Effect of tannic acid-grafted chitosan coating on the quality of fresh pork slices during cold storage

Properties of modified chitosan-based films and coatings and their application in the preservation of edible mushrooms: A review

Edible mushrooms are prone to deteriorate during storage. A Single chitosan film or coating has limitations in preservation. Therefore, this article focused on the improvement of modified chitosan-based films and coatings on properties related to storage quality of edible mushrooms (e.g.: safety, barrier, mechanical, antioxidant and antibacterial properties). Besides, the application of chitosan-based materials in the preservation of mushrooms was also discussed. The modified chitosan film and coating can slow down the respiration of mushrooms, inhibit the growth of microorganisms, protect antioxidant compositions, and regulate the activity of related enzymes, thus improving the quality and prolonging the shelf life of mushrooms. Meanwhile, the added ingredients improve the water and gas barrier properties of chitosan through volume and group occupation, and reduce the light transmittance of chitosan through light transmission, scattering and absorption. Essential oils and polyphenolic compounds had a better enhancement of antioxidant and antimicrobial properties of chitosan.

Characterization of sodium alginate-carrageenan films prepared by adding peanut shell flavonoids as an antioxidant: Application in chilled pork preservation

This study prepared and characterized sodium alginate and carrageenan (SAC) composite films incorporated with peanut shell flavonoids (PSFs). PSFs compound identification research was implemented. The physicochemical features of PSFs-SAC composite films and their ability to preserve chilled pork in a 4 °C refrigerator were determined. PSFs consist of luteolin, eriodictyol, 5,7-dihydroxychromone, and 8 other components. They significantly improved the mechanical properties, barrier properties, thermal stability, and antioxidant properties of SAC composite films (P < 0.05). PSFs were also responsible for increasing the density of the film structure between the sodium alginate and carrageenan molecules. During storage, compared with the control group, the prepared PSFs-SAC composite films did not allow the total viable count (TVC), pH and total volatile base nitrogen (TVB-N) of the chilled pork to increase rapidly. Further, they were able to inhibit lipid oxidation more effectively (P < 0.05). For these reasons, the use of the PSFs-SAC composite films prolonged shelf life of chilled pork from 6 days to the 12 days. Therefore, PSFs-SAC composite films are expected to be used as bioactive substances in food preservation.

Effects of Flammulina velutipes polysaccharide with ice recrystallization inhibition activity on the quality of beef patties during freeze-thaw cycles: An emphasis on water status and distribution

The antifreeze activity of Flammulina velutipes polysaccharide (FVP) autoclave-extracted with dilute alkaline and effects of FVP on moisture status, size of ice crystals, physical and chemical characteristics of beef patties during repeated freeze-thaw (F-T) cycles were investigated. Results showed that FVP exhibited ice recrystallization inhibition activity and was able to alter the onset freezing/melting temperature of beef patties. 0.01% FVP significantly alleviated (P < 0.05) the decrement in water holding capacity by inhibiting water migration, restraining the mobility of water, and reducing the size of ice crystals of beef patties during the repeated F-T cycles. In addition, FVP could effectively inhibited oxidation reaction and protein aggregation of beef patties with significant decreases in TBARS value, protein turbidity, contents of total sulfhydryl and carbonyl of myofibrillar protein, and an increase in protein solubility during the repeated cycles. These results suggest FVP could be developed to be a promising cryoprotectant in frozen patties.

Phenolic acid-chitosan derivatives: An effective strategy to cope with food preservation problems

Chitosan, a cost-effective and eco-friendly natural polymeric material, possesses excellent film-forming properties. However, it has low solubility and biological activity, which hinders its widespread applications. To overcome these limitations, researchers have developed phenolic acid-chitosan derivatives that greatly enhance the mechanical, antibacterial and antioxidant properties of chitosan, expanding its potential application, particularly in food preservation. This review aims to provide an in-depth understanding of the structure and biological activity of chitosan and phenolic acid, as well as various synthetic techniques employed in their modification. Phenolic acid-chitosan derivatives exhibit improved physicochemical properties, such as enhanced water solubility, thermal stability, rheological properties, and crystallinity, through grafting techniques. Moreover, these derivatives demonstrate significantly enhanced antibacterial and antioxidant activities. Through graft modification, phenolic acid-chitosan derivatives offer promising applications in food preservation for diverse food products, including fruits, vegetables, meat, and aquatic products. Their ability to improve the preservation and quality of these food items makes them an appealing option for the food industry. This review intends to provide a deeper understanding of phenolic acid-chitosan derivatives by delving into their synthetic technology, characterization, and application in the realm of food preservation.

The effect of essential oil of Zataria multiflora incorporated chitosan (free form and Pickering emulsion) on microbial, chemical and sensory characteristics in salmon (Salmo trutta)

The objective of current research was to prepare a new biodegradable coating containing chitosan (Ch) and zataria multiflora essential oil (ZMEO) (free and Pickering emulsion (PEO) forms), in order to enhance the Salmo trutta shelf life. Our results showed, the mean of films thickness, mechanical properties (elastic modulus (EM) and tensile strength (TS) analysis) and WVP in different treatments were ranged from 0.103 ± 0.003 (for Ch) to 0.109 ± 0.003 (for Ch-PEO (2.5 %)) µm for thickness, from 3.2 ± 1.6 (for Ch) to 8.15 ± 2.3 (for Ch-EO) MPa for EM, from 1.3 ± 0.5 (for Ch-EO) to 1.6 ± 0.06 (for Ch) Mpa for TS and from 0.1 ± 0.02 (for Ch) to 0.8 ± 0.05 (for Ch-EO) (×10 - 11(g m/m2 s Pa) for WVP. In current research, the lowest and highest total viable counts (TVC) was related to Ch-PEO (1.7 log CFU/g) and control treatments (4.65 log CFU/g). The lowest and highest of pH was related to the Ch-PEO (6.45) and the control (7.1), the lowest and highest of PV (peroxide value) was related to Ch-PEO (0.34 meq/kg) and control treatment (1.37 meq/kg), the lowest and highest of TBARS (thiobarbituric acid reactive substances) was related to Ch-PEO (0.37 mg/kg) and control treatment (2.23 mg/kg) and also the lowest and highest of TVB-N (total volatile base nitrogen) was related to Ch-PEO (17.7 mg) and control (59 mg). Also, Ch-PEO showed the best sensory properties after sixteen days. Among all the treatments in all the tests, the best maintenance property was related to the Ch-PEO, therefore, chitosan coatings containing ZM Pickering emulsion should be considered as a potential active coating in the fish industry.

Photothermal synergistic nitric oxide controlled release injectable self-healing adhesive hydrogel for biofilm eradication and wound healing

The development of injectable self-healing adhesive hydrogel dressings with excellent bactericidal activity and wound healing ability is urgently in demand for combating biofilm infections. Herein, a multifunctional hydrogel (QP/QT-MB) with near-infrared (NIR) light-activated mild photothermal/gaseous antimicrobial activity was developed based on the dynamic reversible borate bonds and hydrogen bonds crosslinking between quaternization chitosan (QCS) derivatives alternatively containing phenylboronic acid and catechol-like moieties in conjunction with the in situ encapsulation of BNN6-loaded mesoporous polydopamine (MPDA@BNN6 NPs). Given the dynamic reversible cross-linking feature, the versatile hybrid hydrogel exhibited injectability, flexibility, and rapid self-healing ability. The numerous phenylboronic acid and catechol-like moieties on the QCS backbone confer the hydrogel with specific bacterial affinity, desirable tissue adhesion, and antioxidant stress ability that enhance bactericidal activity and facilitate the regeneration of infection wounds. Under NIR irradiation, the QP/QT-MB hydrogels exhibited a desirable mild photothermal effect and NIR-activity controllable NO delivery, combined with the endogenous contact antimicrobial activity of hydrogel, contributing jointly to induce dispersal of biofilms and disruption of the bacterial plasma membranes, ultimately leading to bacteria inactivation and biofilm elimination. In vivo experiments demonstrated that the fabricated QP/QT-MB hydrogel platform was capable of inducing efficient eradication of the S. aureus biofilm in a severely infected wound model and accelerating infected wound repair by promoting collagen deposition, angiogenesis, and suppressing inflammatory responses. Additionally, the QP/QT-MB hydrogel demonstrated excellent biocompatibility in vitro and in vivo. Collectively, the hydrogel (QP/QT-MB) reveals great potential application prospects as a promising alternative in the field of biofilm-associated infection treatment.

Effect of chitosan-gelatine edible coating containing nano-encapsulated clove ethanol extract on cold storage of chilled pork

Meat safety and quality are the main concerns of consumers in the present food market. Chitosan-gelatin edible coatings containing nano-encapsulated clove ethanol extracts (CNPs), designated as CHI-GEL-CNPs, on the quality preservation of chilled pork were studied. Results showed that the mean particle diameters of CNPs were 346.15 ± 37.30 nm. Nano-modification improved the antibacterial activity of free clove ethanol extract. The increasing rate order of TVB-N and TBARS was CHI-GEL-CNPs < CHI-GEL-Clove < CHI-GEL < CHI < CON group. The CHI-GEL-CNPs coating inhibited the elevation of pH and total viable count (TVC) of chilled pork. The TVB-N and TVC values demonstrated that the CHI-GEL-CNPs coating effectively extended the shelf life of chilled pork up to 13 days. In addition, the sensory properties of CHI-GEL-CNPs chilled pork loins were superior to that of control samples. Therefore, the developed CHI-GEL-CNPs coatings have great promise as a nanocomposite for meat preservation.

Proteomic analysis of Staphylococcus aureus exposed to bacteriocin XJS01 and its bio-preservative effect on raw pork loins

Antibacterial mechanism of bacteriocins against foodborne S. aureus is still to be explored, particularly in proteomics, and a deep and comprehensive study on application of bacteriocins for preservation of raw pork is required. Here, proteomic mechanism of Lactobacillus salivarius bacteriocin XJS01 against foodborne S. aureus 2612:1606BL1486 (S. aureus_26) and its preservation effect on raw pork loins stored at 4 °C for 12 days was investigated. The results showed that 301 differentially abundant proteins (DAPs) were identified between XJS01-treated and -free groups (control group) using Tandem mass tag (TMT) quantitative proteomics technology, which were primarily involved in amino acids and carbohydrate metabolism, cytolysis, defense response, cell apoptosis, cell killing, adhesion, and oxygen utilization of S. aureus_26. Bacterial secretion system (SRP) and cationic antimicrobial peptide resistance may be key pathways to maintain protein secretion and counteract the deleterious effects on S. aureus_26 caused by XJS01. In addition, XJS01 could significantly improve the preservation of raw pork loins by the evaluation results of sensory and antibacterial activity on the meat surface. Overall, this study showed that XJS01 induced a complex organism response in S. aureus, and it could be potential pork preservative.

Chitosan-grafted phenolic acids as an efficient biopolymer for food packaging films/coatings

Chitosan (CS), a bio-renewable natural material, has the potential to be utilized as a biopolymer for food packaging films (PFs)/coatings. However, its low solubility in dilute acid solutions and poor antioxidant and antimicrobial activities limit its application in PFs/coatings. To address these restrictions, chemical modification of CS has garnered increasing interest, with graft copolymerization being the most extensively used method. Phenolic acids (PAs) as natural small molecules are used as excellent candidates for CS grafting. This work focuses on the progress of CS grafted PA (CS-g-PA) based films, introducing the chemistry and methods of preparing CS-g-PA, particularly the effects of different PAs grafting on the properties of CS films. In addition, this work discusses the application of different CS-g-PA functionalized PFs/coatings for food preservation. It is concluded that the food preservation capability of CS-based films/coatings can be improved by modifying the properties of CS-based films through PA grafting.

Antibacterial and antioxidant properties of phenolic acid grafted chitosan and its application in food preservation: A review

Chitosan is a bio-renewable natural polymeric material. The antibacterial and antioxidant activity of chitosan can be enhanced by grafting with phenolic acids to further expand its application in food. Therefore, this paper focuses on reviewing the structure, antimicrobial and antioxidant activities and their mechanisms with phenolic acid-g-CS, evaluating its cytotoxicity, and describing its application in various food preservation. In general, different reaction mechanisms of phenolic acid-g-CS synthesis lead to different product structures. Compared to chitosan, phenolic acid-g-chitosan exhibited enhanced antibacterial and antioxidant activities. The toxicity assessment showed that phenolic acid-g-CS is not cytotoxic. Moreover, phenolic acid-g-CS has been applied to a variety of food products such as fruits, vegetables and meat with good results. Overall, this review provides a certain reference for subsequent researchers to design phenolic acid-g-CS more rationally and for the subsequent development of phenolic acid-g-CS in food preservation.

Insight into the relationship between metabolite dynamic changes and microorganisms of sea urchin (S. intermedius) gonads during storage

Sea urchin gonads have high nutritional value and degenerate rapidly during storage. Previous assessment of the freshness of sea urchin gonads was based on experience without valid biochemical indicators. Thus, the current study is to find biochemical indicators representing the freshness of sea urchin gonads. Results showed that the dominant genera of sea urchin gonads were changed from Psychromonas, Ralstonia, and Roseimarinus to Aliivibrio, Psychrilyobacter, and Photobacterium. The differential metabolites of sea urchin gonads were mainly produced through amino acids metabolism. Among them, GC-TOF-MS based differential metabolites had the greatest enrichment in the valine, leucine and isoleucine biosynthesis pathway, while LC-MS based differential metabolites had the greatest enrichment in the alanine, aspartate and glutamate metabolism pathway. The growth of dominant genus (Aliivibrio) had a great influence on the production of differential metabolites. These results will provide valuable information for accurately judging the freshness and shelf life of sea urchin gonads.

Chitosan Coating Functionalized with Flaxseed Oil and Green Tea Extract as a Bio-Based Solution for Beef Preservation

Ecological and safe packaging solutions arise as pivotal points in the development of an integrated system for sustainable meat production. The aim of this study was to assess the effect of a combined chitosan (Ch) + green tea extract (GTE) + essential oil (thyme oil, TO; flaxseed oil, FO; or oregano oil, OO) coating on the safety and quality of vacuum-packaged beef during storage at 4 °C. An optimized bio-based coating formulation was selected (2% Ch + 2% GTE + 0.1% FO) to be applied to three fresh beef cuts (shoulder, Sh; knuckle, Kn; Striploin, St) based on its pH (5.8 ± 0.1), contact angle (22.3 ± 0.4°) and rheological parameters (viscosity = 0.05 Pa.s at shear rate > 20 s^-1). Shelf-life analysis showed that the Ch-GTE-FO coating delayed lipid oxidation and reduced total viable counts (TVC) and Enterobacteriaceae growth compared with uncoated beef samples over five days. In addition, Ch-GTE-FO coating decreased total color changes of beef samples (e.g., ∆E* = 9.84 and 3.94, for non-coated and coated Kn samples, respectively) for up to five days. The original textural parameters (hardness, adhesiveness and springiness) of beef cuts were maintained during storage when Ch-GTE-FO coating was applied. Based on the physicochemical and microbial characterization results, the combination of the Ch-GTE-FO coating developed was effective in preserving the quality of fresh beef cuts during refrigerated storage along with vacuum packaging.

Effective Preservation of Chilled Pork Using Photodynamic Antibacterial Film Based on Curcumin-β-Cyclodextrin Complex

A biodegradable photodynamic antibacterial film (PS-CF) was prepared using the casting method, with κ-Carrageenan (κ-Car) as the film-forming substrate and curcumin-β-cyclodextrin (Cur-β-CD) complex as photosensitizer. Chilled pork samples were coated with PS-CF and stored at 4 °C to investigate the effects of PS-CF combined with LED light irradiation (425 nm, 45 min) (PS+L+) on pork preservation during 10 days of storage. The total viable count (TVC) of bacteria, total volatile basic nitrogen value (TVB-N) and the pH of pork treated with PS+L+ were all lower than the control, and the water-holding capacity (WHC) was higher. Ten days later, the TVB-N value was 12.35 ± 0.57 mg/100 g and the TVC value was 5.78 ± 0.17 log CFU/g, which was within the acceptable range. Sensory evaluation determined that the color, odor, and overall acceptability of pork treated with PS+L+ were significantly better than the control. These findings suggest that PS+L+ treatment effectively extended the shelf life of chilled pork from ~4-5 to 10 days. Correlation analysis showed that the sensory quality of the chilled pork significantly correlated with total bacterial counts, TVB-N and thiobarbituric acid reactive substances (TBARS) (p < 0.05), suggesting that these biomarkers could be used as standard indicators for evaluating the freshness of chilled pork. These findings demonstrate the effectiveness of Cur-β-CD photodynamic antibacterial film for the preservation of chilled pork and provide a theoretical basis for the application of the film for the preservation of fresh food in general.

Fabrication of robust silver plated conductive polyamide fibres based on tannic acid modification

A novel method for the preparation of silver plated conductive polyamide fibres (PA/Ag) based on tannic acid modification was reported in this work. The highly adhesive tannic acid was grafted onto the surface of sulphuric acid roughened polyamide fibres to sensitize the fibre. Then, the sensitized polyamide fibres were activated by low-concentration silver nitrate to form reactive centers. Chemical silver plating was finally carried out using silver ammonia solution with glucose. The surface morphology and chemical properties of the prepared polyamide fibres were analyzed and the surface resistance, fastness to washing, thermal decomposition properties, electrothermal properties, sensing properties and practical applications of the silver-plated polyamide fibres were also tested. The test results show that the prepared conductive fibres have excellent conductivity and stability, and have potential applications in flexible electronic devices and sensing fields.