Total Volatile Basic Nitrogen Research Articles

Effect of PLA-Nanochitosan Films on the Shelf-Life Extension of Fresh Rainbow Trout Fillets

Fish-packaging technology is essential in maintaining the quality and shelf life of fish as a valuable and perishable food. This research was performed to evaluate the influence of polylactic acid-nanochitosan (PLA-NC) films containing Bunium persicum essential oil (BPEO) (0, 0.3, 0.6, and 0.9%) on microbial, chemical, and organoleptic characteristics of rainbow trout fillets during storage under refrigeration for 13 days. On the last day of the storage period, in the rainbow trout fillets wrapped with PLA-NC films containing BPEO, the microbial population declined by at least 1 log CFU/g in comparison with control samples. The initial value of the total volatile base nitrogen (TVB-N) of fillets was 10.28 mg/100 g and it reached 31.75 mg/100 g in the control group on day 4, while in rainbow trout fillets wrapped with PLA-NC films and complemented with BPEO, TVB-N contents were below 25 mg/100 g, until the 10th day of storage. Regarding the results of the current study, the peroxide value (PV) on day 0 was 1.7 meq/kg and reached 13.66 meq/kg in the control samples on the 13th day, while this parameter was lower than 10 meq/kg in samples wrapped with PLA-NC films complemented with BPEO on the final day of the study. The findings of this study illustrated that wrapping rainbow trout fillets in PLA-nanochitosan films complemented with BPEO prolonged the shelf life of rainbow trout fillets without any undesirable organoleptic attributes during storage under refrigeration for 10 days. The topography and surface composition of the prepared films was further confirmed using scanning electron microscope (SEM) and field scanning electron microscope (FESEM) analyses.

Chitosan-gelatin composite hydrogel antibacterial film for food packaging

Antibacterial hydrogel film can serve as food packaging materials to prevent bacteria growth and spread, thereby extending shelf life and improve food safety. In this study, an efficient antibacterial hydrogel film (CLG) was prepared with chitosan, lysine, and gelatin. The light transmission of the CLG hydrogel film was over 80 % in the visible region, facilitating the observation of chicken breast storage conditions. Additionally, the swelling ratios of the hydrogel films decreased with increasing gelatin concentration, from 145.7 g/g (CLG1) to 92.6 g/g (CLG2) and 81.5 g/g (CLG3). This reduction was attributed to the denser network structure formed by the interaction between gelatin and the CL polymer. The Scanning Electron Microscopy (SEM) showed that the water-absorbed CLG hydrogel had a unique sponge shape. Moreover, the CLG hydrogel film exhibits high antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In a practical storage experiment, the CLG hydrogel film extended the shelf life of chicken breast by up to 4 days compared to untreated samples, while effectively reducing total volatile basic nitrogen (TVB-N) levels. This hydrogel film is expected to become a promising food packaging material.

Preparation of Physalis alkekengi L. calyx total flavonoids-chitosan composite film and its effect on preservation of chilled beef.

In the present study, Physalis alkekengi L. calyx total flavonoids (PCTF) were extracted using the ultrasound-assisted ethanol method and separated and purified using macroporous resin AB-8. Physalis alkekengi L. calyx total flavonoid-chitosan (PCTF-CS) composite films containing 0.05 %, 0.10 % and 0.15 % PCTF were prepared using the purified PCTF laminated with chitosan (CS) and compared with single CS films, respectively, to investigate their mechanical properties, barrier properties, optical properties, microstructure, crystallography, thermal stability, water contact angle, particle size and zeta potential, antioxidant property, antimicrobial property, and preservation effect on chilled beef. The PCTF-CS films with PCTF additions had darker colors and higher mechanical and barrier properties than the CS films. In addition, the addition of PCTF improved the antioxidant and antimicrobial properties of the CS films. It enhances the freshness retention of fresh beef, and effectively inhibits the rise of weight loss, pH, total bacteria, total volatile basic nitrogen, and thiobarbituric acid reactive substances in beef, prolonging the shelf life of beef. These results indicate that the addition of PCTF can provide CS films with superior functional properties and bioactivities and that PCTF-CS composite films are a potential and promising packaging material for food preservation.

Differences in bacterial community structure and volatile flavor substance of industrial-scale tiger skin chicken feet stored at air packaging and vacuum packaging

The aim of this study was to investigate the differences of quality indexes, bacterial community and volatile organic compounds (VOCs) of industrial-scale tiger skin chicken feet (TSCF) under air packaging (AP) and vacuum packaging (VP). The results showed that the pH, total volatile basic nitrogen, total number of bacterial colony, and sensory scores in VP group changed less than those in AP group during the storage period. Different packaging conditions also had significant effects on bacterial community at the genus levels. Weissella and Lactococcus was the dominant genus in AP group, while Lactiplantibacillus and Pediococcus also had the large proportions in addition to Weissella and Lactococcus in VP group, which also led to the differences in VOCs between the two groups. Several VOCs could be used as potential spoilage indicators, including 2-octanone, ethanol, ethyl acetate and acetic acid in AP-stored TSCF, and 2-octanone, ethanol, ethyl acetate, 2-butyl-1-octanol, (R)-2-butanol, (E)-3-hexenoic acid and 2-butanone in VP-stored TSCF. Correlation analysis showed that these predominance spoilage microorganisms were significantly correlated with these VOCs of TSCF during the storage period. This study can provide a theoretical basis for understanding of the spoilage process of TSCF.

Evaluating the efficacy of citrus fruit peel extract in preserving the quality of silver carp (Hypophthalmichthys molitrix) surimi during frozen storage

This research investigated the effects of mosambi peel extract (MPE) on the stability of proteins and textural characteristics of silver carp surimi during frozen storage at -20°C. The findings revealed that surimi fortified with 0.75% MPE displayed upgraded protein solubility (PS), water holding capacity (WHC), Ca2+-ATPase activity, and sulfhydryl (SH) content. It also exhibited reduced levels of total carbonyls and surface hydrophobicity, along with higher overall acceptability compared to surimi treated with synthetic cryoprotectants (control) throughout storage. Additionally, MPE slowed down the increase in total volatile basic nitrogen (TVBN) and protein degradation index (PI), as evidenced by SDS-PAGE showing higher intensities of myosin heavy chain (MHC) and actin over the storage period. Moreover, the incorporation of MPE effectively mitigated lipid oxidation as peroxide value (PV), and thiobarbituric acid (TBA) were lesser than control. Fourier-transform infrared spectroscopy (FTIR) peaks specified that the relative content of α-helix and β-sheet structures remained more stable in the MPE-treated group compared to the control, along with the improved gel and textural properties of surimi. Hence, this study suggests that 0.75% MPE could serve as a natural alternative to synthetic cryoprotectants, ensuring the oxidative stability of silver carp surimi during frozen storage while enriching it with beneficial bioactive compounds.

Active and Intelligent Packaging Technology for Hilsa (Tenualosa ilisha)

During long marketing chain, Hilsa rapidly lose quality even in chilled condition. When purchase, consumers often get confused to differentiate between stale and fresh Hilsa. Four different active packages; namely, G1 (commercial oxygen absorber + nisin), G2 (commercial oxygen absorber + chitosan), G3 (glucose oxidase + nisin), and G4 (glucose oxidase + chitosan) were manufactured and tested to overcome these troubles. In case of thiobarbituric acid reactive substances (TBARS) content, G3 had lowest TBARS value followed by G4, G1 and G2, while control samples had the highest TBARS value. In regard to protein retention, all active packagings showed higher protein retention than control. Bacterial load was highest (4.87 log CFU/g) in control samples while active packagings had 2.29-3.96 log CFU/g. In case of total volatile basic nitrogen (TVB-N) content, G3 had minimum TVB-N content followed by G4, G1 and G2, while control samples had the highest TVB-N content. Phenol red dyed paper strips, which were used as intelligent indicator, did not change bright orange colour in active packages while turned into yellow and pale yellow in control and unacceptable samples, respectively. Active packagings were able to keep quality of Hilsa good for at least 28 days. Described active packagings technologies should be applied to enhance shelf-life of fishery products.

The Impact of an Edible Composite Coating Formulated with Farsi Gum and Iranian Black Cumin Essential Oil Emulsion or Nanoemulsion, Alongside Low-Dose Gamma Irradiation, on the Quality of Chilled Turkey Breast

Background: Hurdle technology is an effective method for preserving muscle food products and extending their shelf life. Objectives: This study evaluated the combined effect of Farsi gum (FG) coating impregnated with black cumin essential oil (BCEO) emulsion or black cumin nanoemulsion (BCNE) and low-dose gamma irradiation (GIR) at 2 kGy on the quality of turkey breast over 21 days of chilled storage. Methods: Turkey breast samples were divided into eight groups: Control, FG, GIR, FG + GIR, FG + BCEO, FG + BCNE, FG + BCEO + GIR, and FG + BCNE + GIR. The samples were assessed for microbial, physicochemical, and sensory attributes throughout 21 days of chilled storage. Results: The growth of mesophilic and psychrotrophic bacteria, Enterobacteriaceae, and lactic acid bacteria (LAB) was inhibited in all treated groups compared to the control and FG groups during the storage period. The treatments also curbed the increase in pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and protein carbonyls in the turkey breast. The most effective treatment for controlling microbial growth, minimizing physicochemical changes, and extending the storage life of turkey breast was the combination of FG + BCNE + GIR. Conclusions: The combination of active FG coating containing BCNE and low-dose GIR offers effective long-term preservation of turkey breast during chilled storage.

PH-sensitive intelligent packaging films from Kodo millet (Paspalum scrobiculatum) starch and gum tragacanth incorporated with beetroot peel extract for monitoring shrimp freshness

This study aims to develop intelligent pH-sensitive food packaging films based on kodo millet starch (KMS), gum tragacanth (GT), and zinc oxide nanoparticles (ZNP) incorporated with betalain-rich beetroot (Beta vulgaris L.) peel extract (BPE). The physical, mechanical, optical, microstructural, thermal, barrier, and functional properties of films with different BPE concentrations (50, 100, and 200 % of dry matter weight) were studied. The results proved betalain to be the major component in the BPE, which showed significant color change under alkaline conditions. Field emission scanning electron microscopy demonstrated good compatibility among the film constituents. Fourier transform infrared spectroscopy suggested hydrogen bonding interactions between the betalain-BPE and KMS/GT/ZNP-based film matrix. Incorporating the extract at different concentrations enhanced the ultraviolet-visible light barrier, antioxidant properties, and antimicrobial properties. The betalain-rich films showed color variation from pink in an acidic medium to yellow in an alkaline medium. The film with a 200 % concentration of BPE represented the highest color change when exposed to ammonia compared to other films. During the freshness indicator study of shrimp, the total volatile basic nitrogen concentration increased. The film with a 200 % concentration of betalain extract showed visible color changes from pink to pale yellow. Overall, our results suggest that the film containing a 200 % extract concentration can be used as an active pH-responsive packaging in the food industry.

Amine-responsive PVA-based fluorescent indicator films incorporating β-Glucan/FITC for visual detection of chilled meat freshness

Amine-responsive fluorescent indicator films for meat freshness were constructed by incorporating β-glucan grafted with fluorescein isothiocyanate (FITC) in polyvinyl alcohol (PVA). The structural, thermal, and responsive properties of grafted copolymers (βGlu-FITC) were investigated. The results of 1H NMR spectra showed that βGlu-FITC exhibited proton signals between 6.5 and 6.7 ppm, suggesting the successful grafting of FITC onto β-glucan. The fluorescence quantum yield of βGlu-FITC was 18.72%, which was higher than that of β-glucan of 12.94% at the optimum excitation wavelength of ultraviolet light of 365 nm. With the incorporation of PVA as a film-forming matrix, βGlu-FITC/PVA films showed high yellow-green fluorescent responsiveness under volatile ammonia and pH solution. When the film was used for meat freshness, the 0.06βGlu-FITC/PVA film provided a noticeable fluorescent indication of pork freshness that corresponded to increases in total volatile basic nitrogen, total colony counts, and drip loss, suggesting its potential for meat packaging and as a freshness indicator.

Highly sensitive zinc oxide nanoparticle composite film with deep learning-assisted mobile technology for enhanced food freshness monitoring

Smart packaging has been introduced to change the way that food freshness is managed. In this study, a new pH-sensitive film based on chitosan (CS), methylcellulose (MC), zinc oxide nanoparticles (ZnO-NPs), and black wolfberry (BW) anthocyanins was developed and characterized. The composite film showed high sensitivity to total volatile basic nitrogen (TVB-N), with clear and distinguishable color changes, improving freshness monitoring. The film demonstrated ultraviolet (UV) absorbance with an optimum concentration of ZnO-NPs at 4%, enhancing UV protection. The Visual Encoder Transformer (VET) model, trained on 4000 high-resolution images, predicted seafood freshness with an accuracy of 98.44%, outperforming other models. Additionally, the moisture content of the composite films decreased significantly from 18.64% to 7.35%, and the water contact angle increased to 92.89° with the incorporation of ZnO-NPs. The developed system, integrated with an Intelligent Color Recognition (ICR) mobile application, provides a real-time, non-invasive solution for monitoring food freshness, offering both high accuracy and practical usability in seafood packaging.

Integrating transfer learning and spectroscopy for enhanced pork spoilage assessment using correlation analysis

Accurate Total Viable Count (TVC) detection is vital for food quality monitoring. In this study, we investigated the feasibility of using visible near-infrared (VNIR) spectroscopy (400–1000 nm) combined with transfer learning (TL) to track the chemical spoilage of pork. The base models developed using the full band for pork TVC, total volatile basic nitrogen, pH, and color showed predictability; the correlation coefficient of prediction set (RP) for all models ranged from 0.821 to 0.916; and the root mean square error of prediction set (RMSEP) of the TVC model was 0.617 (lg CFU/g). A correlation analysis of the different indexes of pork was carried out to optimize the TVC calibration model. Different TL methods for TVC optimization were designed. The results showed that multiple correlation chain stacking-partial least squares performed best with RP, RMSEP, and the relative percent deviation of 0.947, 0.425 lg CFU/g, and 2.355, respectively, the RMSEP of TVC was reduced by 31.12 % as compared to the base model. This study demonstrated the possibility of combining the VNIR spectroscopy system with TL to monitor the degree of meat's chemical spoilage.

Effects of Red Vinasse on Physicochemical Qualities of Blue Round Scad (Decapterus maruadsi) During Storage, and Shelf Life Prediction.

A fish processed with red vinasse is a type of Fujian cuisine with regional characteristics. In order to monitor the effect of red vinasse on storage quality and shelf life of blue round scad (Decapterus maruadsi) during storage, the changes in fat content, thiobarbituric acid reactive substances (TBARS), composition of polyunsaturated fatty acids (PUFAs), pH value, texture, and sensory quality were studied at different storage temperatures (4 °C, 25 °C, and 37 °C). By analyzing the correlation between changes in sensory qualities and physical and chemical indexes, a first-order kinetic model and the Arrhenius equation were used to build a shelf-life prediction model for blue round scad during storage. The results showed that processing with red vinasse can significantly reduce the malondialdehyde (MDA) production and the decrease in PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (p < 0.05) during storage. Based on partial least squares regression (PLSR), the storage temperature and time have a significant impact on the PUFA composition in blue round scad, which changed less when the samples were stored at 4 °C and 25 °C, and they had better nutritional composition of fatty acids at lower temperatures. Among the PUFAs, DHA (C22:6n-3) and EPA (C20:5n-3) had higher relative contents and significantly decreased during storage (p < 0.05). Additionally, the processing with red vinasse can slow down the increase in total volatile basic nitrogen (TVB-N) value and pH of blue round scad, maintain the appropriate hardness, elasticity, cohesion and chewability, and improve the overall sensory quality of the fish. In addition, according to the results of model prediction based on TBARS value, the storage shelf life of blue round scad with red vinasse added was 55 d, 2.7 d and 28 h at 4 °C, 25 °C and 37 °C, respectively. The accuracy of the forecast model was high, and the relative errors of the measured values and predicted values were less than 10%. Thus, it not only provided a theoretical basis for the processing and application of red vinasse to Chinese traditional food, but also provided innovative ideas for the safe storage and high-value utilization of blue round scad.

Beet Root Peel Extract as a Natural Cost‐Effective pH Indicator and Food Preservative in Edible Film: Shelf Life Improvement of Cold‐Stored Trout Fillet

ABSTRACTIn this study, chitosan (C)‐polyvinyl alcohol (P) edible film containing bio‐fabricated nanosilver particles (nAg) (as antimicrobial agent) and beetroot peel extract (BRPE) (as antioxidant agent and pH indicator) was used as spoilage indicator in cold‐stored rainbow trout fillets. DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radical scavenging activity (43.02%), reducing power (2.87), and total phenolic content (360.50 mg GAE/g) of ethanolic BRPE were higher than aqueous extract. Silver nanoparticles were biosynthesized using silver nitrate reduction by chitosan, confirmed by UV–Visible spectroscopy, optical and scanning electron microscope images, and X‐ray diffraction analysis. The highest tensile strength (4.20 MPa) and elongation at break (118%) belonged to the CP‐BRPE film, and the lowest water vapor permeability (2.45 10−5 g/s/m/P) was related to the CP‐nAg film. Also, the lowest total viable count (6.17 log CFU/g), psychrotrophic bacteria (6.27 log CFU/g), Enterobacteriaceae (4.9 log CFU/g), pH (5.66), total volatile basic‐nitrogen (TVB‐N) (22.1 mg/100 g of fish), and thiobarbituric acid reactive substances (TBARS) (0.705 mg MDA/kg of fish) values of the packaged trout fillets were significantly (p ≤ 0.05) observed in CP‐BRPE‐gnAg treatment among the other treatments at the end of the storage period, and CP‐gnAg, CP‐BRPE, and CP treatments were in the next ranks, respectively. Colorimetric analysis of the used films showed that the films containing BRPE depicted color spectra of red to yellow at the same time as the spoilage symptoms initiated in the packaged fillets. It is concluded that BRPE not only increased the preservative effects of chitosan‐polyvinyl alcohol film containing green silver nanoparticles but also can be considered as a natural cost‐effective spoilage indicator of the rainbow trout fillets during cold storage time.

Application of high-hydrostatic pressure to extend shelf life of miso-marinated escolar loins during cold storage

The changes in the microbiological and chemical qualities of escolar meat following high-pressure processing (HPP) (300–600 MPa, 5 min) along with miso marinade for 15 days with refrigeration were evaluated. Miso marinade and HPP treatment of escolar meat had synergistic inactivating effects on microorganisms that were more pronounced at higher pressures. In addition, when stored at 4 °C, the combination of miso marinade and HPP treatment significantly delayed microbial growth and total volatile basic nitrogen (TVBN) production and inhibited pH changes. Using TVBN <25 mg/100 g as the criterion for freshness, miso marinade and HPP treatment (300–600 MPa) extended the refrigerated storage period from 3 days without treatment and 6 days with miso marinade alone to 15 days. In addition, high-throughput sequencing analysis showed that the combination of miso marinade and HPP treatment significantly altered the microbiome of the fish during refrigeration, thereby slowing the spoilage process. This study demonstrated that miso marinade along with HPP treatment can improve color and texture, inhibit microbial growth, delay quality deterioration, and prolong the shelf life of fish meat. Therefore, high pressure together with miso marinade is an effective hurdle technique for improving the quality and freshness of aquatic products.

Characterization and coating application of composite gelatin packaging containing eucalyptus leaf essential oil liposome and phage endolysin for preservation of pacific white shrimp (Penaeus vannamei)

Shrimp are highly susceptible to spoilage during cold storage because of microbial growth and lipid oxidation. This study presents the development and characterization of a novel composite gelatin packaging that incorporates eucalyptus leaf essential oil liposome (EEOL) and phage endolysin (rLys). It also assesses the effectiveness of coating application for shrimp preservation to provide an effective strategy. The addition of EEOL and rLys to gelatin packaging not only enhanced film flexibility (13.16%–13.42%) and reduced oxygen permeability (0.95-0.96 × 10−7 g m−1·s−1), but also endowed the films with antioxidant (DPPH radical scavenging rate of 67.14%–67.28%) and antimicrobial properties (complete inhibition at low titers and a reduction of 3.00–4.05 log10 CFU/mL at high titers). In the shrimp coating preservation experiment, the quality of untreated shrimp started to deteriorate on the 3rd day. In contrast, the pH values, total volatile base nitrogen (TVB-N) content, and total viable count (TVC) of shrimp with the composite coatings on the 7th day were 7.28, 154.02–175.08 mg/kg, and 4.34–5.34 log10 CFU/g, respectively, remaining within the limits of the Chinese national standard. Moreover, the release of EEOL from the composite coatings led to thiobarbituric acid values (TBA) of 0.19–0.21 mg malondialdehyde (MDA)/kg on the 5th and 7th day, respectively. Additionally, rLys in the coating significantly decreased the numbers of Escherichia coli O157:H7 and Salmonella enteritidis in the shrimp body by 1.04–1.06 log10 CFU/g and 1.13–1.14 log10 CFU/g, respectively. These results suggest that the synergistic effect of EEOL and rLys in composite gelatin coating, especially the Ge-EEOL-rLys60, can extend the preservation period of shrimp to 5 d or even longer, thereby providing the possibility of maintaining shrimp freshness and safety.

Influence of Coated Phycocyanin on Shelf Life of Infected Penaeus semisulcatus

ABSTRACTThe present study was undertaken to evaluate the antioxidant and antimicrobial activity of chitosan‐alginate‐coated phycocyanin (PC) extract from Spirulina sp. on Penaeus semisulcatus infected with Salmonella typhimurium stored at 4°C and 8°C for 21 days. Four groups of shrimp treatments—a control sample (without infection and PC), an infected sample without PC, a non‐infected sample + PC and an infected sample + PC—were used. The toxicity test revealed no toxicity of PC against Caenorhabditis elegans. The results of the pH, thiobarbituric acid, peroxide value (PV) and total volatile basic nitrogen showed that the lowest amounts of these factors were observed in the samples immersed in PC, whereas the highest values belonged to the samples infected with Salmonella. On the basis of the total number of bacteria in food (log 10⁷ CFU/g), the shelf life of shrimps treated with PC increased by 14 and 4 days at 4°C and 8°C, respectively, compared to the control. The diphenyl‐2‐picrylhydrazyl (DPPH) and ABTS results of the antioxidant activity indicated that the highest values were observed in the infected sample + PC after 21 days at 4°C and 8°C (82.65 ± 0.36 and 89.50 ± 0.43), respectively. The results of the colour assessment showed that the highest and lowest values belonged to the control sample (without infection and PC) and the non‐infected sample with PC, respectively. The results of sensory analysis showed that the samples enriched with PC had a higher overall acceptability than samples without PC. In conclusion, PC increased the shelf life of shrimp infected with Salmonella sp.

Halochromic aerogels with Ca2⁺-induced tailored porosity based on alginate/gellan integrated with Echium amoenum anthocyanins: Characterization and application for freshness monitoring of rainbow trout fillet

This study aimed to fabricate a food freshness halochromic aerogel based on alginate, gellan, and Echium amoenum anthocyanins (EA). The porosity and morphological properties of the aerogels (AG2, AG6, and AG10) were regulated by varying the concentration of CaCl2 (2, 6, 10 %). FE-SEM analysis revealed that increasing the CaCl2 content led to the formation of aerogels with enhanced overall porosity and larger pore sizes. The AG6 aerogel, characterized by a density of 23.44 ± 0.04 mg/cm³, a porosity of 91.66 ± 0.06%, and an average pore size of 306.93 ± 122.89 μm, was identified as the optimal support for the incorporation of the EA pigment. FT-IR analysis verified the formation of hydrogen bonds between the AG6 aerogel and EA molecules. Incorporating anthocyanin increased the crystallinity and thermal stability of the aerogel, as evidenced by XRD and DSC analyses. The AG6EA aerogel displayed a color shift from red to yellow over a pH range of 2–12. The AG6EA aerogel demonstrated high sensitivity to ammonia vapor and proper color stability and reversibility. The AG6EA aerogel color transitioned from purple to blue and then green through rainbow trout storage, correlating with changes in pH, total volatile basic nitrogen (TVB-N), and total viable microbial count (TVC and TPC) of the fish samples. This research extends a new insight to develop cutting-edge, susceptible, and accurate pH indicators capable of quality assessment of protein-based food products.

An Intelligent Indicator Film Based on Food Derived Materials for Real-Time Visual Monitoring of Salmon Freshness

ABSTRACT Determining the freshness of aquatic products during food processing, transportation, and preservation is critical for ensuring food safety and quality. In this study, we developed intelligent indicator films sensitive to nitrogen compounds using sodium alginate, glycerol, and natural pigments. These films exhibited excellent indicating performance in monitoring the freshness of salmon, including total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBARS), and pH levels. Additionally, the intelligent indicator films exhibit both thermal stability and good biocompatibility. This finding paves the way for developing safe and effective food freshness indicators with potential uses in transportation, packaging, and related industries.

Antimicrobial and biodegradable hydrogel based on nanocellulose/alginate incorporated with silver nanoparticles as active packaging for poultry products

In this research, active packaging which was made of all-natural component hydrogels from nanocellulose composited with silver nanoparticles at various concentrations (AgH) was studied. The concentration of silver nanoparticles ranged from 0.0078 to 0.0624 phr. AgH was characterized in terms of basic properties, functional properties, and packaging applications. Biocompatibility testing with the Caco-2 cell line showed that higher concentrations of silver (higher than 0.0312 phr) provided a lower cell viability rate (lower than 70% cell viability). Here, 0.0156 phr of silver nanoparticle concentration was the maximum loading that is safe for the target cell (82% cell viability) and was thus selected for use as active packaging. The antimicrobial activity showed that AgH at all concentrations inhibited both Gram bacteria up to 99.99%. Total volatile basic nitrogen compound testing showed that chicken meat preserved by AgH had the lowest values, indicating that AgH can prolong the shelf life in freshness level 1 (15% TVB-N) for 6.2 days compared to 3.9 and 4.1 days of blank and neat cellulose hydrogel. In addition, all AgH were gradually degraded over time and eventually disappeared within 15–30 days in organic soil.

Impacts of chitosan/pullulan/carvacrol film on the quality and microbial diversity of refrigerated goat meat

In this study, our previously prepared chitosan/pullulan film (CS/PU) and chitosan/pullulan/carvacrol film (CS/PU/CAR) were applied to goat meat preservation, the dynamic changes in quality and microbial communities of goat meat during chilled storage (4 °C) were investigated, and the fresh-keeping effects of the two biodegradable antibacterial films on goat meat were comprehensively evaluated. The results showed that when the goat meat was wrapped with CS/PU or CS/PU/CAR films during chilled storage, the total plate count and total volatile basic nitrogen (TVB-N) could be inhibited significantly, but the CS/PU/CAR film has a better fresh-keeping effect. Furthermore, during the chilled storage of goat meat, CS/PU/CAR film also could inhibit the production of alcohol compounds and the growth of Pseudomonas spp., thereby slowing down the meat's deterioration and extending the goat meat's shelf life to about 13 days. This study can provide a reference for the application of active packaging film of fresh goat meat.