrum antibacterial activity. Ascorbic acid is a food antioxidant. In this study, pork chunks were treated with four dipping solutions, i.e. purified water (control), 0.2% ascorbic acid (treatment-1), 0.02% ɛ-polylysine (treatment-2), and 0.4% chitosan + 0.02% ɛ-polylysine + 0.2% ascorbic acid (treatment-3), and stored at 3 °C for 12 days. All treatments suppressed bacterial growth, increases in pH and total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances and decreases in the red indices of pork chunks compared with the control during refrigeration. Based on the national standards of total bacterial number and TVB-N of pork, treatment-3 extended the shelf-life of pork chunks by six days compared with the control. The results verified that chitosan-based coatings may be a practical method for the preservation of pork chunks during refrigeration.

A MoS2QDs/chitin nanofiber composite for improved antibacterial and food packaging

Chitin nanofiber has potential application as antibacterial nanocomposite material because of its inherent biocompatibility, biological activity, amino containing macromolecular structure and nano-size effect. Molybdenum disulfide quantum dots (MoS₂QDs) were uniformly bonded on partially deacetylated chitin nanofibers (DEChNs) by hydrothermal reactions. The antibacterial properties of MoS₂QDs/DEChN against Escherichia coli were detected under different conditions. When the antibacterial agent was fixed at 200 μg/mL, the survival rates of bacteria were 2.77% (pH = 4), 5.58% (pH = 5) and 7.83% (pH = 6), which were lower than those in the DEChN groups. Unlike DEChN, which only had excellent antibacterial activity under acidic conditions (pH < 5), the combination of DEChN and MoS₂QDs had antibacterial activity close to neutral conditions, with a bacteriostatic rate > 90%. When TEMPO-oxidized cellulose nanofibers (TOCN) were applied for the preparation of MoS₂QDs/TOCN, they did not show obvious antibacterial ability, which proved the positive role of DEChN and its amino groups. The MoS₂QDs/DEChN assembled film could be applied to preserve meat by delaying spoilage. The current study might inspire new ideas for designing food packaging based on the prepared MoS₂QDs/DEChN films.

A Novel Class IIb Bacteriocin-Plantaricin EmF Effectively Inhibits Listeria monocytogenes and Extends the Shelf Life of Beef in Combination with Chitosan

Plantaricin EmF separated and identified from L. plantarum 163 was a novel class IIb bacteriocin. The molecular masses of plantaricin Em and F were 1638 and 3702 Da, respectively, with amino acid sequences FNRGGYNFGKSVRH and VFHAYSARGVRNNYKSAVGPADWVISAVRGFIHG, respectively. Plantaricin EmF not only exhibited broad-pH adaptability and thermostability but also showed high efficiency and broad-spectrum antibacterial activity. Its mode of action on L. monocytogenes damaged cell membrane integrity, resulting in the leakage of cytoplasm, changes in cell structure and morphology, and ultimately cell death. Additionally, plantaricin EmF inactivated L. monocytogenes in beef, effectively improving the quality indices of beef, thereby extending its shelf life, especially in combination with chitosan. Plantaricin EmF + 1.0% chitosan extended the shelf life of beef to 15 d, demonstrating its potential application value to replace chemical preservatives to control food-borne pathogenic microorganisms and extend the shelf life of meat and meat products in agriculture and the food industry.

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.

Coating with chitosan containing lauric acid (C12:0) significantly extends the shelf-life of aerobically - Packaged beef steaks during refrigerated storage

The present research aimed at investigating the application potential of a newly developed chitosan/lauric acid edible coating in preservation of fresh beef under refrigerated storage and aerobic packaging conditions. The 2-cm thick steaks were coated with 2% chitosan (CHI), 1 mM lauric acid in 2% chitosan (CHI/1 mM LA) or 3 mM lauric acid in 2% chitosan (CHI/3 mM LA), and over-wrapped in permeable film. Non-coated samples were used as a control (CON). Results showed that the inhibitory effects against the spoilage bacteria growth, volatile basic nitrogen formation and lipid oxidation of the chitosan coating was increased with the incorporation of lauric acid (p˂0.05). More importantly, the incorporation of lauric acid almost completely protected the meat samples against the discoloration after 21 days of storage. The coating with chitosan or chitosan/lauric acid completely inhibited the formation of bacterial spoilage-derived volatile compounds. Overall, coating of chitosan containing 1-3 mM lauric acid could be a promising method in preservation of fresh beef to improve safety and quality under aerobic packaging condition.

Effects of Peppermint Extract and Chitosan-Based Edible Coating on Storage Quality of Common Carp (Cyprinus carpio) Fillets

Edible coatings have recently been developed and applied to different food matrices, due to their numerous benefits, such as increasing the shelf life of foods, improving their appearance, being vehicles of different compounds, such as extracts or oils of various spices that have antioxidant and antimicrobial activity, as well as being friendly to the environment. The objective of this research was to develop a new edible coating based on chitosan enriched with peppermint extract and to evaluate its effectiveness to inhibit microbial development in vitro and improve both the quality and shelf life of common carp (Cyprinus carpio) during refrigerated storage (4 ± 1 °C). Three treatments were used: edible coating (C + EC), edible coating +, 5% chitosan (C + ECCh) and edible coating + 1.5% chitosan + 10% peppermint (C + ECChP). Prior the coating carp fillets; the antibacterial activity and antioxidant capacity were evaluated in the peppermint extract and coating solutions. After coating and during storage, the following were determined on the fillet samples: microbiological properties, observed for ECP, an inhibition halo of 14.3 mm for Staphylococcus aureus, not being the case for Gram-negative species, for ECCh, inhibition halos of 17.6 mm, 17.1 mm and 16.5 mm for S. aureus, Salmonella typhimurium and Escherichia coli, respectively; for the ECChP, inhibition halos for S. aureus, S. typhimurium and E. coli of 20 mm, 17 mm and 16.8 mm, respectively. For the physicochemical characteristics: an increase in solubility was observed for all treatments during storage, reaching 46.7 mg SN protein/mg total protein for the control, and values below 29.1 mg SN protein/mg total protein (p < 0.05), for fillets with EC (C + EC > C + ECCh > C + ECChP, respectively at the end of storage. For the pH, maximum values were obtained for the control of 6.4, while for the fillets with EC a maximum of 5.8. For TVB-N, the fillets with different CE treatments obtained values (p < 0.05) of 33.3; 27.2; 25.3 and 23.3 mg N/100 g (control > C + E C > C + ECCh > C + ECChP respectively). Total phenolic compounds in the aqueous peppermint extract were 505.55 mg GAE/100 g dried leaves, with 98.78% antioxidant capacity in the aqueous extract and 81.88% in the EC. Biomolecule oxidation (hydroperoxide content) had a significant increase (p < 0.05) in all treatments during storage, 1.7 mM CHP/mg protein in the control, to 1.4 in C + EC, 1.27 in C + ECCh and 1.16 in C + ECChP; TBARS assay values increased in the different treatments during refrigerated storage, with final values of 33.44, 31.88, 29.40 and 29.21 mM MDA/mg protein in the control; C + EC; C + ECCh and C + ECChP respectively. In SDS -PAGE a protective effect was observed in the myofibrillar proteins of fillets with ECChP). The results indicate that the C + ECCh and C + ECChP treatments extend the shelf life of 3–5 days with respect to microbiological properties and 4–5 days with respect to physicochemical characteristics. A reduction in lipid and protein oxidation products was also observed during refrigerated storage. With these findings, this is considered a promising method to increase the shelf life of fish fillets combined with refrigeration and we are able to recommend this technology for the fish processing industry.