Effect of chitosan coating combined with pomegranate peel extract on the quality of Pacific white shrimp during iced storage

Recent progress in biomedical applications of chitosan and its nanocomposites in aquaculture: A review

Chitosan nanoparticles (CSNPs) are the nanostructures of chitosan biopolymer which is derived from chitin polysaccharide, the main component of crustacean shells. Chitosan is a biocompatible, nontoxic and biodegradable polymer soluble in acidic solutions and easily excreted from kidneys. It is widely used in medical and pharmaceutical applications including artificial matrices for tissue engineering, drug transport, targeted drug delivery and protein or gene delivery. The antimicrobial activities of chitosan and CSNPS against different bacterial, fungal and viral pathogens made them valuable for several biological applications including food preservation purposes. In addition, they have immunomodulatory effects on fish and crustaceans providing direct positive impact on aquaculture and fish farming industry. Sustained release of some bioactive ingredients such as hormones, vitamins, nutrients and antioxidants has improved the biological activities of fish. Furthermore, CSNPs have recently been employed to diagnose fish diseases. In this review, we present the medical and biological applications of chitosan and CSNPs on aquatics to provide an update on recent advances and the potential for further advanced applications for aquaculture in the future.

Use of Cold Atmospheric Plasma To Preserve the Quality of White Shrimp (Litopenaeus vannamei)

HIGHLIGHTS

Discharge of dielectric barriers significantly reduced microbial populations. Treatments resulted in improvement in physical characteristics during storage. Nonthermal plasma provided a 43% (4-day) increase in sample lifetime.

Chitosan-based (Nano)materials for Novel Biomedical Applications

Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Multiple perspectives of the proposed antibacterial effect and mode of action of chitosan-based nanomaterials are reviewed. Chitosan is presented as an ideal biomaterial for antimicrobial wound dressings that can either be fabricated alone in its native form or upgraded and incorporated with antibiotics, metallic antimicrobial particles, natural compounds and extracts in order to increase the antimicrobial effect. Since chitosan and its derivatives can enhance drug permeability across the blood-brain barrier, they can be also used as effective brain drug delivery carriers. Some of the recent chitosan formulations for brain uptake of various drugs are presented. The use of chitosan and its derivatives in other biomedical applications is also briefly discussed.

Characterization of Bacterial Microbiota in Tilapia Fillets Under Different Storage Temperatures

This paper investigates the bacterial microbiota in tilapia fillets under cold (4 °C), iced (0 °C), and superchilled (-3 °C) storage conditions. At 4 °C, at least seven species/strains of Pseudomonas were detected in the fillets, five of which were dominant either at a certain stage or throughout the entire storage period. Shewanella was less dominant than Pseudomonas at 4 °C, while Serratia became dominant after 6 days storage at 4 °C. The microbiota in fillets stored at 0 and -3 °C were very similar and rarely changed during storage, yet differed greatly from the microbiota at 4 °C. Only two Pseudomonas species/strains grew at 0 and -3 °C, one of which was the most dominant. A Vibrionimonas sp. not found at 4 °C was found to be the second most dominant species at 0 and -3 °C. Shewanella and Psychrobacter were also present at 0 and -3 °C but were the minor genera. The most dominant strains at -3, 0, and 4 °C were separately isolated and subjected to full length 16S rDNA sequencing, which demonstrated that they were identical and were Pseudomonas fluorescens. The changes of the total bacterial count and TVBN value of the fillets inoculated with the isolated P. fluorescens were very similar to those of fillets with natural microbiota. This implies that P. fluorescens is the most important spoiler of tilapia fillets at -3, 0, or 4 °C. PRACTICAL APPLICATION: This research shows that fewer species of bacteria survive at 0 and -3 °C than those at 4 °C, while among these bacteria, the most important spoiler is P. fluorescens. This may provide some clues to extend the shelf life of tilapia fillets by taking some inhibitory measures targeted at P. fluorescens in the future.

Modification of Chitosan for the Generation of Functional Derivatives

Today, chitosan (CS) is probably considered as a biofunctional polysaccharide with the most notable growth and potential for applications in various fields. The progress in chitin chemistry and the need to replace additives and non-natural polymers with functional natural-based polymers have opened many new opportunities for CS and its derivatives. Thanks to the specific reactive groups of CS and easy chemical modifications, a wide range of physico-chemical and biological properties can be obtained from this ubiquitous polysaccharide that is composed of β-(1,4)-2-acetamido-2-deoxy-d-glucose repeating units. This review is presented to share insights into multiple native/modified CSs and chitooligosaccharides (COS) associated with their functional properties. An overview will be given on bioadhesive applications, antimicrobial activities, adsorption, and chelation in the wine industry, as well as developments in medical fields or biodegradability.

Localization of trypsin-like protease in postmortem tissue of white shrimp (Litopenaeus vannamei) and its effect in muscle softening

Fluorescein-isothiocyanate (FITC) labeled trypsin-like protease was prepared and injected into the hepatopancreas of white shrimp. Different segments of the injected shrimp were analyzed with a fluorescence microscope during storage. FITC-trypsin-like protease can be detected in the first segment of shrimp muscle at day 4, while it cannot be observed in the second segment until day 6. The results showed that trypsin-like protease can migrate from hepatopancreas to the tail portion. Texture profile analysis showed that soybean trypsin inhibitor retarded the softening of the shrimp muscle. The rheological results revealed that the content of myosin heavy chain (MHC) in shrimp muscle was decreased with the extended storage time. Proteomics analysis displayed that trypsin-like protease accelerated the metabolism of postmortem muscle. It can be concluded that trypsin-like protease migrated from the hepatopancreas to the muscle tissue, degraded myofibrillar protein, deteriorated the muscle texture, and eventually leaded to the softening of white shrimp.

Effect of ice water pretreatment on the quality of Pacific White Shrimps (Litopenaeus vannamei)

Pacific White Shrimps (Litopenaeus vannamei) are an aquaculture species with global importance. For the purpose of this paper, the quality shelling process of Pacific White Shrimps, freshly harvested from farms and stored in a mixture ice water up to 24 hr, was investigated. Both the differences and correlations between the indexes such as peeling time, shrimp yield, chromatic aberration, texture, K value, TBA value, and microstructure were compared and analyzed. The optimal shell peeling time of Pacific White Shrimps was determined by ice water treatment for 8 hr. The shell peeling time was 1.77 min, the elasticity of the shrimp was 0.51 mm, the hardness was 2,124.58 g, K value was 1.33%, and TBA value was 0.004 mg/100 g. Both the smell and color of the shelled shrimp were normal. This study aims to endorse the mechanical shelling of Pacific White Shrimps.

The Modification of In Situ SiOx Chitosan Coatings by ZnO/TiO2 NPs and Its Preservation Properties to Silver Carp Fish Balls

The composite chitosan coatings were prepared and characterized to evaluate their preservation properties for silver carp fish balls, and the microstructures and physicochemical properties of the coatings were improved by in situ nano silicon oxide (SiOx) and zinc oxide/titania (ZnO/TiO₂ ) nano-particles (NPs). In the chitosan coatings, when the chitosan combines with NPs by chemical bonds, the crystal lattice is slightly changed due to the modification of NPs. The chitosan coatings modified by NPs showed few cracks, among which sodium hexametaphosphate (SHMP) modified ZnO/TiO₂ /SiOx-chitosan (ZTS-CS) coating is proved to be the optimal one. The change of the freshness index and the texture of the fish balls are delayed by the coatings due to their gas permeability and antibacterial properties. The preservation properties of the chitosan coatings for Silver Carp fish balls are improved by in situ SiOx, and further improved by co-modification of ZnO/TiO₂ NPs. Furthermore, the surface modification of ZnO/TiO₂ NPs enhances the preservation properties of the chitosan coating. PRACTICAL APPLICATION: In our previous study, in situ SiOx was found to improve antibacterial and preservation properties of chitosan coating, leading to extending shelf time of Sciaenops ocellatus. In order to further improve properties of chitosan coatings, we added nontoxic edible nano materials to the in situ SiOx chitosan coatings. In situ SiOx modified by ZnO/TiO₂ NPs were synthesized, measured, and characterized in this study, and were applied for the preservation of silver carp fish balls. It could serve as a potential preservation material due to the increasing mechanical preservation properties. Through the results, the ZnO/TiO₂ /SiOx-chitosan (ZTS-CS) coatings have potential as application in the food industry to guarantee food quality and extend shelf life of products.

Challenges and opportunities related to the use of chitosan as a food preservative

Chitosan has attracted a growing attention as a food preservative due to its versatility, nontoxicity, biodegradability and biocompatibility. This review aims to provide a critical appraisal of the limitations and opportunities of the use of chitosan as a food preservative. The application of chitosan as a food preservative necessitates insights into mechanisms of chitosan-mediated cell death and injury, factors affecting chitosan activity and effects of chitosan on food safety and quality. Chitosan exerts antimicrobial activity by perturbing the negatively charged cell envelope of micro-organisms with its polycationic structure. Intrinsic characteristics, including molecular weight and degree of deacetylation (DD), and other ambient conditions, including pH, temperature and neighbouring components, affect chitosan activity. Because the antimicrobial activity of chitosan is mainly based on ionic interactions with negatively charged components of the bacterial cell envelope, the food matrix can strongly interfere with the antimicrobial activity of chitosan. Despite its limited antimicrobial efficacy, chitosan demonstrates both bactericidal and bacteriostatic effects in specific food products. Moreover, chitosan can also enhance the efficacy of commercial intervention technologies, such as heat and pressure treatment, and aid the preservation of food quality, including retardation of lipid oxidation, weight loss and deterioration in sensory attributes.

Changes in quality attributes of marine-trawling shrimp (Solenocera crassicornis) during storage under different deep-frozen temperatures

The objective of this study was to investigate the effect of variable deep-frozen temperatures storage (- 11, - 18, - 26 and - 37 °C) on quality characteristics of Solenocera crassicornis. Results for all frozen storage temperatures indicated that sensory quality, pH and colour change of frozen shrimp had high correlation with storage temperature, as a lower deep-frozen temperature was more effective in minimizing the sensory quality loss, pH and colour change. A kinetic analysis for total volatile basic nitrogen (TVB-N) and salt-soluble protein which was performed in this study, showed reaction rates inversely proportional to the deep-frozen temperature. Lipid oxidation in shrimp was quantified by determining the thiobarbituric acid reaction substances, and microbial growth were also monitored during the frozen storage. Among all groups, storage at - 37 °C was the most effective in controlling lipid oxidation and reducing aerobic bacterial count in shrimp. A comparison between different temperatures showed that qualities of shrimp stored at - 26 and - 37 °C were significantly better than those stored at - 11 and - 18 °C during frozen storage. In conclusion, the results are important to allow better management and optimization of the cold chain from manufacture to consumption.

Effect of chitosan-carvacrol coating on the quality of Pacific white shrimp during iced storage as affected by caprylic acid

This study aimed to investigate the effect of chitosan-carvacrol coating with or without caprylic acid (CAP) on the quality of Pacific white shrimp (Litopenaeus vannamei) during 10days of iced storage. The result showed that chitosan-carvacrol coating significantly inhibited the increase in total aerobic plate count (TPC), pH and total volatile basic nitrogen content (TVB-N) of shrimp in comparison with the control. Chitosan-carvacrol coating also delayed the melanosis formation and changes of ΔE values, and improved the texture and sensory properties of shrimp. Moreover, incorporation of CAP potentiated the efficacy of chitosan-carvacrol coating in retarding the increase of TPC and TVB-N. Incorporation of CAP into chitosan-carvacrol coating also enabled the texture characteristics of shrimp to be retained greater degrees. These results suggested that chitosan-carvacrol coating may be promising to be used as active packaging for extending the shelf life, and incorporation of CAP may enhance the efficacy of the coating.

Antimicrobial, Optical and Mechanical Properties of Chitosan-Starch Films with Natural Extracts

Natural extracts possess several kinds of antioxidants (anthocyanins, betalains, thymol, carvacrol, and resveratrol) that have also demonstrated antimicrobial properties. In order to study these properties, extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and resveratrol (from grapes) were obtained. Growth inhibition tests of mesophilic aerobes, coliforms, and fungi were conducted in films prepared from the extracts in accordance with Mexican Official Norms (NOM). Optical properties such as transparency and opacity, mechanical properties, and pH were also analyzed in these materials. The films with beetroot, cranberry, and blueberry extracts demonstrated the best antimicrobial activity against various bacteria and fungi in comparison with unmodified chitosan–starch film. This study shows that the addition of antioxidants improved the antimicrobial performance of these films. It was also found that antimicrobial properties are inherent to the films. These polymers combined with the extracts effectively inhibit or reduce microorganism growth from human and environmental contact; therefore, previous sterilization could be unnecessary in comparison with traditional plastics. The presence of extracts decreased transmittance percentages at 280 and 400 nm, as well as the transparency values, while increasing their opacity values, providing better UV–VIS light barrier properties. Despite diminished glass transition temperatures (Tg), the values obtained are still adequate for food packaging applications.

Chitosan films and coatings containing essential oils: The antioxidant and antimicrobial activity, and application in food systems

Chitosan edible films and coatings have shown great promise for their application in food preservation and also are promising systems to be used as essential oil (EO) carriers. This review reports the most recent and relevant studies concerning chitosan films and coatings containing EOs. The effect of EO incorporation on the antioxidant, antibacterial and antifungal activities of chitosan films and coatings in vitro and in vivo, as well as their applications in food systems have been discussed. In general, incorporation of EOs significantly increased the antioxidant, antibacterial and antifungal efficacy of chitosan films and coatings in vitro. EO-incorporated films and coatings also showed greater effectiveness against postharvest fungi and foodborne bacteria in food systems than pure films and coatings. The application of chitosan films and coatings containing EOs usually led to an extension of the shelf-life and reduction of lipid peroxidation of fish and meat products over pure chitosan films and coatings. In addition, chitosan coatings incorporated with EOs were more effective in maintaining fruit and vegetable quality, and controlling their postharvest decay during storage and shelf life than pure chitosan coatings.

Optimization of chitin yield from shrimp shell waste by Bacillus subtilis and impact of gamma irradiation on production of low molecular weight chitosan

Chitin and chitosan have been produced from the exoskeletons of crustacean shells such as shrimps. In this study, seventy bacterial isolates, isolated from soil, were tested for proteolytic enzymes production. The most efficient one, identified as Bacillus subtilis, was employed to extract chitin from shrimp shell waste (SSW). Following one-variable-at-a-time approach, the relevant factors affecting deproteinization (DP) and demineralization (DM) were sucrose concentration (10%, w/v), SSW concentration (5%, w/v), inoculum size (15%, v/v), and fermentation time (6days). These factors were optimized subsequently using Box-Behnken design and response surface methodology. Maximum DP (97.65%) and DM (82.94%) were predicted at sucrose concentration (5%), SSW concentration (12.5%), inoculum size (10%, containing 35×10(8) CFU/mL), and fermentation time (7days). The predicted optimum values were verified by additional experiment. The values of DP (96.0%) and DM (82.1%) obtained experimentally correlated to the predicted values which justify the authenticity of optimum points. Overall 1.3-fold increase in DP% and DM% was obtained compared with 75.27% and 63.50%, respectively, before optimization. Gamma-irradiation (35kGy) reduced deacetylation time of irradiated chitin by 4.5-fold compared with non-irradiated chitin. The molecular weight of chitosan was decreased from 1.9×10(6) (non-irradiated) to 3.7×10(4)g/mol (at 35kGy).

Effects of chitosan combined with nisin treatment on storage quality of large yellow croaker (Pseudosciaena crocea)

Effects of chitosan combined with different concentrations of nisin on quality enhancement of large yellow croaker (Pseudosciaena crocea) stored at 4 °C were evaluated for 8 days. Changes in sensory score and volatile spoilage products, total viable counts (TVC), and physiochemical indexes including weight loss, colour, pH, total volatile basic nitrogen (TVB-N), and K-value were examined. Results demonstrated that nisin-treated samples presented better quality preservation effects than chitosan alone. 1% chitosan combined with 0.6% nisin presented optimal quality enhancement effects, such as moisture loss control, volatile spoilage inhibition, TVB-N reduction, TVC growth control, and colour and sensory acceptability maintenance. Therefore, chitosan combined with nisin is promising in large yellow croaker shelf life extension.

Evaluation of different factors affecting antimicrobial properties of chitosan

Chitosan as one of the natural biopolymers with antimicrobial activities could be a good choice to be applied in many areas including pharmaceuticals, foods, cosmetics, chemicals, agricultural crops, etc. There have been many studies in the literature which show this superb polymer is dependent on many factors to display its antimicrobial properties including the environmental conditions such as pH, type of microorganism, and neighbouring components; and its structural conditions such as molecular weight, degree of deacetylation, derivative form, its concentration, and original source. In this review, after a brief explanation of antimicrobial activity of chitosan and its importance, we will discuss the factors affecting the antimicrobial properties of this biopolymer based on recent studies.