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1.
Food Chem ; 350: 129196, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33607409

RESUMO

Histamine poisoning from seafood is a significant public health and safety concern. To detect histamine sensitively and accurately, a novel competitive sandwich immunoassay using a modified biotin-streptavidin system coupling with polylysine was developed. Using this strategy, a sandwich ELISA with an IC50 value of 112.8 ng mL-1 and a broad linear range of 11.7-1500 ng mL-1 with a correlation coefficient of 0.9942 was validated. Without any sample derivatization procedure, the recovery of histamine ranged from 80.19% to 108.3% with a coefficient of variation of 1.43-11.7% in tuna, prawn and crab. The sandwich ELISA had a detectionlimit of 5.86 ng mL-1, which was 15-fold lower than an indirect competitive ELISA (ic-ELISA). This simple, sensitive and accurate method can be applied to detect histamine in routine seafood samples.


Assuntos
Biotina/metabolismo , Braquiúros/química , Decápodes/química , Ensaio de Imunoadsorção Enzimática/métodos , Histamina/análise , Estreptavidina/metabolismo , Atum , Animais , Análise de Alimentos , Limite de Detecção , Alimentos Marinhos/análise
2.
Carbohydr Polym ; 252: 117192, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33183634

RESUMO

Microorganisms which adhere to the surfaces of indwelling medical implants develop into a sessile microbial community to form monomicrobial or polymicrobial biofilms. Staphylococcus epidermidis and Candida albicans are the most common pathogens co-isolated from device mediated infections. Hence development of catheters coated with anti-fouling substances is of great interest. In this current study, chitosan, extracted from the shells of marine crab Portunus sanguinolentus was coated over the surface of the urinary catheters and checked for its efficacy to inhibit the adherence of both mono and mixed species biofilms. The Extracted Chitosan (EC) coated catheters showed profound activity in reducing the preformed biofilms and the other virulence factors of the pathogens like slime production in S. epidermidis and yeast to hyphal swtich in C. albicans. Furthermore, qPCR analysis showed that EC could downregulate the virulence genes in both the pathogens when grown as monospecies and mixed species biofilms.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Quitosana/farmacologia , Staphylococcus epidermidis/efeitos dos fármacos , Cateteres Urinários/microbiologia , Animais , Braquiúros/química
3.
J Agric Food Chem ; 69(1): 428-436, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33377774

RESUMO

In order to reduce the immunoreactivity of sarcoplasmic calcium-binding protein (SCP), site-directed mutations were used to replace key amino acids in the conformational epitopes and calcium-binding sites. The mutant SCPs (mSCPs) were expressed in Escherichia coli, and their immunoreactivities were analyzed using iELISA and basophil activation assays. Furthermore, the structural changes of mSCPs were determined from the circular dichroism spectra. The iELISA results showed that mSCPs could effectively inhibit the binding of wild-type SCP (wtSCP) to sensitive serum, with inhibition rates that reached 90%. Moreover, mSCPs could downregulate the expression levels of CD63 and CD203c on the basophil surface. Compared with wtSCP, the peak values were significantly changed, and the calcium binding ability was impaired, which explained the decline in immunoreactivities of the mSCPs. All of the data confirmed that this approach was effective in reducing the immunoreactivity of SCP and could be applied to other shellfish allergens.


Assuntos
Proteínas de Artrópodes/genética , Proteínas de Artrópodes/imunologia , Braquiúros/imunologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/imunologia , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/química , Basófilos/imunologia , Braquiúros/química , Braquiúros/genética , Proteínas de Ligação ao Cálcio/química , Dicroísmo Circular , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Humanos , Imunoglobulina E/imunologia , Mutagênese Sítio-Dirigida , Alinhamento de Sequência , Hipersensibilidade a Frutos do Mar/imunologia
4.
PLoS One ; 15(12): e0243734, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33370322

RESUMO

The cycling and fate of polycyclic aromatic hydrocarbons (PAHs) is not well understood in estuarine systems. It is critical now more than ever given the increased ecosystem pressures on these critical coastal habitats. A budget of PAHs and cycling has been created for Galveston Bay (Texas) in the northwestern Gulf of Mexico, an estuary surrounded by 30-50% of the US capacity of oil refineries and chemical industry. We estimate that approximately 3 to 4 mt per year of pyrogenic PAHs are introduced to Galveston Bay via gaseous exchange from the atmosphere (ca. 2 mt/year) in addition to numerous spills of petrogenic PAHs from oil and gas operations (ca. 1.0 to 1.9 mt/year). PAHs are cycled through and stored in the biota, and ca. 20 to 30% of the total (0.8 to 1.5 mt per year) are estimated to be buried in the sediments. Oysters concentrate PAHs to levels above their surroundings (water and sediments) and contain substantially greater concentrations than other fish catch (shrimp, blue crabs and fin fish). Smaller organisms (infaunal invertebrates, phytoplankton and zooplankton) might also retain a significant fraction of the total, but direct evidence for this is lacking. The amount of PAHs delivered to humans in seafood, based on reported landings, is trivially small compared to the total inputs, sediment accumulation and other possible fates (metabolic remineralization, export in tides, etc.), which remain poorly known. The generally higher concentrations in biota from Galveston Bay compared to other coastal habitats can be attributed to both intermittent spills of gas and oil and the bay's close proximity to high production of pyrogenic PAHs within the urban industrial complex of the city of Houston as well as periodic flood events that transport PAHs from land surfaces to the Bay.


Assuntos
Baías/química , Monitoramento Ambiental/estatística & dados numéricos , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Organismos Aquáticos/química , Organismos Aquáticos/metabolismo , Atmosfera/química , Braquiúros/química , Braquiúros/metabolismo , Peixes/metabolismo , Sedimentos Geológicos/química , Golfo do México , Ostreidae/química , Ostreidae/metabolismo , Poluição por Petróleo/estatística & dados numéricos , Texas , Poluentes Químicos da Água/análise
5.
Artigo em Inglês | MEDLINE | ID: mdl-32570963

RESUMO

(1) Although suffers from intense pollution inputs, Guanabara Bay, the most socioeconomically and environmentally important estuary in Rio de Janeiro, Brazil, is still home to a diverse fauna, including several fish and crab species consumed by humans. The bay presents high sedimentation rates and sediment contamination, further aggravated by dredging processes carried out in recent years. In this context, this study aimed to verify the effect of the dredging process on total mercury (THg) concentrations at Guanabara Bay through swimming crab assessments sampled before (2016), during (2017), and after (2018) the dredging process, and mainly, if the detected concentrations can be harmful to consumer health; (2) Methods: Swimming crab samplings were carried out at the same time and sampling points in 2016, 2017 and 2018 and the total Hg was determined using a Direct Mercury Analyzer (DMA-80, Milestone, Bergamo, Italy); (3) Results: Increased Hg concentrations were observed during the dredging process, decreasing to lower values, close to the initial concentrations, at the end of the process. Some of the investigated abiotic factors favor Hg dynamics in the aquatic environment, while others were positively altered at some of the assessed sampling areas at the end of the dredging process; (4) Conclusions: Although crab Hg levels were below maximum permissible limits for human consumption, it is important to note that these animals are significantly consumed around Guanabara Bay, which may lead to public health issues in the long term.


Assuntos
Braquiúros , Sedimentos Geológicos , Mercúrio , Poluentes Químicos da Água , Animais , Braquiúros/química , Brasil , Monitoramento Ambiental , Estuários , Humanos , Itália , Mercúrio/análise , Natação , Poluentes Químicos da Água/análise
6.
Sci Rep ; 10(1): 8454, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32439940

RESUMO

Egg oil from Portunus trituberculatus (Pt-egg oil) can overcome insulin resistance resulting from abundant bioactive lipids. However, its effects on obesity and gut microbiota were unclear. Here, we evaluated whether Pt-egg oil could improve obesity and gut microbiota or not in high-fat diet feeding mice. Results exhibited that Pt-egg oil markedly reduced body weight and adipose weight gain, improved lipid accumulation and circulatory cytokines, inhibited epididymal adipose cell size. Moreover, Pt-egg oil modified gut microbiota, involving decreases in the ratio of Firmicutes to Bacteroidetes, Proteobacteria, Actinobacteria, and increase in Verrucomicrobia phylum. Pt-egg oil reduced serum and fecal lipopolysaccharide (LPS) levels and down-regulated Toll-like receptor 4 pathway in both epididymal adipose and liver tissues. Meanwhile, Pt-egg oil increased short chain fatty acids and up-regulated of G-protein-coupled receptors in both epididymal adipose and liver tissues. These suggest that Pt-egg oil could be alternative food supplement for the prophylactic effects on anti-obesity and improvement in human gut health.


Assuntos
Braquiúros/química , Microbioma Gastrointestinal/efeitos dos fármacos , Resistência à Insulina , Obesidade/prevenção & controle , Óleos/farmacologia , Animais , Glicemia/análise , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/patologia
7.
J Chromatogr A ; 1621: 461029, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32192704

RESUMO

The aim of the present study was to compare the enantioseparation performance of chiral stationary phases (CSPs) which were derived from chitosans of different sources and molecular weights. Therefore, chitosans of shrimp and crab shells were prepared. The viscosity-average molecular weights of the chitosans both prepared from shrimp and crab shells were 2.8 × 105 and 1.4 × 105. The chitosans were isobutyrylated yielding isopropylcarbonyl chitosans which were then derivatized with 4-methylphenyl isocyanate to provide chitosan 3,6-bis(4-methylphenylcarbamate)-2-(isobutyrylamide)s. The chitosan 3,6-bis(4-methylphenylcarbamate)-2-(isobutyrylamide)s were used as chiral selectors (CSs) with which the corresponding CSPs were prepared. With the same chiral analytes and under the same mobile phase conditions, the enantioseparation capability of the CSPs was evaluated by high-performance liquid chromatography. In two CSs prepared from the same source, the one with higher molecular weight showed better enantioseparation capability; in two CSs prepared with the chitosans of the same molecular weight, the one derived from shrimp shell exhibited better performance. With regard to the two shrimp chitosan CSs, most of chiral analytes interacted more strongly with the one with lower molecular weight, and an opposite trend was found for the two crab chitosan CSs. Based on the results observed in the present study and in previous work, we believe that the influence of molecular weight on CSP enantioseparation performance is related to the substituent introduced in the CS molecule.


Assuntos
Quitosana/química , Cromatografia Líquida de Alta Pressão , Animais , Braquiúros/química , Quitosana/análogos & derivados , Peso Molecular , Penaeidae/química , Estereoisomerismo
8.
Food Chem ; 319: 126432, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32172045

RESUMO

The main aim of the present study was the measurement of nickel metal ion in the real samples of crab, oyster and rice by the designed magnetic nano adsorbent silk fibroin-EDTA ligand (SF-Fe3O4-EDTA). Due to the structure of silk fibroin (possessing lots of functional groups which are suitable for attachment of ligands and high surface area), it was used in the structure of fabricated nano-adsorbent. To follow the fabrication processes of the magnetic nano-adsorbent, different techniques of fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Visible), vibrating sample magnetometer (VSM), and field emission scanning electron microscopy (FE-SEM) were used. The optimization processes were performed with the chemometric method of response surface modeling with sufficient accuracy and precision. Using this chemometric method, the optimum values of pH, absorption time, the concentration of nano-adsorbent and temperature were calculated to be 6, 21 min, 4 mg L-1 and 28 °C, respectively. Due to the magnetic nature of the constructed nano-adsorbent, a magnet bar was used to separate the nano-adsorbent from the solution and then inject to the furnace atomic absorption device. Using the magnetic nano-adsorbent of silk fibroin-EDTA ligand and furnace atomic absorption a detection limit of 0.0017 µg L-1 and a linear range of 0.0030-5.0 µg L-1 for determination of nickel metal ion were obtained. The determination of nickel metal ion in the crab tissue, oyster tissue and rice samples were performed and the obtained results revealed the successful applicability of the designed method for determination of nickel metal ion in the real samples.


Assuntos
Braquiúros/química , Fibroínas/química , Níquel/análise , Oryza/química , Frutos do Mar , Animais , Ácido Edético/química , Ligantes , Limite de Detecção , Magnetismo , Imãs , Espectrofotometria Atômica
9.
Bull Environ Contam Toxicol ; 104(4): 418-422, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32128604

RESUMO

This short note aims to report in detail a preliminary assessment of the concentrations of Cd, Hg and Pb in tissues of blue crabs Callinectes danae collected from the Cananéia-Iguape-Peruíbe estuarine complex (CIP), in the South of São Paulo State coast, Brazil. In October 2014, blue crabs were collected from CIP. Tissues were removed by dissection and metal determination was performed by GF-AAS and CV-AAS. According to statistical analysis, Pb and Cd concentrations in gills were significantly higher than those found in muscles and hepatopancreas, respectively. There were no significant differences in Hg concentrations between samples. Cd, Hg and Pb concentrations in gills and hepatopancreas were lower than those reported in a previous study performed at CIP. However, Cd concentration in hepatopancreas was higher than the Brazilian limit for consumption and new efforts to monitor Cd concentrations in C. danae tissues must be performed.


Assuntos
Monitoramento Biológico/métodos , Braquiúros/química , Estuários , Metais Pesados/análise , Mineração , Poluentes Químicos da Água/análise , Animais , Brasil , Brânquias/química , Hepatopâncreas/química , Músculos/química
10.
Sci Rep ; 10(1): 3720, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111891

RESUMO

Many factors affect the flavor of crabs. However, impact of temperature on flavor has not been reported. Here, we examined Scylla paramamosain collected within the main four producing areas in China from north sampling point (NP) and south sampling point (SP), respectively. The contents of flavouring-related substances in hepatopancreas, muscles and gonads were determined by high-performance liquid chromatography (HPLC). Meanwhile, high-throughput sequencing of 16S RNA gene was used to reveal the diversity distribution of gut microbiota at each sample collection point. Comparisons among flavor substances of edible parts, the implied higher temperature in SP may be beneficial to the accumulation of flavor substances in gonads, while lower temperature in NP may be beneficial to the accumulation of flavor substances in muscles and hepatopancreas. The gut microbiota of crabs, was analyzed via 16S rRNA gene sequencing. The results of gut microbiota showed that there were significant differences in the distribution of gut microbiota in NP and SP. The microbiota composition of SP has a high distribution richness and no absolute dominant bacteria, while NP has absolute dominant bacteria and its microbiota richness was lower than SP. The results of redundancy analysis (RDA) showed that there was a significant correlation between temperature and the relative abundance of gut microbiota, and a significant correlation between gut microbiota and the content of flavor substances. This study indicates that temperature may be one of the main factors for the differences of flavor substances between SP and NP, which was most probably mediated by gut microbiota. Further exploration is needed with laboratory experiments in which the environment is more precisely controlled if these views are to be determined.


Assuntos
Braquiúros/química , Braquiúros/microbiologia , Microbioma Gastrointestinal , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , China , Ecossistema , Aromatizantes/química , Hepatopâncreas/química , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Músculo Esquelético/química , Frutos do Mar/análise , Frutos do Mar/microbiologia , Paladar , Temperatura
11.
Carbohydr Polym ; 236: 116046, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32172860

RESUMO

Hydrogels properties open up many possibilities for medical applications. In the present study, protein drug insulin was selected as a model drug to test the in vitro release behavior of hydrogels based on blue crab chitosan (Cs) and red marine macroalga Falkenbergia rufolanosa polysaccharide (FRP). The FRP/Cs composed hydrogels were characterized in terms of structural, morphological, thermal and antioxidant properties. Data revealed that FRP addition enhanced the water holding capacity and the water uptake percentages, as well as the textural behavior. Moreover, the prepared hydrogels are simultaneous sensitive to pH, ionic strength and temperature as demonstrated in the swelling ratio test. Additionally, hydrogels at pH 1.2 PBS underwent greater degradation, compared to samples immersed in pH 7.4 PBS. Similarly, the kinetics of insuline release, through the FRP/Cs composed hydrogels exhibited higher released amounts in acidic systems. Through this study, the prepared hydrogels provided suitable and promising microenvironment in drugs delivery.


Assuntos
Quitosana/química , Portadores de Fármacos/química , Hidrogéis/química , Insulina/química , Polissacarídeos/química , Animais , Braquiúros/química , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/química , Portadores de Fármacos/síntese química , Liberação Controlada de Fármacos , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Hidrogéis/síntese química , Concentração de Íons de Hidrogênio , Rodófitas/química
12.
Mar Drugs ; 18(1)2020 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-31963764

RESUMO

Chitin and its derivative chitosan are popular constituents in wound-treatment technologies due to their nanoscale fibrous morphology and attractive biomedical properties that accelerate healing and reduce scarring. These abundant natural polymers found in arthropod exoskeletons and fungal cell walls affect almost every phase of the healing process, acting as hemostatic and antibacterial agents that also support cell proliferation and attachment. However, key differences exist in the structure, properties, processing, and associated polymers of fungal and arthropod chitin, affecting their respective application to wound treatment. High purity crustacean-derived chitin and chitosan have been widely investigated for wound-treatment applications, with research incorporating chemically modified chitosan derivatives and advanced nanocomposite dressings utilizing biocompatible additives, such as natural polysaccharides, mineral clays, and metal nanoparticles used to achieve excellent mechanical and biomedical properties. Conversely, fungi-derived chitin is covalently decorated with -glucan and has received less research interest despite its mass production potential, simple extraction process, variations in chitin and associated polymer content, and the established healing properties of fungal exopolysaccharides. This review investigates the proven biomedical properties of both fungal- and crustacean-derived chitin and chitosan, their healing mechanisms, and their potential to advance modern wound-treatment methods through further research and practical application.


Assuntos
Agaricales/química , Braquiúros/química , Quitina/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Quitosana/farmacologia , Humanos
13.
Sci Rep ; 10(1): 554, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953478

RESUMO

When a range-shifting species colonizes an ecosystem it has not previously inhabited, it may experience suboptimal conditions that challenge its continued persistence and expansion. Some impacts may be partially mitigated by artificial habitat analogues: artificial habitats that more closely resemble a species' historic ecosystem than the surrounding habitat. If conditions provided by such habitats increase reproductive success, they could be vital to the expansion and persistence of range-shifting species. We investigated the reproduction of the mangrove tree crab Aratus pisonii in its historic mangrove habitat, the suboptimal colonized salt marsh ecosystem, and on docks within the marsh, an artificial mangrove analogue. Crabs were assessed for offspring production and quality, as well as measures of maternal investment and egg quality. Aratus pisonii found on docks produced more eggs, more eggs per unit energy investment, and higher quality larvae than conspecifics in the surrounding salt marsh. Yet, crabs in the mangrove produced the highest quality larvae. Egg lipids suggest these different reproductive outcomes result from disparities in the quality of diet-driven maternal investments, particularly key fatty acids. This study suggests habitat analogues may increase the reproductive fitness of range-shifting species allowing more rapid expansion into, and better persistence in, colonized ecosystems.


Assuntos
Braquiúros/fisiologia , Ovos/análise , Lipídeos/análise , Animais , Braquiúros/química , Ecossistema , Aptidão Genética , Oviposição , Áreas Alagadas
14.
Ecotoxicol Environ Saf ; 191: 109986, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31806251

RESUMO

The presence of heavy metals (HMs) in the environment can increase their risk of transfer to the food chain. The present study was conducted to investigate the bioaccumulation of HMs including Hg, Cd and Ni in soft and hard tissues of sentinel crab (Macrophthalmus depressus Rüppell, 1830) in sediments of Mousa Bay in northwest of the Persian Gulf. The average (mean ± SD) amounts of Hg, Cd and Ni in the sediments were 6.27 ± 3.66, 3.8 ± 1.48 and 71.6 ± 5.09 µg/g, whereas the relevant amounts for soft tissues were 6.16 ± 4.64, 3.3 ± 1.7 and 19.7 ± 3.96 µg/g, and for hard tissues were, 2.9 ± 1.67, 3.5 ± 1.35 and 10.44 ± 3.1 µg/g, respectively. Accordingly, soft tissues of the crab could be suitable bioindicators of Hg and Cd, whereas the hard tissues could be used as Cd bioindicator. Since the bioaccumulation of Ni was the most, it might have a higher risk among the metals to enter the food chain in the region.


Assuntos
Braquiúros/química , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Baías , Bioacumulação , Cádmio/análise , Biomarcadores Ambientais , Cadeia Alimentar , Oceano Índico , Mercúrio/análise , Níquel/análise
15.
Environ Sci Pollut Res Int ; 27(4): 4044-4057, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31823264

RESUMO

The environmental health of Buenaventura Bay, a highly impacted tropical estuary, is influenced by numerous human activities, including mining upstream. Large- and small-scale fishing plays an important role in the local economy, so we investigated the dynamic processes of bioaccumulation of mercury at basal trophic levels. Four samples were taken at each of the four locations in Buenaventura Bay during each of the four seasons of 2015. We measured the total mercury content (T-Hg, dry weight) in sediments and in muscle tissue across 17 macroinvertebrate species. The most abundant were the blue crab (C. arcuatus) and the mantis shrimp (S. aculeata aculeata). Blue crab showed an average muscle T-Hg value ​​exceeding the limit of 0.2 g·g-1, which is the maximum T-Hg level suggested for food consumption by vulnerable humans and populations: pregnant women, children, and the community that feeds from this source of protein on a daily basis. It was found that, 6.22% of individuals exceeded the 0.5 g·g-1 level, which is the maximum T-Hg level suggested for food consumption by the general population: the population that consumes it sporadically. Significantly high values ​​of T-Hg in blue crab and mantis shrimp occurred during low salinity conditions in the estuary, suggesting that Hg mainly originates from river runoff during the rainy season. Nevertheless, the biota-sediment accumulation factor (BSAF) was favored in high salinity, which could mean greater availability of Hg for higher levels of the estuarine food web in the dry season and in marine waters. In general, the T-Hg levels in some samples exceeded 0.2 g·g-1. Therefore this pollutant must be monitored due to its biomagnification potential and as a threat to human health, especially that for the local population of fishermen and their families.


Assuntos
Mercúrio , Animais , Baías , Braquiúros/química , Braquiúros/metabolismo , Criança , Colômbia , Monitoramento Ambiental , Estuários/estatística & dados numéricos , Feminino , Cadeia Alimentar , Humanos , Mercúrio/análise , Mercúrio/química , Gravidez , Rios
16.
Appl Biochem Biotechnol ; 190(3): 1074-1091, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31673937

RESUMO

Chitin is the second-most abundant bioresource and widely used in the food, agricultural, biomedicine, and other industries. However, under the mutual restriction of extraction cost and environmental protection, it is relatively difficult to prepare chitin from natural sources by pure separation. The aim of this study is to extract chitin from fresh crab shell waste by decalcification (DC) and deproteinization (DP) using glutamic acid and alkaline protease. The optimum technological conditions for DC and DP were as follows: (1) 5% (w/v) glutamic acid solution was used as decalcifying agent, the ratio of material to liquid was 1:10 (m/v), and the ash content in chitin was 0.83 ± 0.027% after decalcification at 75° C for 12 h. (2) Using alkaline protease as enzymatic hydrolyzer, 1500 U of alkaline protease was added per gram of crab shell. Under the conditions of material-liquid ratio of 1:10 (m/v) and pH value of hydrolysate of 9.0, N content in chitin was 6.63 ± 0.10% after 6 h of enzymatic hydrolysis at 55° C. And the extraction rate of chitin was 92.25 ± 0.51%. As a decalcifying agent, glutamic acid could be recycled with a recovery rate of 77.42 ± 2.16%. Calcium carbonate in crab shell was converted into calcium hydrogen phosphate by calcium glutamate, and protein into amino acids and polypeptides, which could be used as feed additives. The "glutamic acid-enzymolysis" for extracting chitin from crab shell is a relatively closed process, which has the advantages of mild reaction, greatly reducing the discharge of three wastes and high comprehensive utilization rate of raw materials.


Assuntos
Proteínas de Bactérias/metabolismo , Braquiúros/química , Quitina/isolamento & purificação , Endopeptidases/metabolismo , Ácido Glutâmico/metabolismo , Animais , Cálcio/metabolismo , Quitina/metabolismo , Concentração de Íons de Hidrogênio , Proteólise , Temperatura
17.
Food Chem ; 308: 125607, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31677599

RESUMO

Lipid sources as alternatives to fish oil could alter the nutritional value and flavor quality of crab meat affecting consumer preferences. Herein, an 8-week nutritional trial was designed to investigate the effects of dietary lipid sources including fish oil (FO), krill oil (KO), palm oil, rapeseed oil, soybean oil and linseed oil on profiles of amino acids, fatty acids and volatiles in muscle of swimming crab (Portunus trituberculatus). Volatiles of crab muscle were characterized by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry. Results revealed that crabs fed FO and KO had significantly higher levels of protein, indispensable amino acids, eicosapentaenoic acid and docosahexaenoic acid in muscle. Principal component analysis and hierarchical cluster analysis demonstrated that muscle volatiles of crabs fed different dietary oils exhibited significant variations. Dietary FO and KO significantly increased the relative levels of 3-methylbutanal, heptanal, benzaldehyde and nonanal in muscle, which may produce more pleasant flavors.


Assuntos
Braquiúros/química , Aromatizantes/análise , Animais , Gorduras na Dieta/análise , Ácidos Docosa-Hexaenoicos/análise , Ácido Eicosapentaenoico/análogos & derivados , Ácido Eicosapentaenoico/análise , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Estado Nutricional , Valor Nutritivo , Alimentos Marinhos/análise , Microextração em Fase Sólida , Natação , Paladar
18.
Food Chem ; 302: 125334, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31419773

RESUMO

Carotenoids, natural pigments, are a group of chemically heterogeneous molecules, present in numerous taxonomical clusters. Because of their various bioactivities, carotenoids are day-by-day applied in numerous fields. The present work aimed to investigate an efficient extraction process of carotenoids from blue crab shells and their identification by HR-ESI-MS technique. In this context, different methods (enzymatic, maceration, Soxhlet, etc.) and solvents (variable polarity index) were tested. Maceration using the binary system hexane/isopropanol (50/50) was found to be the most efficient process, producing high carotenoids content and low total phenolic and soluble protein amounts (p < 0.05). When combined with an enzymatic pretreatment, this procedure was found to be remarkably (p < 0.05) more efficient and selective especially towards astaxanthin (p < 0.05). The HR-ESI-MS identified 23 compounds, depending on the adopted extraction approach. The compounds identified may have potential for applications in food or pharmaceutical industries.


Assuntos
Exoesqueleto/química , Braquiúros/química , Carotenoides/isolamento & purificação , Fracionamento Químico/métodos , 2-Propanol/química , Animais , Carotenoides/análise , Hexanos/química , Fenóis/análise , Fenóis/química , Proteínas/análise , Proteínas/isolamento & purificação , Solventes/química , Espectrometria de Massas por Ionização por Electrospray , Espectroscopia de Infravermelho com Transformada de Fourier , Xantofilas/análise , Xantofilas/isolamento & purificação
19.
Int J Biol Macromol ; 142: 705-711, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622722

RESUMO

Secreted phospholipases A2 (sPLA2) are water-soluble lipolytic enzymes that act at the interface of organized lipid substrates, where the catalytic step is coupled to various interfacial phenomena as enzyme penetration, solubilisation of reaction products, lateral packing and loss of mechanical stability of organized assemblies of phospholipid molecule, among others. Using the monomolecular film technique, we compared the interfacial properties of crab digestive sPLA2 (CDPL) with those of the porcine pancreatic one (PPPL). A kinetic study on the surface pressure dependency of the two sPLA2 was performed using monomolecular films of three different substrates: di C12-PC (1.2-dilauroyl-sn-glycerol-3-phosphocholine); di C12-PG (1.2-dilauroyl-sn-glycerol-3-phosphoglycerol) and di C12-PE (1.2-dilauroyl-sn-glycerol-3-phosphoethanolamine). The use of a substrate in monolayer state, during the catalytic reactions, allows us to monitor the effect of several physicochemical parameters by altering the "quality of interface". The effect of temperature on the hydrolysis rate of these substrates was also checked. Our results show that activities of both phospholipases were affected by the variation of the subphase temperature. CDPL was irreversibly inactivated by p-bromo-phenacyl bromide, the specific inhibitor of sPLA2. The hyperbolic catalytic behaviour observed was coherent with hopping mode of action, one of the two characteristic mechanisms of interfacial catalysis of sPLA2.


Assuntos
Braquiúros/química , Lipídeos de Membrana/química , Fosfolipases/química , Fosfolipases/metabolismo , Fosfolipídeos/química , Animais , Catálise , Digestão , Hidrólise , Cinética , Transição de Fase , Fosfolipases A2 Secretórias/química , Fosfolipases A2 Secretórias/metabolismo , Propriedades de Superfície , Suínos , Temperatura de Transição
20.
Int J Biol Macromol ; 147: 931-936, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31739062

RESUMO

The effect of NaOH/urea solution freeze-thaw pretreatment to the chitosan of purity and the degree of deacetylation from the crab shell was examined. Higher purity chitosan (CS1) was prepared. On this basis, the raw materials after the first demineralization were pretreated with NaOH/urea solution freeze-thaw under different freeze-thaw situations. The produced chitosans (CS1-CS4) were characterized in the ash content, solubility, protein content, degree of deacetylation, viscosity average molecular weight, SEM, FTIR, XRD, antimicrobial activity. The results showed that the freeze-thaw process had advantageous influence on decreasing the ash content and increasing degree of deacetylation and antibacterial activity. Moreover, the antibacterial property of the extracted chitosans seemed to be positively related to their degree of deacetylation. It is concluded that CS4 had the lowest ash content (0.052%), the highest degree of deacetylation (86.02%) and the greatest antibacterial activity. Therefore, we recommend CS4 as agent for industrial and pharmaceutical applications.


Assuntos
Braquiúros/química , Quitosana , Hidróxido de Sódio/química , Ureia/química , Animais , Quitosana/química , Quitosana/isolamento & purificação , Congelamento
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