Bilayer coatings for extension of the shelf life of fish fillets: Incorporating seaweed sulfated polysaccharides in chitosan-alginate LbL structures.

The aim of this study was to develop a new active coating of layer-by-layer (LbL) structure composed of alginate (as polyanions) and chitosan (as a polycation) containing sulfated polysaccharide (fucoidan) from Sargassum angustifolium, to protect rainbow trout fillets during refrigerated storage. Chitosan and alginate do not combine with each other as a homogeneous solution, so they are suitable for multilayer coatings. The results demonstrated that coating samples with chitosan and fucoidan significantly improved the quality of fish fillets and extended their shelf life from 6 to 16 days. The chemical values (TBARS and TVB-N) and bacterial growth (total viable count (TVC), total psychrophilic count (PTC), and lactic acid bacteria (LAB)) indicated lower levels in the LbL coating samples containing fucoidan compared to the alginate and control samples. Among the different coating samples, the LbL coating with fucoidan (AChF1) exhibited lower weight loss, improved chromaticity (L*, a*, and b*), and minimal changes in mechanical and sensory evaluations. Based on the findings, AChF1 was the most effective treatment for increasing the shelf life of rainbow trout fillets during refrigerated storage. Therefore, it has potential applications in the food packaging industry.

Development and characterization of a novel biodegradable and antioxidant film based on marine seaweed sulfated polysaccharide.

This research aims to produce an antioxidant and biodegradable polysaccharide film by using macroalgae agar and sulfated polysaccharide. Agar and sulfated polysaccharide (fucoidan) were extracted from Gracilaria corticata and Sargassum angustifolium macroalgae. Five treatments were conducted: (A) agar film (1%, W:V), (C) chitosan film (1%, W:V + 1% acetic acid), (AC) agar:chitosan composite (50:50, V:V), (ACF) AC film with fucoidan (0.5%, W:V), and (ACFA) ACF film with citric acid (30% of the dry weight of film) as a cross-linking agent. Then, 0.75% (V:V) of glycerol was added to all films. The physical, mechanical, antioxidant, color variations, microstructure (SEM), and Fourier transform infrared (FT-IR) spectroscopy were investigated. Based on the results, modifying the agar film with chitosan improved the mechanical strength, humidity, and solubility in the AC composite film (p < .05). Further, adding sulfated polysaccharide and citric acid cross-linking agent to the agar-chitosan composite led to a significant decrease in solubility, humidity, and permeability to water vapor in ACFA films (p < .05), indicating strong cross-linking and reduction in film pores based on the SEM pictures and FTIR results. However, the physical and mechanical properties of the agar-based film obtained from Gracilaria algae can be improved by adding chitosan and citric acid cross-linking agent, and the addition of fucoidan obtained from Sargassum algae has improved its antioxidant properties. This biodegradable film can be a good candidate for preserving perishable products.

Hemostatic efficacy of composite polysaccharide powder (starch-chitosan) for emergency bleeding control: An animal model study.

BACKGROUND: Blood clot formation or hemostasis is vital to minimize blood loss and mitigate the risk of death from severe bleeding. This study investigates the characteristics of a novel hemostatic composite containing chemically modified chitosan and starch for emergency bleeding control. The performance of this novel hemostatic powder was compared with commercially available starch-based (Arista AH) and chitosan-based (Celox) hemostats. METHODS: Hemostatic composite was prepared according to the patent registered by the authors (Patent No. 100865, Iranian Intellectual Property Organization) in Bani Zist Baspar Healda, Inc. (Shiraz, Iran). The properties of the product were surveyed by Fourier-transform infrared spectroscopy and compared with Arista-AH and Celox as commercial counterparts. The cytocompatibility, hemolysis, platelet and red blood cells (RBCs) adhesion, biocompatibility, and biodegradability attributes were evaluated in in vivo and in vitro studies. Hemostatic efficacy was evaluated in 24 healthy 6-month-old male New Zealand white rabbits in lethal and sublethal injuries of femoral artery and veins, respectively. RESULTS: Modification and composition led to a fundamental development in physicochemical characteristics including swelling properties, water absorption, and platelet and RBC adhesion due to improved electrostatic and hydrophilic attributes. The significant superiority in clotting efficiency was confirmed after the application of the composite in 2 models of venous and arterial injury in comparison with common commercial hemostats. CONCLUSION: Simultaneous use of water-absorbing compounds and introducing positively charged functional groups to hemostatic material led to a considerable control of femoral bleeding in emergency conditions. The introduced composite was biodegradable and biocompatible and prompts RBC aggregation and platelet adhesion.

The effect of cross-linker type on structural, antimicrobial and controlled release properties of fish gelatin-chitosan composite films incorporated with ε-poly-l-lysine.

In this study, active antibacterial cross-linked composite films were prepared through incorporating ε-poly-l-lysine (ε-PLL) into Siberian sturgeon gelatin-chitosan mixture. Cross-linking was performed by Glutaraldehyde (G) and/or Cinnamaldehyde (C). The antimicrobial, ε-PLL release, mechanical and morphological properties were then investigated. The addition of G to the biopolymer mixture significantly resulted in lower water vapor permeability, enhanced mechanical strength, lower moisture content, and water solubility. The FTIR spectra indicated the formation of imine bonds in the composite film network. The microstructure of composite films was affected by the cross-linking agent. The films cross-linked by G and C showed smooth and rough surfaces, respectively. C induced very small pores in the cross-section of the composite film. The composite films incorporated with ε-PLL revealed higher and steady-state in vitro antimicrobial properties against food spoilage bacteria. A higher release of ε-PLL and hence higher antibacterial activity was measured in the matrices cross-linked by C than those cross-linked by G. The results showed that the ε-PLL-fortified fish gelatin/chitosan composite films can be considered as a food-packaging material. G and C, as cross-linkers, can improve the structural and antimicrobial properties of this composite film.

The effects of fatty acids chain length on the techno-functional properties of basil seed gum-based edible films.

In this study, the effects of various fatty (including caprylic, lauric, and palmitic) acids on physicochemical, mechanical, and barrier properties of basil seed gum (BSG)-based edible films were investigated. The introduction of fatty acids (FAs) into the BSG-based matrix was confirmed by FT-IR. Increasing the FA chain length resulted in an increase in the thickness and opacity of FA-modified BSG films, while water solubility decreased. The water vapor permeability (WVP) of FA-modified films was significantly (P < 0.05) lower than that of control film. The mechanical properties and color attributes of edible films were improved after incorporating caprylic and lauric acids. SEM micrographs revealed a more homogenous microstructure with a higher surface density in the films incorporated with caprylic acid, while a higher roughness and insoluble particles were observed in those incorporated with lauric, and palmitic acids. Our findings showed that lauric acid is a good candidate for improving the barrier and textural characteristics of BSG-based edible films.

Principal Component Analysis of Time-Related Changes of Some Essential Mineral Contents of Canned Silver Carp (Hypophthalmichthys molitrix) in Different Filling Media.

The kinetic reaction for changes in some essential mineral contents (iron, zinc, calcium, sodium, and copper) of silver carp canned in sunflower oil, soybean oil, olive oil, and brine as filling media was assessed after a short- (1 year) and long-term storage (3, 5, and 7 years). The mineral nutrition value of cans was also determined to take into account the changes in estimated daily intake (EDI) of elements during storage and then clustered by principal component analysis (PCA). Results revealed that the reduction of trace elements in brine was higher than in other filling media due to formation of insoluble metal hydroxide. No changes were detected in the mineral content of cans after 1-year storage in comparison to fresh cans, while the content and daily intake of zinc, iron, calcium, copper, and sodium were significantly decreased in all filling media after 3, 5, and 7 years of storage. The first-order reaction model was detected for reduction of mineral contents in filling medium. Post-storage daily intake of iron, sodium, calcium, zinc, and copper was 0.06 up to 0.18, 1.9 up to 9.7, 1.8 up to 9.1, 0.02 up to 0.10, and 0.004 up to 0.02 mg/day/person, respectively. Filling medium had significant effects on estimated daily intake of zinc, sodium, calcium, and copper in long-term sorted cans. PC1 and PC2 explained 93.7% of the total variance of the dataset, contributing 68.7 and 20.5%, respectively.

Effect of various postmortem processing times and blanching methods on quality of rainbow trout (Oncorhynchus mykiss) waste oil.

Oil extracted from fish waste is considered as a value-added product. The effect of postmortem processing times (0, 3, 6, and 9 hr) and blanching methods (sodium chloride, pH shift, and high temperature) on the extracted oil from rainbow trout viscera was studied. Blanching was applied six hours prior to oil extraction to counteract the effects of delayed processing time and increasing the oil stability. Autolysis by digestive enzymes is main culprit of higher contents of free fatty acids, lipid oxidation, saponified compound, and saturation degrees in case of postponed oil extraction. Results showed that PV was increased after pH shift and high temperature blanching, while there were no significant differences by using salt blanching. The lowest amount of TBA, AV, Totox, and saponification index was observed in salt blanched treatment. The colorimetric values including L*, b*, and whiteness index were decreased after pH shift, whereas redness was increased. Unfavorable coloration could be attributed to the lipid oxidation process that giving rise nonvolatile decomposition products with carbonyl groups. Our results indicated that salt blanching could reduce the effects of delayed processing time and lead to higher quality value-added product from rainbow trout viscera.

Development of bioactive composite films from chitosan and carboxymethyl cellulose using glutaraldehyde, cinnamon essential oil and oleic acid.

In the present research the effect of incorporating cinnamon essential oil (CEO), oleic acid (OA) and glutaraldehyde (GL) on antimicrobial, antioxidant, mechanical, physical and morphological properties of chitosan-carboxymethyl cellulose composite films were investigated. Cross-linking effect of GL (as determined by FTIR analysis) significantly resulted in higher mechanical strength and lower water vapor permeability (WVP). Cross-linked films incorporated with CEO revealed higher and steady state antioxidant activity as well as in vitro antimicrobial properties against Listeria monocytogenes and Pseudomonas aeruginosa. Thickness, elongation at break (EAB) and WVP increased by including OA; however, water solubility significantly decreased. Color properties and microstructure of composite films were significantly affected by the additives as confirmed by SEM analyses. We showed that the antimicrobial, antioxidant, mechanical and physical properties of chitosan-carboxymethyl cellulose composite films could be improved via incorporating CEO and GL to the film matrix.

Shelf-life enhancement of whole rainbow trout (Oncorhynchus mykiss) treated with Reshgak ice coverage.

The effect of ice coverage comprised of Reshgak extract and Reshgak essential oil on shelf-life extension of chilled whole rainbow trout (Oncorhynchus mykiss) was evaluated. Chemical (peroxide value (PV), thiobarbituric acids (TBA), total volatile nitrogen base (TVB-N), and free fatty acids (FFA)), microbiological (total viable count (TVC) and psychrotrophic viable count (PVC)), and sensory evaluations (texture, color, flavor, and general acceptance) were investigated every 4 days during a 20-day storage period. Results revealed that the effect of both icing systems led to considerably lower bacterial counts and chemical indices in comparison with the traditional ice coverage without such phytogenic. According to sensory analyses, fish stored in ice containing Reshgak essential oil had a longer shelf-life (>16 days) and those stored in ice medium included with Reshgak extract possessed a shelf-life of 16 days, whereas lot stored in traditional ice showed a shorter shelf-life of 12 days.

Comparison of methods to improve induction of spermiation in wild-caught carp (Cyprinus carpio carpio), a threatened species from the Caspian Sea basin.

Wild carp (Cyprinus carpio carpio) forms the basis of an important fishery in the Southern Caspian Sea Basin which is increasingly underpinned by the release of cultured juveniles. A significant bottleneck to hatchery-rearing of juveniles is the spermiation of male broodstock. Therefore, four approaches to improving spermiation were investigated. The effectiveness of two delivery methods for the sustained release of salmon gonadotropin releasing hormone analogue (sGnRHa; i.e., via intramuscular cholesterol pellet vs emulsion injection) on the spermiation success and duration, sperm quality and quantity over 14days in wild-caught carp were compared to single injection of sGnRHa with Pimozide(®) (Linpe method) or carp pituitary extract (CPE). The consequence of the spermiation treatments on resulting embryonic quality was evaluated for subsequent fertilization and hatching success from wild male carp (mean weight±S.D. 1021±112g). All hormonal treatments, except for Linpe method, led to 100% spermiation of treated fish compared to only 25% in the control with no hormone intervention. The duration of spermiation, as well as the various quantitative variables of the sperm and the mean total sperm production were all generally improved with the sustained hormone delivery compared with the acute treatments. The GnRHa-FIA was the most effective method for improving spermiation.

Concentration of some heavy metals in rice types available in Shiraz market and human health risk assessment.

This investigation was conducted to survey the levels of some heavy metals such as cadmium, lead, chromium, nickel and cobalt in domestic cultivated and imported rice sold on the Shiraz - Iran markets. The potential human health risk assessment was conducted by considering estimated weekly intake (EWI) of toxic metals from eating rice and compared calculated values with provisional tolerable weekly intake (PTWI). The mean values for lead and cadmium in domestic cultivated and imported rice were considerably higher than allowable limits set by FAO/WHO. In combination of recent rice consumption data, the estimated weekly intakes of toxic element were calculated for Iranian population. EWI for cadmium, nickel, chromium through imported and domestic cultivated rice consumption was lower than the PTWI. The EWI for lead were considerably higher than other measured toxic metals. The highest mean level of EWI for lead was observed in some imported rice samples (25.76 µg/kg body weight).

Comparative essential oil composition of aerial parts of Tanacetum dumosum Boiss. from Southern Zagros, Iran.

The essential oils of leaves and flowers of Tanacetum dumosum Boiss., an endemic medicinal shrub, were extracted by using hydrodistillation method and analysed using GC and GC-MS. A total of 43 and 44 compounds were identified in the essential oils from the leaves and flowers of T. dumosum, respectively. The major chemical constituents of leaves oil were borneol (27.9%), bornyl acetate (18.4%), 1,8-cineol (17.5%), α-terpineol (5.3%), cis-chrysanthenyl acetate (3.3%), camphene (2.7%) and terpinene-4-ol (1.9%), while the main components of the flower oil were isobornyl-2-methyl butanoate (41.1%), trans-linalyl oxide acetate (11.9%), 1,8-cineole (7.7%), thymol (4.2%), linalool (3.9%), camphor (2.9%), isobornyl propanoate (2.9%), α-terpineol (2.1%) and caryophyllene oxide (2.0%). Major qualitative and quantitative variations for some main chemical compounds among different aerial parts of T. dumosum were identified. High contents of borneol, bornyl acetate, 1,8-cineol and linalool in the leaves and flowers of T. dumosum show its potential for use in the food and perfumery industry.

Impact of parameter variation in fabrication of nanostructure by atomic force microscopy nanolithography.

In this letter, we investigate the fabrication of Silicon nanostructure patterned on lightly doped (10(15) cm(-3)) p-type silicon-on-insulator by atomic force microscope nanolithography technique. The local anodic oxidation followed by two wet etching steps, potassium hydroxide etching for silicon removal and hydrofluoric etching for oxide removal, are implemented to reach the structures. The impact of contributing parameters in oxidation such as tip materials, applying voltage on the tip, relative humidity and exposure time are studied. The effect of the etchant concentration (10% to 30% wt) of potassium hydroxide and its mixture with isopropyl alcohol (10%vol. IPA ) at different temperatures on silicon surface are expressed. For different KOH concentrations, the effect of etching with the IPA admixture and the effect of the immersing time in the etching process on the structure are investigated. The etching processes are accurately optimized by 30%wt. KOH +10%vol. IPA in appropriate time, temperature, and humidity.

Effect of frying in different culinary fats on the fatty acid composition of silver carp.

The influence of frying with four different oils (sunflower oil, soybean oil, olive oil, and corn oil) on the fatty acid composition of silver carp was evaluated. The fat content of the fillets increased after frying while the moisture content decreased in all evaluated samples. Mean saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, ∑ω3, and ∑ω6 contents of raw fish were 26.1 ± 0.5, 52.1 ± 1.1, 15.1 ± 0.6, 8.9 ± 0.1, and 6.1 ± 0.4%, respectively. Frying led to exchange of fatty acids between the silver carp lipid and frying fats. As a result of interactions, MUFA, PUFA, ∑ω6, and PUFA/SFA ratio of samples fried in sunflower, soybean, and corn oil significantly increased while the amounts of SFA decreased. Frying had a negative effect on the ∑ω3/ω6 ratio but reduction in olive oil-fried samples is the least among the other samples. Except in soybean oil, long-chain ω3-PUFA content of samples was not affected by frying.