Synthesis and Evaluation of Gelatin-Chitosan Biofilms Incorporating Zinc Oxide Nanoparticles and 5-Fluorouracil for Cancer Treatment.

In this study, a novel multifunctional biofilm was fabricated using a straightforward casting process. The biofilm comprised gelatin, chitosan, 5-fluorouracil (5-FU)-conjugated zinc oxide nanoparticles, and polyvinyl alcohol plasticized with glycerol. The 5-FU-conjugated nanoparticles were synthesized via a single-step co-precipitation process, offering a unique approach. Characterization confirmed successful drug conjugation, revealing bar-shaped nanoparticles with sizes ranging from 90 to 100 nm. Drug release kinetics followed the Korsmeyer-Peppas model, indicating controlled release behavior. Maximum swelling ratio studies of the gelatin-chitosan film showed pH-dependent characteristics, highlighting its versatility. Comprehensive analysis using SEM, FT-IR, Raman, and EDX spectra confirmed the presence of gelatin, chitosan, and 5-FU/ZnO nanoparticles within the biofilms. These biofilms exhibited non-cytotoxicity to human fibroblasts and significant anticancer activity against skin cancer cells, demonstrating their potential for biomedical applications. This versatility positions the 5-FU/ZnO-loaded sheets as promising candidates for localized topical patches in skin and oral cancer treatment, underscoring their practicality and adaptability for therapeutic applications.

Carboxymethyl cellulose/gelatin film incorporated with eggplant peel waste-derived carbon dots for active fruit packaging applications.

Carbon dots (CDs) were derived using eggplant peel by a hydrothermal approach and incorporated into the carboxymethyl cellulose (CMC) and gelatin (Gel) blend to develop sustainable and functional packaging films for fruit preservation. The CD was uniformly dispersed within the CMC/Gel blend to form a dense and continuous film and fashioned a strong interaction with the polymer chain, increasing the tensile strength of the film by 5.0-16.0 %. Also, with the impregnation of CDs, the UV-blocking potential of the CMC/Gel film was greatly improved to the extent of blocking 94.3 % of UV-B and 72.5 % of UV-A, while the water vapor permeability slightly decreased (by 2.7-5.4 %), and the water contact angle of the film marginally expand (by 6.2-19.1 %). The CMC/Gel film with 3 wt% of CD added depicted strong antioxidant efficacy of 100 % against ABTS and 59.1 % against DPPH and displayed strong antibacterial action that inhibited the progress of Listeria monocytogenes and Escherichia coli by 99.8 %. In addition, when table grapes were packaged using a CMC/Gel composite film containing CD and stored at 4 °C for 24 days, the fruits packed with the composite film maintained excellent external quality and extended the shelf life.

A High-Performance Food Package Material Prepared by the Synergistic Crosslinking of Gelatin with Polyphenol-Titanium Complexes.

This study aims to enhance gelatin film performance in the food industry by incorporating polyphenol-titanium complexes (PTCs) as crosslinkers. PTCs introduce multiple linkages with gelatin, including coordination and hydrogen bonds, resulting in synergistic crosslinking effects. This leads to an increased hydrodynamic volume, particle size, and thermal stability of the gelatin films. Compared to films crosslinked solely by polyphenols or titanium, PTC-crosslinked gelatin films exhibit significant improvements. They show enhanced mechanical properties with a tensile strength that is 1.7 to 2.6 times higher than neat gelatin films. Moreover, these films effectively shield UV light (from 82% to 99%), providing better protection for light-sensitive food ingredients and preserving lutein content (from 74.2% to 78.1%) under light exposure. The incorporation of PTCs also improves film hydrophobicity, as indicated by water contact angles ranging from 115.3° to 131.9° and a water solubility ranging from 31.5% to 33.6%. Additionally, PTC-enhanced films demonstrate a superior antioxidant ability, with a prolonged polyphenol release (up to 18 days in immersed water) and a higher free radical scavenging ability (from 22% to 25.2%). Overall, the improved characteristics of gelatin films enabled by PTCs enhance their performance, making them suitable for various food packaging applications.

Which Gelatin and Antibiotic Should Be Chosen to Seal a Woven Vascular Graft?

Among the vascular prostheses used for aortic replacement, 95% are woven or knitted grafts from polyester fibers. Such grafts require sealing, for which gelatin (Gel) is most often used. Sometimes antibiotics are added to the sealant. We used gelatin type A (GelA) or type B (GelB), containing one of the three antibiotics (Rifampicin, Ceftriaxone, or Vancomycin) in the sealant films. Our goal was to study the effect of these combinations on the mechanical and antibacterial properties and the cytocompatibility of the grafts. The mechanical characteristics were evaluated using water permeability and kinking radius. Antibacterial properties were studied using the disk diffusion method. Cytocompatibility with EA.hy926 endothelial cells was assessed via indirect cytotoxicity, cell adhesion, and viability upon direct contact with the samples (3, 7, and 14 days). Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to visualize the cells in the deep layers of the graft wall. "GelA + Vancomycin" and "GelB + vancomycin" grafts showed similar good mechanical characteristics (permeability~10 mL/min/cm2, kinking radius 21 mm) and antibacterial properties (inhibition zones for Staphilococcus aureus~15 mm, for Enterococcus faecalis~12 mm). The other samples did not exhibit any antibacterial properties. The cytocompatibility was good in all the tested groups, but endothelial cells exhibited the ability to self-organize capillary-like structures only when interacting with the "GelB + antibiotics" coatings. Based on the results obtained, we consider "GelB + vancomycin" sealant to be the most promising.

Effect of electrostatic repulsion on barrier properties and thermal performance of gelatin films by carboxymethyl starch, and application in food cooking.

Carboxymethyl starch (CST) was introduced to improve gelatin films and its practical application as edible high-performance films for food packaging and cooking was also investigated. The gelatin films modified by carboxymethyl starch exhibited the transparent appearance, tensile strength, barrier properties (oxygen, water vapor and UV light), and thermal performance (TGA, thermal shrinkage and heat-sealing strength). Resulting from the effect of electrostatic interaction modes on the properties of films, electrostatic repulsion could surpass electrostatic attraction in improving the tensile strength, oxygen barrier property and thermal stability of the films probably due to extensive physical entanglement without aggregation. Analysis of FTIR, zeta potential, interfacial dilatational rheology, shear rheological properties, XRD, Raman, SEM and AFM suggested that hydrogen bonding and electrostatic repulsion contributed to the excellent performance. The packaged food could also be cooked with the prepared film for porridge; and the film slightly influenced the shear rheological properties of porridge and imposed little effect on the odors (Electronic-Nose) of porridge. Hence, the gelatin films modified by carboxymethyl starch could potentially work as the edible inner packaging or the edible quantitative packaging for food, offer convenience for consumers, reduce the packaging waste and avoid an extra burden on environment.

Evaluating Gelatin-Based Films with Graphene Nanoparticles for Wound Healing Applications.

In this study, gelatin-based films containing graphene nanoparticles were obtained. Nanoparticles were taken from four chosen commercial graphene nanoplatelets with different surface areas, such as 150 m2/g, 300 m2/g, 500 m2/g, and 750 m2/g, obtained in different conditions. Their morphology was observed using SEM with STEM mode; porosity, Raman spectra and elemental analysis were checked; and biological properties, such as hemolysis and cytotoxicity, were evaluated. Then, the selected biocompatible nanoparticles were used as the gelatin film modification with 10% concentration. As a result of solvent evaporation, homogeneous thin films were obtained. The surface's properties, mechanical strength, antioxidant activity, and water vapor permeation rate were examined to select the appropriate film for biomedical applications. We found that the addition of graphene nanoplatelets had a significant effect on the properties of materials, improving surface roughness, surface free energy, antioxidant activity, tensile strength, and Young's modulus. For the most favorable candidate for wound dressing applications, we chose a gelatin film containing nanoparticles with a surface area of 500 m2/g.

Properties of Allicin-Zein Composite Nanoparticle Gelatin Film and Their Effects on the Quality of Cold, Fresh Beef during Storage.

Allicin is a kind of natural antimicrobial active substance, but its water solubility is poor, and it is easy to degrade. In order to improve the stability and bioavailability of allicin, allicin-zein composite nanoparticles (Al-Ze) were prepared by the combination method of antisolvent precipitation and electrostatic deposition, and their characteristic parameters, such as average particle size, polydispersity index (PDI), and ζ-potential, were analyzed. Then, Al-Ze was used as the delivery carrier for the active substance (allicin), and gelatin with good film-forming properties was selected as the film-forming matrix to prepare Al-Ze gelatin films. The optical properties, mechanical properties, and characterization parameters were used to analyze the prepared composite materials; the results confirmed that Al-Ze gelatin film has good mechanical properties and barrier properties. The prepared film was applied to the storage of cold, fresh beef, and the quality change of beef was monitored at 4 °C. The results showed that Al-Ze gelatin film could effectively delay the quality deterioration of beef. This paper provides a new idea and data support for the application of Al-Ze gelatin film in meat storage and fresh-keeping, and offers new insight for the promotion and application of allicin in the food industry.

Multifunctional food packaging materials: Lactoferrin loaded Cr-MOF in films-based gelatin/κ-carrageenan for food packaging applications.

In this study, antimicrobial biocomposite films based on gelatin-κ-carrageenan (Gκ) with 1, 2 and 4 % lactoferrin (L) loaded chromium-based metal-organic frameworks (L@Cr-MOFs) nanoparticles were synthesized by casting methods. The addition of L loaded Cr-MOFs into Gκ based films increased elongation at break from 2.19 to 14.92 % and decreased the tensile strength from 65.1 to 31.22 MPa. L@Cr-MOFs addition reduced swelling index (from 105 to 70.8 %), water solubility (from 61.3 to 34.63 %) and water vapor permeability (from 2.46 to 2.19 × 10-11 g. m/m2. s). When the additional amount was 4 wt%, the Gκ/L@Cr-MOFs films showed antibacterial effects against Escherichia coli and Staphylococcus aureus with the inhibition zone of 19.7 mm and 20.2 mm, respectively. In addition, strawberries preservation trial shown that the Gκ/L@Cr-MOFs films delayed the growth of spoilage molds on the surface of fruits. This research indicated that Gκ/L@Cr-MOFs are promising active packaging materials for the preservation of perishable fruits.

How to effectively and greenly prepare multi-scale structural starch nanoparticles for strengthening gelatin film (ultrasound-Fenton system).

Ultrasound (US) assisted with Fenton (US-Fenton) reaction was developed to efficiently and greenly prepare starch nanoparticles (SNPs) that were employed as nanofillers to enhance gelatin (G) film properties. Compared to Fenton reaction alone, US-Fenton reaction significantly improved preparation efficiency and dispersion of SNPs (p < 0.05). An optimal US-Fenton reaction parameter (300 mM H2O2, ascorbic acid 55 mM, US 45 min) was found to prepare SNPs with uniform sizes (50-90 nm) and low molecular weight (Mn 7.91 × 105 Da). The XRD, FT-IR, and SAXS analysis revealed that the US-Fenton reaction degraded the amorphous and crystalline zones of starch from top to down, leading to the collapse of the original layered structure starch and the progressive formation of SNPs. The different sizes of SNPs were selected to prepare the composite films. The G-SNP3 film (with 50-90 nm SNPs) showed the most outstanding UV blocking, tensile, and barrier properties. Especially, the tensile strength of G-5%SNP3 film (containing 5 % SNPs) increased by 156 % and 6 % over that of G film and G-5%SNP2 film (containing 5%SNPs with 100-180 nm), respectively. Therefore, the nanomaterial was promisingly prepared by the US-Fenton system and provided a strategy for designing and producing nanocomposite films.

Ultrasonic treatment regulates the properties of gelatin emulsion to obtain high-quality gelatin film.

Gelatin emulsion was an important process for preparing gelatin films. A gelatin film with water resistance and ductility could be prepared using gelatin emulsion, whereas the prepared gelatin film has several defects (e.g., low tensile strength and poor thermal stability). This study aimed to modify gelatin emulsion through ultrasonic treatment, then gelatin film was prepared by the modified gelatin emulsion. The results showed that: under the condition of ultrasonic treatment for 12 min at 400 w, zeta potential and viscosity of gelatin emulsion were the largest; thickness, water vapor permeability (WVP) and water solubility (WS) of corresponding gelatin film were the lowest, and the tensile strength (TS), elongation at break (EAB), denaturation temperature (Tm) and enthalpy value (ΔH) of corresponding gelatin film were the highest. The above result suggested that ultrasonic treatment can be used to prepare a gelatin film with better quality by regulating the properties of gelatin emulsion, and a certain correlation was found between the properties of gelatin emulsion and the properties of gelatin film.

Enhancement of water barrier and antimicrobial properties of chitosan/gelatin films by hydrophobic deep eutectic solvent.

Biodegradable chitosan/gelatin (CS/GEL) films have attracted attention as food packaging, but the poor water sensitivity and functional limitations of these films should be addressed. In this study, the hydrophobic deep eutectic solvent (DES, 0-15 %) consisting of thymol and octanoic acid was used to improve the water resistance and antibacterial performance of the CS/GEL composite films. FTIR and SEM analyses revealed a strong interaction between the CS/GEL matrix and DES. The films blended with DES showed increased water contact angle values and thermal stability. Furthermore, the addition of DES resulted in a significant increase in the elasticity and decrease water vapor transmission rate (WVTR). The CS/GEL films blended with 9% DES showed a 38.5% decrease in WVTR compared to those without DES. Additionally, the DES-containing film displayed good antibacterial activity against Staphylococcus aureus and Escherichia coli. Overall, the CS/GEL-DES composite films are expected to contribute an improvement to food packaging.

Antifungal Activity of Camelus-Derived LFA-LFC Chimeric Peptide Gelatin Film and Effect on Oral Bacterial Biofilm.

The objective of this study was to construct lactoferrin (LFA-LFC) chimeric peptide gelatin drug-loaded fiber film by tissue engineering strategy, and study its bacteriostatic effect on oral pathogens (especially Candida albicans) and its effect on biofilm. First of all, LFA-LFC chitosan nanoparticles were prepared firstly, and then fluconazole gelatin (LF/GH/F) film loaded with LFA-LFC was prepared by electrospinning. Scanning electron microscope (SEM), mechanical strength, drug release, cytotoxicity, and real-time PCR were used to test the properties of the synthesized materials. SEM showed that there was the reticular structure for fiber film before and after cross-linking. LF/GH/F film had no obvious cytotoxicity, with good biocompatibility and drug release; real-time PCR and antibacterial test showed that the LF/GH/F film had good antibacterial activity. LF/GH/F film has a good inhibitory effect on oral pathogens, and its mechanism is related to biofilm. The antibacterial experiments of nanofiber membrane in vitro and the effect of bacterial biofilm were carried out. The effect of LF/GH/F on oral microbial flora structure was studied by fluorescence quantitative pest techniques.

Clinical feasibility of absorbable gelatin film adhesion barrier (GM142 "TENALEAF®") in gynecological laparoscopic surgery: Safety assessment for first-in-human use and surgical video.

AIM: To evaluate the safety and operability of the GM142 (TENALEAF®, Medical Division, Gunze Limited, Tokyo, Japan) adhesion barrier applied in patients undergoing surgery for benign gynecologic disease. METHODS: This multicenter open study enrolled 34 patients from November 2018 to October 2019. RESULTS: The primary outcome was the incidence of adverse events (AE) within 12 weeks postoperatively. None of the 30 patients completing the study experienced a life-threatening AE. Thirteen patients (43.3%) suffered 30 mild or moderate AE in total. No intestinal obstruction (0/30) was observed, with the sample size justified by the AdSpray® trial (8/61 patients with AE). No gelatin-specific Immunoglobulin E (IgE) antibodies were induced in the patients. The adhesion barrier could be easily inserted (even via trocar) and positioned. After malfunctions were reported in six patients, the instructions for use were updated for trocar use. CONCLUSION: This study showed the safety and clinical feasibility GM142 as an adhesion barrier.

3D Printed gelatin film with Garcinia atroviridis extract.

Active packaging, such as edible film with antibacterial properties, can help extend the shelf life of food. The research aimed to develop a 3D printed gelatin edible film by using glycerol and Garcinia atroviridis extract (GAE). Mechanical properties of gelatin gel, physical, mechanical, and antimicrobial properties of edible film with glycerol and GAE were determined. Water solubility, total colour difference, and elongation of break of gelatin edible film increased as glycerol concentration increased (0-25% w/w), whereas tensile strength and Young's modulus value decreased from 26.5 to 4.64 MPa and 3.04 to 0.13 MPa, respectively. On the other hand, increasing GAE from 1 to 4% (w/w) increases elongation at break from 40.83 to 98.27%, while decreasing edible film tensile strength and gelatin gel hardness value from 8.94 to 6.21 MPa and 1848.67 to 999.67 g, respectively. Using 20% (w/w) glycerol and 4% (w/w) GAE, the best 3D printed film with low tensile strength (6.21 MPa), high elongation at break (98.27%), and antibacterial activity against S. aureus with 7.23 mm zone of inhibition was developed. It seems to have a great potentiality as an active packaging material for 3D printed gelatin edible film.

Chitosan-Gelatin Films Cross-Linked with Dialdehyde Cellulose Nanocrystals as Potential Materials for Wound Dressings.

In this study, thin chitosan-gelatin biofilms cross-linked with dialdehyde cellulose nanocrystals for dressing materials were received. Two types of dialdehyde cellulose nanocrystals from fiber (DNCL) and microcrystalline cellulose (DAMC) were obtained by periodate oxidation. An ATR-FTIR analysis confirmed the selective oxidation of cellulose nanocrystals with the creation of a carbonyl group at 1724 cm-1. A higher degree of cross-linking was obtained in chitosan-gelatin biofilms with DNCL than with DAMC. An increasing amount of added cross-linkers resulted in a decrease in the apparent density value. The chitosan-gelatin biofilms cross-linked with DNCL exhibited a higher value of roughness parameters and antioxidant activity compared with materials cross-linked with DAMC. The cross-linking process improved the oxygen permeability and anti-inflammatory properties of both measurement series. Two samples cross-linked with DNCL achieved an ideal water vapor transition rate for wound dressings, CS-Gel with 10% and 15% addition of DNCL-8.60 and 9.60 mg/cm2/h, respectively. The swelling ability and interaction with human serum albumin (HSA) were improved for biofilms cross-linked with DAMC and DNCL. Significantly, the films cross-linked with DAMC were characterized by lower toxicity. These results confirmed that chitosan-gelatin biofilms cross-linked with DNCL and DAMC had improved properties for possible use in wound dressings.

Flavor, antimicrobial activity and physical properties of gelatin film incorporated with of ginger essential oil.

Adding essential oil into the gelatin-based film can enhance the antibacterial activity of the film, but excessive amounts of addition will bring the film an unpleasant flavor and reduce its mechanical performance. Hence, we prepared functional gelatin-based films by incorporating low content of ginger essential oil (GEO). The flavor of GEO was not detected from the films containing less than 1% GEO. The antimicrobial activity of films was found to be proportional to GEO content. As GEO content increased from 0 to 1%, the value of water vapor permeability (WVP) and elongation at break (EAB) increased, whereas the value of tensile strength (TS) of film decreased. The Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy analysis revealed the vibration of gelatin film was affected by adding low content of essential oil. Surface morphologies demonstrated oil droplets and a discontinuous structure, and cross-section morphologies proved the formation of a loose structure as GEO was incorporated in the film through SEM. Sensory evaluation revealed that composite films incorporated with 0.5% GEO exhibited the best performance. The resulting films can be used as antimicrobial packaging materials with good physical properties and sensory performance.

Low temperature extrusion blown ε-polylysine hydrochloride-loaded starch/gelatin edible antimicrobial films.

Edible antimicrobial films made from starch/gelatin (S/G) incorporated with different ε-polylysine hydrochloride (ε-PL) contents were developed by low-temperature extrusion blowing process. ε-PL addition reduced the complex viscosity and storage modulus of blends, while promoted the formation of hydrogen bonding among film components. The control film had an A-type crystalline structure, while increasing the ε-PL content promoted its transformation to B-shaped structure. Without ε-PL and under the processing temperature used, the starch granules were not sufficiently gelatinized. However, ε-PL addition significantly enhanced the gelatinization degree. Increasing ε-PL content in S/G films increased film flexibility, water contact angle value, swelling degree, antimicrobial effect, and storage period of fresh bread, but decreased water vapor permeability and tensile strength. S/G film with 4 wt% ε-PL had the highest water contact angle (94°) and elongation at break (149%). This research demonstrates the plasticizing effects of ε-PL and potential of S/G films containing ε-PL for food preservation/packaging.

Antioxidant Films from Cassava Starch/Gelatin Biocomposite Fortified with Quercetin and TBHQ and Their Applications in Food Models.

Edible and active packaging are attractive for use in food packaging applications due to their functionality and sustainability. This research developed new antioxidant active food packaging materials from cassava starch/gelatin (7:3 w/w) composite films with varied antioxidant types (quercetin and tertiary butylhydroquinone (TBHQ)) and concentrations (0-200 mg/200 mL film-forming solution) and evaluated their properties. Antioxidant addition altered the mechanical and barrier properties of the films. At 34% relative humidity (RH), increasing the concentration of quercetin increased the tensile strength and decreased the elongation at break of the composite films. Increasing quercetin and TBHQ contents increased the film water solubility and water vapor transmission rate. Intermolecular interactions between the antioxidants and films, as found in Fourier transform infrared (FT-IR) spectra and XRD micrographs, were related to the changed film functionalities. In food application studies, the cassava starch/gelatin films containing quercetin and TBHQ retarded the oxidation of lard (more than 35 days) and delayed the redness discoloration of pork. Cassava starch/gelatin composite films integrated with quercetin and TBHQ can be utilized as active packaging that delays oxidation in foods.

Sterile Gelatin Film Reduces Cortical Injury Associated With Brain Tumor Re-Resection.

BACKGROUND: Recurrent intracranial tumors frequently require re-resection. Dural adhesions to the cortex increase the morbidity and duration of these revision craniotomies. OBJECTIVE: To describe the use of commercially available sterile gelatin film to prevent meningocerebral adhesions and decrease the rate of surgically induced ischemia from revision craniotomy. METHODS: This retrospective cohort study examined patients with recurrent glioma, meningioma, and metastasis who underwent re-resection at least 30 d following their initial tumor resection. Cortical surface tissue ischemia after re-resection on diffusion-weighted magnetic resonance imaging was compared for patients with (gelatin film group) and without (nongelatin film group) a history of gelatin film placement at the conclusion of their initial tumor resection. RESULTS: A total of 84 patients in the gelatin film group were compared to 86 patients in the nongelatin film group. Patient age, sex, tumor pathology, tumor volume, tumor eloquence, laterality of surgical approach, history of radiotherapy, and time interval between resections did not differ between groups. Radiographic evidence of cortical ischemia following reoperation was less prevalent in the gelatin film group (13.1% vs 32.6%; P < .01). In multivariate logistic regression analysis, no gelatin film (P < .01) and larger tumor size (P = .02) predicted cortical surface ischemia following revision craniotomy. Postoperative complications in the gelatin film and nongelatin film group otherwise did not differ. CONCLUSION: Routine placement of commercially available sterile gelatin film on the cortex prior to dural closure is associated with decreased surgically induced tissue ischemia at the time of revision tumor craniotomy.

Influence of anise (Pimpinella anisum L.) essential oil on the microbial, chemical, and sensory properties of chicken fillets wrapped with gelatin film.

The present study aimed to develop a novel active edible film based on gelatin incorporated with 0, 0.3, 0.6, and 0.9% w/w anise essential oil as a natural preservative and investigate the shelf life extension potential of chicken fillets during 12 days of refrigerated storage. The chicken fillets were wrapped with the essence-free and anise essential oil-loaded gelatin films, and microbial counts, chemical and sensory tests were surveyed during chilled storage. Results showed that aerobic mesophilic bacteria and Pseudomonas spp counts significantly decreased at all levels of anise essential oil during the first week of storage, while psychrotrophs, yeasts, and molds numbers began to reduce at concentrations of 0.6 and 0.9% from day 6. The using of anise essential oil caused a significant decrease of chemical parameters of chicken fillets, and the values of pH, peroxide, thiobarbituric acid reactive substance, and total volatile basic-nitrogen reached from 7.42, 5.7 meq/kg, 2.21 mg malondialdehyde/kg, and 24.94 mg N/100 g for the essence-free wrapped samples to 4.8, 6.35 meq/kg, 1.73 mg malondialdehyde/kg, and 18.78 mg N/100 g for the ones wrapped with 0.9% anise essential oil-loaded gelatin films at the end of storage day. In conclusion, application of gelatin films loaded with 0.6 and 0.9% anise essential oil can be advised for wrapping chicken fillets to prolong the shelf life for at least one week.