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1.
The potential of chitosan (CH) combined with sodium tripolyphosphate (TPP) nanoparticles as a glazing material for shrimp was investigated. Two CH–TPP nanoparticles glazing solutions were prepared: (1). A solution containing CH–TPP nanoparticles with 0.25 (g/100 mL) CH and 0.083 (g/100 mL) TPP (25CH–TPP) and (2). A solution containing CH–TPP nanoparticles with 0.5 (g/100 mL) CH and 0.167 (g/100 mL) TPP (50CH–TPP). Frozen shrimp samples were glazed with 25CH–TPP, 50CH–TPP, CH, TPP, acetic acid, and/or distilled water and then stored at −21 °C for 30 days. Glazed and non-glazed shrimp (NG) samples were analyzed for moisture content, glazing yield, weight loss, color, cutting force, thiobarbituric acid reactive substances (TBARS), yeasts, molds, coliforms and aerobic counts after 1, 3, 5, 20, and 30 d storage. Triplicate experiments were conducted and data statistically analyzed (α = 0.05). Glazed shrimp had higher moisture than NG after 30 d storage. Among the glazes, 25CH–TPP and 50CH–TPP were the most effective in controlling lipid oxidation and reducing aerobic counts and yeasts and molds in shrimp.  相似文献   

2.
The present study examined the effect of natural antimicrobials: chitosan, oregano and their combination, on the shelf-life of modified atmosphere packaged chicken breast meat stored at 4°C. Treatments examined in the present study were the following: M (control samples stored under modified atmosphere packaging), M-O (samples treated with oregano oil 0.25% v/w, stored under MAP), M-CH (samples treated with chitosan 1.5% w/v, stored under MAP) and M-CH-O (treated with chitosan 1.5% w/v and oregano oil 0.25% v/w, stored under MAP). Treatment, M-CH-O, significantly affected mesophilic Total Plate Counts (TPC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Enterobacteriaceae, Pseudomonas spp., and yeasts-moulds during the storage period. Lipid oxidation (as determined by MDA values) of control and treated chicken samples was in general low and below 0.5 mg MDA/kg, showing no oxidative rancidity during the storage period. Addition of chitosan to the chicken samples produced higher (P<0.05) lightness (L*) values as compared to the control samples. The results of this study indicate that the shelf-life of chicken fillets can be extended using, either oregano oil singly, and/or chitosan, by approximately 6 (M-O) and >15 (M-CH and M-CH-O) days. Interestingly, chitosan (M-CH) or chitosan-oregano (M-CH-O) treated chicken samples were sensorially acceptable during the entire refrigerated storage period of 21 days. It is noteworthy that the presence of chitosan in M-CH and M-CH-O samples did not negatively influence the taste of chicken samples, with M-CH samples receiving a higher score (compared to M-CH-O), probably as a result of a distinct and "spicy" lemon taste of chitosan, that was well received by the panelists. Based primarily on sensory data (taste attribute) M-CH and M-O treatments extended the shelf-life of chicken fillets by 6 days, while M-CH-O treatment resulted in a product with a shelf-life of 14 days, maintaining acceptable sensory characteristics.  相似文献   

3.
The present study evaluated the effect of salt, oregano essential oil (EO) and packaging on fresh rainbow trout fillets during storage at 4 °C. Treatments included the following: A1 (control samples, unsalted: air packaged), A2 (salted: air packaged), VP1 (salted, vacuum packaged), VP2 (salted, vacuum packaged with added oregano EO 0.2% v/wt), and VP3 salted, vacuum packaged with added oregano EO 0.4% v/wt). Lactic acid bacteria (LAB) (to a greater extent), followed by H2S-producing bacteria (including Shewanella putrefaciens), Pseudomonas spp. and Enterobacteriaceae reached higher populations in A1, A2 (as compared to VP1, VP2 and VP3) trout samples. Treatments VP1, VP2 and VP3 produced significantly lower (P < 0.05) total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) values as compared to the A1 and A2 samples after day 6 and until end of storage period. Changes in thiobarbituric acid values (TBA) values for A1, A2, VP1, VP2 and VP3 samples were variable, indicative of no specific trend in trout samples, irrespective of packaging in the absence and/or presence of salt and oregano EO. As determined by sensory analysis (overall acceptability attribute) the observed shelf-life of trout fillets was longest for VP2 (16–17 days) followed by VP1 (14 days), A2 (8 days) and control (A1) samples (5 days). The presence of salt and oregano oil (0.2%) in cooked VP1 trout samples produced a distinct but sensorially acceptable pleasant odor, well received by the panellists, in contrast to the combined effect of salt and oregano oil at the higher concentrations (0.4% v/wt) used. Addition of salt (treatment VP1) extended the product's shelf-life by 9 days, whereas the combination of salt, oregano EO (0.2% v/wt) under VP conditions (treatment VP2) resulted in a significant shelf-life extension of trout fillets (11–12 days) according to sensory data, as compared to the control sample, kept under aerobic conditions.  相似文献   

4.
The present study evaluated the effect of thyme essential oil and packaging on fresh Mediterranean swordfish fillets during storage at 4 °C. Treatments in the present study included the following: air (A), modified atmosphere packaging (M), air with thyme oil (AT) and MAP with thyme oil (MT). Of the physicochemical parameters examined, TBA values for A and M swordfish samples were variable, indicative of no specific oxidative rancidity trend, whereas MT treatment inhibited lipid oxidation in swordfish samples during storage. On the basis of microbiological and sensory data, TMA-N and TVB-N limit values of acceptability for Mediterranean swordfish, of ca. 3.72 and 24.5 mg N/100 g, for the initiation of fresh Mediterranean swordfish spoilage, may be proposed. Of the treatments used in the present study, MT and M were the most effective for the inhibition of pseudomonads and H2S-producing bacteria in swordfish. Lactic acid bacteria and Enterobacteriaceae (to a lesser extent) were also found to be part of the natural microbial flora of swordfish, irrespective of packaging treatment. Based primarily on sensory data, the shelf-lives of fresh refrigerated Mediterranean swordfish were 8 and 13 days under aerobic and MAP conditions, respectively. Addition of 0.1% thyme essential oil extended the product’s shelf-life under aerobic conditions by 5 days, whereas the combination of MAP and thyme oil resulted in a significant shelf-life extension of the swordfish fillets, i.e. by approximately 7½ days, according to sensory data, as compared to the control sample.  相似文献   

5.
The physico-mechanical properties of 3 films composed by carvacrol, grape seed extract (GSE) and chitosan in different proportions were studied. The films, prepared by solvent casting technique with the following compositions of the casting solutions in carvacrol, GSE and chitosan: film-1: 9.6 ppm–684 ppm–1.25% w/v, film-2: 60 ppm–400 ppm–1.2% w/v and film-3: 90 ppm–160 ppm–1.24% w/v and were compared to a control (1.25% w/v chitosan) film. Mechanical, structural, barrier and colour properties of the films were evaluated. Film-3 presented the lowest water vapour and carbon dioxide permeabilities (WVP and CO2P) and tensile strength (TS) values and the highest oxygen permeability (O2P), whereas film-1 presented the highest water content and the lowest crystallinity, CO2P, TS and luminosity. These results suggest that in the range studied, carvacrol and GSE affect the film structure and its mechanical properties due to hydrophilic (GSE) and hydrophobic (carvacrol) compounds. This work will help the development of edible films, based on physico-mechanical properties, contributing to food preservation and shelf-life extension.  相似文献   

6.
The objective of this research was to evaluate if chitosan-containing food-grade coatings can control Tyrophagus putrescentiae growth without affecting the sensory attributes of dry-cured hams. Food-grade coating treatments included (1) 0.3% chitosan (CH), (2) 0.6% CH, (3) 0.3% CH + 10% propylene glycol (PG), (4) 0.3% CH + 1% xanthan gum (XG), (5) 0.3% CH + 1% XG + 10% PG, (6) 0.3% CH + 1% carrageenan (CG) + 1% propylene glycol alginate (PGA), and (7) 0.3% CH + 1% CG + 1% PGA + 10% PG. Each coating solution was coated on ham cubes (2.54 × 2.54 × 2.54 cm3, n = 5/treatment) or infused in ham nets and dry-cured ham cubes were wrapped in the ham nets prior to inoculation with 20 adult mites. A randomized complete block design with three replications was utilized to evaluate the efficacy of treatments at controlling mite growth on dry-cured ham. When CH was mixed with XG (0.3% CH + 10% PG + 1% XG, and 0.3% CH + 1% XG) and infused into a net, fewer mites (15.7 and 21.0 mites) were on the ham cubes (P < 0.05) in comparison to the control (211.2 mites). Results indicate that CH has the efficacy to control mites since 1% XG alone did not control mite growth. Difference from control test results indicated that no sensory differences existed (NS) between CH-treated and control ham slices. The addition of chitosan coated nets helped control mite growth when used in conjunction with xanthan gum and propylene glycol and collectively may be useable as part of an integrated pest management plan for ham producers to control mites in their aging houses. Therefore, these coating solutions could be scaled up to evaluate their efficacy in ham aging houses.  相似文献   

7.
Antimicrobial films were prepared by incorporating different concentrations of tea tree essential oil (TTO) into chitosan (CH) films. Film-forming dispersions (FFD) were characterized in terms of rheological properties, particle size distribution and ζ-potential. In order to study the impact of the incorporation of TTO into the CH matrix, the water vapour permeability (WVP), mechanical and optical properties of the dry films were evaluated. The properties of the films were related with their microstructure, which was observed by SEM. Furthermore, the antimicrobial effectiveness of CH–TTO composite films against Listeria monocytogenes and Penicillium italicum was studied.  相似文献   

8.
The 3% chitosan solutions incorporating 10% fish oil (w/w chitosan, containing 91.2% EPA and DHA) with or without the addition of 0.8% vitamin E were prepared. Fresh lingcod (Ophiodon elongates) fillets were vacuum-impregnated in coating solution at 100 mm Hg for 10 min followed by atmospheric restoration for 15 min, dried, and then stored at 2 °C or −20 °C for 3-weeks and 3-months, respectively, for physicochemical and microbial quality evaluation. Chitosan–fish oil coating increased total lipid and omega-3 fatty acid contents of fish by about 3-fold, reduced TBARS values in both fresh and frozen samples, and also decreased drip loss of frozen samples by 14.1–27.6%. Chitosan coatings resulted in 0.37–1.19 and 0.27–1.55 log CFU/g reductions in total plate and psychrotrophic counts in cold stored and frozen stored samples, respectively. Chitosan–fish oil coatings may be used to extend shelf-life and fortify omega-3 fatty acid in lean fish.  相似文献   

9.
Polyelectrolyte hydrogels formed by xanthan gum and chitosan can be used for encapsulation and controlled release of food ingredients, cells, enzymes, and therapeutic agents. In this study, xanthan–chitosan microcapsules were formed by complex coacervation. The effects of initial polymer concentration and chitosan solution pH on the crosslinking density of xanthan–chitosan network were investigated by swelling studies and modulated differential scanning calorimetry (MDSC) analysis. The crosslinking density was found to be less dependent on chitosan solution concentration than xanthan solution concentration and chitosan pH. The capsules were completely crosslinked at all conditions studied when initial xanthan solution concentration was 1.5% (w/v). The changes in the conformation of chitosan chains as chitosan pH approaches 6.2 were found to be important in achieving capsule network structures with different crosslinking densities. These findings indicate that the parameters studied cannot be viewed as independent parameters, as their effects on the degree of swelling are interdependent.  相似文献   

10.
Montmorillonite (MMT) nanoclay and rosemary essential oil (REO) were incorporated into chitosan film to improve its physical and mechanical properties as well as antimicrobial and antioxidant behavior. The MMT weight percent relative to chitosan was varied from 1 to 5 and was activated by three REO levels (0.5%, 1%, and 1.5% v/v), and their impact on physical, mechanical, and barrier properties of the chitosan films was investigated. Total phenolic and antimicrobial activity were also evaluated. Microstructure of chitosan/MMT–REO nanocomposites was characterized through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that incorporating MMT and REO into chitosan improves water gain, water vapor permeability, and solubility of the chitosan film by more than 50%. It was also shown that the combined effect of clay and REO improves significantly the tensile strength and elongation of chitosan (p < 0.05). The XRD and FTIR results confirmed that the improvements are related to the MMT exfoliation and good interaction between chitosan and MMT in the presence of REO. Antimicrobial properties of the films also improved by REO incorporation in 1.5% v/v.  相似文献   

11.
A study of the influence of extraction conditions (pH: 1.5 and 2; temperature: 80 °C and 90 °C; extraction time: 1–3 h), on the yield, chemical composition and purity of the sulphated cell wall polysaccharides ulvan, extracted from the green seaweed Ulva lactuca and precipitated by alcohol is carried out. The alcohol precipitate yields varied from 21.68% to 32.67% (%dw/dw) depending on the pH. At pH 2, the alcohol precipitate yields and the uronic acid recovery from extract juice are higher than those obtained at pH 1.5. Other compounds than ulvan such as cellulose, hemicellulose, proteins and ash are solubilized from the cell walls of Ulva lactuca at both pH, and they are precipitated with alcohol. The alcohol precipitate obtained from different extraction conditions has high uronic acid (20.37%–23.60%) and neutral sugar content (20.09%–29.12%), especially when the conditions (pH, temperature) are drastic. It contains rhamnose (13.35%–15.59%), glucose (2.90%–10.97%), and xylose (2.36%–2.73%). A decrease in the molecular weight of ulvan was observed at acid pH, and for long extraction times. The presence of proteins (1.94%–2.32%) and inorganic material (33.36%–47.15%) in alcohol precipitate prove the lower purity of ulvan extracted and shows that ulvan precipitation with ethanol is not specific.  相似文献   

12.
The effects of Maillard reaction products (MRPs) prepared from chitosan and xylose on the shelf-life of fresh noodles were studied. A model system consisting of chitosan and xylose (1:1.5, w/w) dispersed in distilled water with pH values of 5, 6, 7, 9 was used. The systems were heated to 95 °C for up to 60 h. The development of brown color was more pronounced in the model system with a higher initial pH of the water. The antibacterial activity of chitosan increased at the beginning of the Maillard reaction, and the minimum inhibition concentration (MIC) of chitosan against Bacillus subtilis CCRC 10258 decreased to 50 μg/ml of medium from 250 μg as a result of the Maillard reaction. Gram-positive bacteria were more sensitive to chitosan or its MRPs than Gram-negative bacteria. MRP of chitosan/xylose showed a bactericidal effect against Bacillus subtilis CCRC 10258, while chitosan showed a bacteriostatic effect prior to the occurrence of the Maillard reaction. Addition of 0.05 g/100 ml chitosan (in 0.5 ml/100 ml acetic acid) to fresh noodle formulation resulted in an extension of its shelf-life for 6 more days when stored at 4 °C. However, addition of MRP resulted in the longer shelf-life lasting 14 days when stored at 4 °C.  相似文献   

13.
This study investigated the possible relationship between the encapsulation variables, namely serine protease content (9–50 mg/ml, X1), Arabic gum (0.2–10% (w/w), X2), maltodextrin (2–5% (w/w), X3) and calcium chloride (1.3–5.5% (w/w), X4) on the enzymatic properties of encapsulated serine protease. The study demonstrated that Arabic gum, maltodextrin and calcium chloride, as coating agents, protected serine protease from activity loss during freeze-drying. The overall optimum region resulted in a suitable freeze drying condition with a yield of 92% for the encapsulated serine protease, were obtained using 29.5 mg/ml serine protease content, 5.1% (w/w) Arabic gum, 3.5% (w/w) maltodextrin and 3.4% (w/w) calcium chloride. It was found that the interaction effect of Arabic gum and calcium chloride improved the serine protease activity, and Arabic gum was the most effective amongst the examined coating agents. Thus, Arabic gum should be considered as potential protection in freeze drying of serine protease.  相似文献   

14.
The combined effect of modified atmosphere packaging (MAP: 40% CO2/30% O2/30% N2) and oregano essential oil, on the shelf-life of lightly salted cultured sea bream (Sparus aurata) fillets stored under refrigeration was studied. Quality assessment was based on sensory analysis and biochemical indices determination. Total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) values were higher in sea bream fillets stored in air followed by salted fillets stored in air. For salted sea bream fillets stored under MAP the inhibition in the TVBN and TMAN values was evident in the order MAP < MAP/0.4% (v/w) oregano oil < MAP/0.8% (v/w) oregano oil indicating the preservative effect of oregano oil. Salting had a noticeable preservative effect but produced an increase in the 2-thiobarbituric acid (TBA) values while oregano oil had a strong antioxidant activity giving the lowest TBA values. All raw sea bream fillet samples received acceptable sensory scores during the first 15–16 days of storage. The salted samples remained acceptable up to ca. 20–21 days while the MAP salted samples up to ca. 27–28 days of storage. The oregano oil addition in MAP salted samples yielded a distinct but pleasant flavor and contributed to a considerable slower process of fish spoilage given that the fillets treated with 0.8% (v/w) oregano oil were still sensory acceptable after 33 days of storage. The preservative effect was greater as the oregano oil concentration was greater.  相似文献   

15.
Combining antimicrobial agents such as plant essential oils directly into a food packaging is a form of active packaging. In this work chitosan-based films containing cinnamon essential oil (CEO) at level of 0.4%, .0.8%, and 1.5% and 2% (v/v) were prepared to examine their antibacterial, physical and mechanical properties. Scanning electron microscopy was carried out to explain structure–property relationships. Incorporating CEO into chitosan-based films increased antimicrobial activity. CEO decreased moisture content, solubility in water, water vapour permeability and elongation at break of chitosan films. It is postulated that the unique properties of the CEO added films could suggest the cross-linking effect of CEO components within the chitosan matrix. Electron microscopy images confirmed the results obtained in this study.  相似文献   

16.
Effects of soybean oil (SO), chitosan solution (CH) and their emulsions (SO:CH = 60:40, 50:50 and 40:60 ratios) as coatings on internal quality of eggs stored at 25 and 4 °C, respectively, for 7 and 20 weeks, were evaluated. Eggs coated with SO and SO:CH emulsions maintained grade AA and/or A quality up to 7 weeks at 25 °C and 20 weeks at 4 °C, while noncoated eggs changed from AA to B grade after 2 weeks at 25 °C. Compared with noncoated eggs, shelf‐life of eggs stored at 25 °C was extended for 5 weeks by all SO:CH emulsions. Weight loss of eggs coated with SO:CH emulsions was <3% after 7 weeks at 25 °C and <5% after 20 weeks at 4 °C. SO:CH emulsion is alternatively an effective coating with possible shorter drying times for reducing weight loss and preserving the internal quality of eggs.  相似文献   

17.
In this study, effect of chitosan films combined with orange (Citrus sinensis (L.) Osbeck) peel essential oil on the shelf life of deepwater pink shrimp (Parapenaeus longirostris Lucas 1846) was aimed. Chitosan (CH) and 2% orange peel essential oil (OPEO) combinated chitosan (CH+OPEO) were used for preparing film forming solution. Thickness and microstructure of the films, nutritional composition, sensory and melanosis evaluation, chemical, physical, and microbiological analyses were performed periodically and shelf-life was performed during the storage period of 15 days. The combination of chitosan film with OPEO was effective in prolonging the shelf life of fresh shrimps to 15 days (CH+OPEO), whereas the only chitosan-coated group had a shelf life of 10 days (CH) and the samples packaged without chitosan film had a shelf life of 7 days (control). The results of the study suggested that edible chitosan coatings together with OPEO preserved the shrimps and maintained the shelf life throughout the refrigerated storage period.  相似文献   

18.
The effects of a chitosan (Ch) coating enriched with cinnamon oil (Ch + C) on quality of rainbow trout (Oncorhynchus mykiss) during refrigerated storage (4 ± 1 °C) were examined over a period of 16 days. A solution of Ch (2%, w/v) and Ch + C (2%, w/v Ch + 1.5%, v/v C) was used for the coating. The control and the coated fish samples were analysed periodically for microbiological (total viable count, psychrotrophic count), chemical (TVB-N, PV, TBA), and sensory (raw and cooked fish) characteristics. The results indicated that the effect of the Ch + C coating on the fish samples was to enable the good quality characteristics to be retained longer and to extend the shelf life during the refrigerated storage.  相似文献   

19.
The effect of freezing on viscoelastic behaviour of whey protein concentrate (WPC) suspensions was studied. Suspensions with total protein content of 5% and 9% w/v were prepared from a commercial WPC (unheated suspensions). A group of unheated suspensions was treated at two temperatures (72.5 and 77.5 °C) during selected times to obtain 60% of soluble protein aggregates (heat-treated suspensions). Unheated suspensions and heat-treated suspensions were frozen at −25 °C (frozen unheated and frozen heat-treated suspensions). Frequency sweeps (0.01–10 Hz) were performed in the region of linear viscoelasticity at 10, 20, 30, 40, and 50 °C. Mechanical spectra of all studied suspensions at 20 °C were similar to viscoelastic fluids and complex viscosity increased with the frequency (ω). Elastic (G′) and viscous (G″) moduli were modelled using power law equations (G′ = x, G″ = y), using fitted parameters a, x, b, and y for statistical analysis. Exponent y was the most influenced by freezing, indicating the existence of a higher degree of arrangement in frozen unheated suspensions and a lower degree of arrangement in frozen heat-treated suspensions. Only characteristic relaxation times (inverse of the crossover frequency) of suspensions with 5% w/v of total protein content were significantly influenced by freezing. Time–temperature superposition was satisfactory applied in unheated whey protein concentrate suspensions only in the range of high temperatures (30–50 °C). However, this principle failed over the complete temperature range in most of the frozen suspensions. It is possible that freezing produced an increase in the susceptibility to morphological changes with temperature during the rheological measurements.  相似文献   

20.
The effects of postharvest treatment with chitosan nanoparticles (CSNPs = T1) and Zataria multiflora essential oil (ZEO) incorporated in (ZEO@CSNPs = T2), on the shelf-life extension and antioxidant activities of whole cucumbers during storage were evaluated. Coated and control cucumbers were stored at 10 ± 1 °C with 90-95% RH for 21 days. Measurements of physicochemical and microbial growth were accomplished every 3 days. After 15 days, the fruit decay in the T2 coating was 2% vs. 12 and 97.7% in the T1 coated and uncoated fruit, respectively. Significant differences were obtained for weight loss, firmness, respiration rate, DPPH-radical scavenging activity, reducing power and microbial counts (P < 0.05) during storage. There were significantly higher levels of DPPH-radical scavenging activity and reducing power in T2-treated cucumbers compared with that in the T1-treated followed by the control fruit. In conclusion the ZEO loaded CSNPs coating could improve the quality of cucumber and protect the bioactive components during storage.Industrial relevanceCucumber as a good source of antioxidants is one of the most popular and widely grown vegetable crops in the world. However, it has a short shelf-life (< 14 days) that is mainly related to firmness loss, discoloration, desiccation and fungal rot. The reduction of losses is a major objective of postharvest technology for cucumbers, which tries to utilize safe and efficacious methods to control contamination and the growth of spoiling fungi.On the other hand, the nano-/micro-encapsulation of EOs allows protection of their sensitive bioactive compounds from unfavorable environmental conditions and enhances their bioactivity during food processing and storage. So, in this study a new edible coating, consisting of Zataria multiflora essential oil (ZEO) incorporated into chitosan nanoparticles (CSNPs), was introduced to extend the shelf-life of cucumber as well as protect the bioactive compounds with antioxidant properties.  相似文献   

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