Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Genomics ; 112(1): 736-748, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31095997

RESUMO

Shewanella baltica 128 is a specific spoilage organism (SSO) isolated from the refrigerated shrimp that results in shrimp spoilage. This study reported the complete genome sequencing of this strain, with the primary annotations associated with amino acid transport and metabolism (8.66%), indicating that S. baltica 128 has good potential for degrading proteins. In vitro experiments revealed Shewanella baltica 128 could adapt to the stress conditions by regulating its growth and biofilm formation. Genes that related to the spoilage-related metabolic pathways, including trimethylamine metabolism (torT), sulfur metabolism (cysM), putrescine metabolism (speC), biofilm formation (rpoS) and serine protease production (degS), were identified. Genes (LuxS, pfs, LuxR and qseC) that related to the specific QS system were also identified. Complete genome sequence of S. baltica 128 provide insights into the QS-related spoilage potential, which might provide novel information for the development of new approaches for spoilage detection and prevention based on QS target.

2.
J Food Biochem ; 43(2): e12730, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31353647

RESUMO

Methodology to enhance the intestinal absorption of peptides is an important challenge due to their easily degradation and poor permeability across the intestinal epithelium. In this study, the fish-derived peptide (DGDDGEAGKIG)-loaded chitosan (CS) nanoparticles (CS/PEP-NPs) were prepared and investigated in Caco-2 monolayer model. The results indicated zeta potential of CS/PEP-NPs increased with the increase in molecular weight of CS (10-50 kDa). Transmission electron microscopy images revealed the CS/PEP-NPs were uniform spherical-shaped nanoparticles with a diameter of 50-200 nm (150 kDa). Compared to other CS/PEP-NPs, 150-kDa CS/PEP-NPs performed an outstanding apparent permeability coefficient (Papp, 2.29 × 10-5  cm s-1 ) and cumulative amount of peptide (120 min, 2,987 ng) in Caco-2 cells. CS/PEP-NPs could reduce the tight junction integrity of Caco-2 cells and enhance the intracellular fluorescence intensities of fluorescein isothiocyanate-labeled peptide. These findings suggest that chitosan nanoparticles are promising carriers to promote intestinal absorption of fish-derived peptide via paracellular pathway mediated by tight junctions. PRACTICAL APPLICATIONS: Chitosans are promising carriers to promote intestinal absorption of fish-derived peptide. The 150-kDa CS/PEP-NPs performed an outstanding apparent permeability coefficient (Papp, 2.29 × 10-5  cm s-1 ) and cumulative amount of peptide (120 min, 2,987 ng) in Caco-2 cells. CS/PEP-NPs could reduce the tight junction integrity of Caco-2 cells and enhance the peptide uptake by paracellular pathway. Chitosan nanoparticles can be developed as vehicles for enhancing the cellular uptake of peptide in food industry.

3.
J Food Sci Technol ; 56(5): 2605-2610, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31168142

RESUMO

3-Phenyllactic acid (PLA) is a novel and natural antimicrobial compound. However, the concentration of PLA produced by native microbes was rather low. To enhance the production of PLA of Lactobacillus plantarum AB-1, the microcapsules of L. plantarum AB-1 cells with a high quorum-sensing capacity was established and investigated. In addition, the relation between PLA production and quorum sensing was further investigated and confirmed by adding the exogenous 4,5-dihydroxy-2,3-pentanedione (DPD, AI-2 precursor). The results indicated that the PLA production of L. plantarum AB-1 in microencapsulated cells (MC cells) was higher than that of the free cells, and the lactate dehydrogenase activity, autoinducer-2 (AI-2) levels and the relative expression of the luxS gene were also significantly increased in MC cells (P < 0.05). In addition, the cell growth, AI-2 levels and PLA production of L. plantarum AB-1 were also significantly promoted after adding 24 µM exogenous DPD. The results suggest that the PLA production of L. plantarum was partly regulated by the AI-2/LuxS system, and microencapsulation can increase the local AI-2 level and enhance QS capacity, which are beneficial to PLA production. The results may provide a new insight and experimental basis for the industrial production of PLA.

4.
Food Res Int ; 120: 679-687, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31000286

RESUMO

Litopenaeus vannamei is an extremely perishable food because of rapid microbial growth and chemical degradation after harvesting. Biopreservation is a food preservation technology based on the addition of "positive" bacteria to kill or prevent the growth of undesirable microorganisms. In this study, the cooperation between lactic acid bacteria (LAB) strains (Lactobacillus plantarum AB-1 and Lactobacillus casei) regulated by the AI-2/LuxS was investigated in vitro and on shrimp. The antimicrobial activity of L. plantarum AB-1 was significantly increased in the co-culture compared with the mono-culture in vitro, and the transcription of the quorum sensing luxS gene and bacteriocin regulatory operons (plnB and plnC) in L. plantarum AB-1 were also significantly increased in co-culture (P < .05), indicating cooperation and that the production of bacteriocin in L. plantarum AB-1 might be related to the LuxS/AI-2 quorum sensing (QS) system. The results were confirmed by adding the exogenous AI-2 molecule signal to L. plantarum AB-1 in vitro. In the on shrimp experiments, the spoilage organisms (mainly Shewanella baltica) in shrimp samples were significantly inhibited after co-inoculation with L. plantarum AB-1 and L. casei, and the values of total volatile basic nitrogen (TVB-N) and pH in co-inoculated shrimp were also significantly decreased (P < .05). In addition, the AI-2 activities in co-inoculated shrimp were significantly higher during refrigerated storage. The results suggest that the cooperation and bacteriocin production of lactic acid bacteria might by regulated by the AI-2/LuxS system, and the co-inoculation of L. plantarum AB-1 and L. casei in shrimp is an effective strategy for biopreservation of shrimp.

5.
J Food Sci Technol ; 56(1): 114-121, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30728552

RESUMO

Shewanella baltica is the predominant bacteria in spoiled shrimp (Litopenaeus vannamei), however, the spoilage ability and the mechanism of S. baltica is still unknown. S. baltica can't produce the signal molecule of acyl-homoserine-lactones (AHLs), so the aim of this study was to investigate how wild type S. baltica SA03 (WT SA03) eavesdrop exogenous AHLs to enhance its spoilage ability through LuxR receptor. The results indicated that Aeromonas spp. (Aer), Acinetobacter spp. (Aci) and Serratia spp. (Ser) isolated from refrigerated shrimp can produce different AHLs. WT SA03 can eavesdrop the AHLs of Aer (C4-HSL), Aci (O-C6-HSL) and Ser (C6-HSL, O-C6-HSL) to enhance its growth, especially Ser. Exogenous C4-HSL and C6-HSL enhanced biofilm formation of WT SA03, and C6-HSL and O-C6-HSL enhanced thioredoxin reductase trxB mRNA expression. However, the luxR mutant of WT SA03 (ΔluxR SA03) lost or weakened the role of using environmental AHLs. In vivo experiments, the lag time of WT SA03 was shortened by 6.4 h, 6.2 h and 14.4 h by co-inoculated with Aer, Aci and Ser, respectively. The total volatile basic nitrogen (TVB-N) were significantly enhanced in the samples co-inoculated with WT SA03 and Aer (or Aci, Ser) than those of ΔluxR SA03 and Aer (or Aci, Ser) (p < 0.05). The results showed that S. baltica SA03 can utilize AHLs produced by other bacteria to enhance its growth and spoilage ability through LuxR receptor system. Quorum sensing based on AHLs of bacteria might as the potential targets for food spoilage control.

6.
Mar Drugs ; 16(10)2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30308963

RESUMO

In this paper, a novel natural influenza A H1N1 virus neuraminidase (NA) inhibitory peptide derived from cod skin hydrolysates was purified and its antiviral mechanism was explored. From the hydrolysates, novel efficient NA-inhibitory peptides were purified by a sequential approach utilizing an ultrafiltration membrane (5000 Da), sephadex G-15 gel column and reverse-phase high-performance liquid chromatography (RP-HPLC). The amino acid sequence of the pure peptide was determined by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was PGEKGPSGEAGTAGPPGTPGPQGL, with a molecular weight of 2163 Da. The analysis of the Lineweacer⁻Burk model indicated that the peptide was a competitive NA inhibitor with Ki of 0.29 mM and could directly bind free enzymes. In addition, docking studies suggested that hydrogen binding might be the driving force for the binding affinity of PGEKGPSGEAGTAGPPGTPGPQGL to NA. The cytopathic effect reduction assay showed that the peptide PGEKGPSGEAGTAGPPGTPGPQGL protected Madin⁻Darby canine kidney (MDCK) cells from viral infection and reduced the viral production in a dose-dependent manner. The EC50 value was 471 ± 12 µg/mL against H1N1. Time-course analysis showed that PGEKGPSGEAGTAGPPGTPGPQGL inhibited influenza virus in the early stage of the infectious cycle. The virus titers assay indicated that the NA-inhibitory peptide PGEKGPSGEAGTAGPPGTPGPQGL could directly affect the virus toxicity and adsorption by host cells, further proving that the peptide had an anti-viral effect with multiple target sites. The activity of NA-inhibitory peptide was almost inactivated during the simulated in vitro gastrointestinal digestion, suggesting that oral administration is not recommended. The peptide PGEKGPSGEAGTAGPPGTPGPQGL acts as a neuraminidase blocker to inhibit influenza A virus in MDCK cells. Thus, the peptide PGEKGPSGEAGTAGPPGTPGPQGL has potential utility in the treatment of the influenza virus infection.


Assuntos
Antivirais/farmacologia , Gadus morhua/metabolismo , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Neuraminidase/antagonistas & inibidores , Peptídeos/farmacologia , Pele/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Cães , Células Madin Darby de Rim Canino , Peso Molecular , Infecções por Orthomyxoviridae/tratamento farmacológico , Carga Viral/métodos
7.
Mar Drugs ; 16(9)2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30201855

RESUMO

Probiotic-derived polyphosphates have attracted interest as potential therapeutic agents to improve intestinal health. The current study discovered the intracellular accumulation of polyphosphates in a marine cyanobacterium Synechococcus sp. PCC 7002 as nano-sized granules. The maximum accumulation of polyphosphates in Synechococcus sp. PCC 7002 was found at the late logarithmic growth phase when the medium contained 0.74 mM of KH2PO4, 11.76 mM of NaNO3, and 30.42 mM of Na2SO4. Biogenic polyphosphate nanoparticles (BPNPs) were obtained intact from the algae cells by hot water extraction, and were purified to remove the organic impurities by Sephadex G-100 gel filtration. By using 100 kDa ultrafiltration, BPNPs were fractionated into the larger and smaller populations with diameters ranging between 30⁻70 nm and 10⁻30 nm, respectively. 4',6-diamidino-2-phenylindole fluorescence and orthophosphate production revealed that a minor portion of BPNPs (about 14⁻18%) were degraded during simulated gastrointestinal digestion. In vitro studies using lipopolysaccharide-activated RAW264.7 cells showed that BPNPs inhibited cyclooxygenase-2, inducible nitric oxide (NO) synthase expression, and the production of proinflammatory mediators, including NO, tumor necrosis factor-α, interleukin-6, and interleukin-1ß through suppressing the Toll-like receptor 4/NF-κB signaling pathway. Overall, there is promise in the use of the marine cyanobacterium Synechococcus sp. PCC 7002 to produce BPNPs, an anti-inflammatory postbiotic.


Assuntos
Anti-Inflamatórios/farmacologia , Produtos Biológicos/farmacologia , Nanopartículas , Polifosfatos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Synechococcus/metabolismo , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/metabolismo , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/metabolismo , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos/imunologia , Camundongos , Polifosfatos/isolamento & purificação , Polifosfatos/metabolismo , Células RAW 264.7 , Transdução de Sinais/imunologia
8.
Mar Drugs ; 16(8)2018 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-30081563

RESUMO

Natural angiotensin converting enzyme (ACE)-inhibitory peptides, which are derived from marine products, are useful as antihypertensive drugs. Nevertheless, the activities of these natural peptides are relatively low, which limits their applications. The aim of this study was to prepare efficient ACE-inhibitory peptides from sea cucumber-modified hydrolysates by adding exogenous proline according to a facile plastein reaction. When 40% proline (w/w, proline/free amino groups) was added, the modified hydrolysates exhibited higher ACE-inhibitory activity than the original hydrolysates. Among the modified hydrolysates, two novel efficient ACE-inhibitory peptides, which are namely PNVA and PNLG, were purified and identified by a sequential approach combining a sephadex G-15 gel column, reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS), before we conducted confirmatory studies with synthetic peptides. The ACE-inhibitory activity assay showed that PNVA and PNLG exhibited lower IC50 values of 8.18 ± 0.24 and 13.16 ± 0.39 µM than their corresponding truncated analogs (NVA and NLG), respectively. Molecular docking showed that PNVA and PNLG formed a larger number of hydrogen bonds with ACE than NVA and NLG, while the proline at the N-terminal of peptides can affect the orientation of the binding site of ACE. The method developed in this study may potentially be applied to prepare efficient ACE-inhibitory peptides, which may play a key role in hypertension management.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Peptídeos/farmacologia , Peptidil Dipeptidase A/metabolismo , Hidrolisados de Proteína/química , Pepinos-do-Mar , Inibidores da Enzima Conversora de Angiotensina/química , Inibidores da Enzima Conversora de Angiotensina/isolamento & purificação , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Animais , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Desenho de Drogas , Ensaios Enzimáticos , Hipertensão/tratamento farmacológico , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Peptídeos/química , Peptídeos/isolamento & purificação , Prolina/química , Hidrolisados de Proteína/farmacologia , Relação Estrutura-Atividade , Especificidade por Substrato , Espectrometria de Massas em Tandem/métodos
9.
J Food Sci Technol ; 55(7): 2795-2800, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30042596

RESUMO

Numerous bacterial species utilize quorum sensing molecules acyl-homoserine-lactones (AHLs) to communicate, however, crosstalk often complicates the dynamics and behaviors of mixed populations. In this study, we developed a luxR mutant of wild type Shewanella baltica SA03 (WT SA03), and aimed to investigate the role of S. baltica LuxR (AHLs receptor) involved in the spoilage of refrigerated shrimp (Litopenaeus vannamei) by inoculating WT SA03 and luxR mutant of S. baltica SA03 (ΔluxR SA03), respectively. The results indicated the maximum growth rate of total viable bacteria in shrimp inoculated with ΔluxR SA03 was 73.34% lower than that of WT SA03. The lag time of total bacteria in shrimp treated with ΔluxR SA03 were 87.6 h, significantly longer than that of WT SA03. Meanwhile, the total volatile basic nitrogen concentrations of shrimp treated with WT SA03 were significantly higher than that of ΔluxR SA03 after 2 days of storage, which were in agreement with the decrease of the content of AHLs of the shrimp. The results indicated S. baltica might utilize AHLs produced by other bacteria and accelerate the shrimp spoilage process through LuxR receptor system.

10.
Food Funct ; 9(8): 4135-4142, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30019729

RESUMO

In this study, with grass fish bones as the substrate, after flavourzyme treatment, and fermentation with Leuconostoc mesenteroides, a fermentation solution with a high content of soluble calcium was obtained. High performance liquid chromatography and GC-MS analysis indicated that free calcium (11.29 mmol L-1) in the fermentation solution was composed of calcium lactate (3.89 mmol L-1), calcium acetate (6.21 mmol L-1), calcium amino acids and small peptide calcium. Animal experiments show that the fermentation solution of grass fish bones could promote the growth and development of calcium-deficient rats. Complex organic calcium could be well absorbed and utilized by rats so that serum calcium, alkaline phosphatase levels, femur weight and other indicators in calcium-deficient rats could be returned to normal levels. The fermentation solution of grass fish bones can avoid the waste of aquatic proteins and fish bone calcium, and it exhibited high calcium bioavailability. Therefore, the fermentation solution of grass fish bones might be used as a new efficient calcium supplement.


Assuntos
Osso e Ossos/química , Cálcio/farmacocinética , Carpas , Fosfatase Alcalina , Ração Animal/análise , Animais , Densidade Óssea , Cálcio/administração & dosagem , Cálcio/sangue , Cálcio/química , Dieta/veterinária , Fermentação , Manipulação de Alimentos , Leuconostoc mesenteroides/fisiologia , Masculino , Fósforo/sangue , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
11.
J Food Sci Technol ; 55(5): 1903-1912, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29666543

RESUMO

Shewanella baltica and Acinetobacter are among the predominant spoilage bacteria in refrigerated shrimp (Litopenaeus vannamei). S. baltica are incapable of producing acyl-homoserine lactone (AHL) quorum sensing signals, but can respond to environmental AHLs. In this paper, Acinetobacter was found to produce three AHLs, i.e. N-butanoyl-l-homoserine lactone (C4-HSL), N-(3-oxohexanoyl)-l-homoserine lactone (O-C6-HSL) and N-(3-oxooctanoyl)-l-homoserine lactone (O-C8-HSL), according to thin-layer chromatography using the bioreporter Agrobacterium tumefaciens A136. The agar diffusion and ß-galactosidase assays revealed that S. baltica could eavesdrop on these three AHLs from Acinetobacter. Eavesdropping on Acinetobacter AHLs especially C4-HSL was found to boost the growth of S. baltica particularly under nutrient limiting conditions (up to 40-fold increase) in the co-culture experiments. The azocasein assay revealed that S. baltica produced fourfold more extracellular proteases in response to Acinetobacter AHLs. As demonstrated by the biofilm crystal violet staining assay and confocal laser scanning microscopy, eavesdropping also decreased the biofilm-forming capacity of Acinetobacter. By inoculation of S. baltica and Acinetobacter onto surface-sterilized shrimp, eavesdropping was found to endow a growth advantage to S. baltica in vivo, resulting in a 0.5 day shortened shelf life of shrimp according to total volatile basic nitrogen levels and sensory analysis. Overall, the AHL-dependent eavesdropping increased the spoilage potential of S. baltica, providing a fresh perspective on the spoilage process of refrigerated L. vannamei, and this may inspire the development of novel preservation techniques in the future to further reduce post-harvest loss of shrimp.

12.
Eur J Pharmacol ; 818: 184-190, 2018 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-29080788

RESUMO

l-Theanine (LTA; γ-glutamylethylamide), a peculiar non-protein-derived amino acid isolated from tea, is widely used as a functional ingredient and dietary supplement. l-Theanine has been confirmed to have hepatoprotective effects, but the underlying mechanism remains unknown. This study investigated the protective effect of l-Theanine-in vivo, using an enterotoxigenic Escherichia coli (ETEC)-infected mouse model. l-Theanine significantly decreased the elevated serum activities of both aspartate aminotransferase (AST) and alanine aminotransferase (ALT), two biomarkers of hepatic impairment. This was consistent with histopathological images from the microscopic observation of liver tissue. In addition, l-theanine significantly increased the mRNA and protein expression of Bcl-2 and decreased the expression of Bax, anti- and pro-apoptotic molecules, respectively, compared with levels in the ETEC control group. The expression of cleaved caspase-3 protein in the group pre-treated with l-theanine was significantly lower than that in the ETEC group. Additionally, decreases in extracellular signal-regulated kinase (ERK1/2) and c-Jun NH2-terminal kinase(JNK1/2) MAPK phosphorylation were observed in the l-theanine pre-treated group. Our study demonstrates that l-theanine possesses anti-apoptotic activity, which can be attributed to suppression of the intrinsic mitochondria-mediated apoptosis and MAPK phosphorylation signaling pathways.


Assuntos
Apoptose/efeitos dos fármacos , Escherichia coli Enterotoxigênica/fisiologia , Glutamatos/farmacologia , Fígado/efeitos dos fármacos , Fígado/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Animais , Feminino , Regulação Enzimológica da Expressão Gênica , Fígado/microbiologia , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
13.
J Food Sci Technol ; 54(7): 1809-1817, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28720936

RESUMO

The objective of the present study was to investigate the effects of superchilling with modified atmosphere packaging on the physicochemical properties and shelf life of swimming crab. As the storage time increased, the rates at which the total aerobic plate count, total volatile basic nitrogen, pH, peroxide value and thiobarbituric acid-reactive substances value increase were significantly lower for the superchilling with modified atmosphere packaging (SCS + MAP) treatment compared to superchilling storage (SCS) and chilling storage (CS). With increasing storage time, the carbonyl content of the proteins increased from 1.21 nmol/mg of protein (0 day) to 2.03, 1.87, 1.66 nmol carbonyl/mg protein on the 6th day for CS, SCS and SCS + MAP, respectively. The disulfide bonds increased in a similar manner, and the total sulfhydryl content, salt extractable protein and Ca-ATPase stability decreased. Sodium dodecyl sulphate polyacrylamide gel elcetrophoresis (SDS-PAGE) and microstructure analysis also indicated that SCS + MAP could reduce the degree of protein degradation. These results suggested that superchilling with modified atmosphere packaging offers an effective approach to slowdown protein and lipid oxidation, and extends the shelf life of swimming crab. However, superchilling with high-CO2 packaging had a negative effect on the surface hydrophobicity and drip loss of swimming crab.

14.
Food Funct ; 7(11): 4709-4719, 2016 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-27805212

RESUMO

The aim of this research was to investigate the accumulation and excretion of AGEs including fluorescent compounds and N-ε-carboxymethyllysine (CML) in streptozotocin-induced diabetes C57BL/6J mice fed on a diet containing Maillard reaction products (MRPs) from a silver carp peptide-glucose model system at different heating temperatures for the first time, and analyze the relationship between their in vitro antioxidant activity based on DPPH and ORAC assays and in vivo oxidative stress. The in vitro antioxidant activity of MRPs positively correlated with their AGEs level and molecular weight distribution. However, the opposite results were found by malondialdehyde (MDA) and super oxide dismutase (SOD) assays that MRPs from a higher heating temperature could aggravate the oxidative stress of diabetic mice. CML accumulation in serum was aggravated, but changes of MRPs in diets hardly affected CML accumulation in the kidney and liver. Therefore, the high AGEs levels from a diet containing peptide MRPs have negative effects on the oxidative stress of diabetic mice.


Assuntos
Antioxidantes/metabolismo , Produtos Finais de Glicação Avançada/química , Carne/análise , Peptídeos/química , Animais , Peso Corporal , Carpas , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Intolerância à Glucose , Rim , Fígado , Reação de Maillard , Estresse Oxidativo
15.
J Food Sci Technol ; 52(8): 4841-51, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26243904

RESUMO

Three freezing-point regulators (glycine, sodium chloride and D-sorbitol) were employed to optimize thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) using response surface methodology (RSM). The independent variables were glycine content (0.250-1.250 %), sodium chloride content (0.500-2.500 %) and D-sorbitol content (0.125-0.625 %) and analysis of variance showed that the effects of glycine, sodium chloride and D-sorbitol on the thermophysical properties were statistically significant (P < 0.05). The coefficient of determination, R (2) values for initial freezing point (T i ), unfreezable water mass fraction (W u ), apparent specific heat (C app ) and Enthalpy (H) were 0.896 ~ 0.999. The combined effects of these independent variables on T i , W u , C app and H were investigated. The results indicated that T i , C app and H varied curvilinearly with increasing of glycine, sodium chloride and D-sorbitol content whereas W u increased nearly linearly. Based on response plots and desirability functions, the optimum combination of process variables for Pacific white shrimp previously treated with freezing-point regulators were 0.876 % for glycine content, 2.298 % for sodium chloride content and 0.589 % for D-sorbitol content, correspondently the optimized thermophysical properties were T i , - 5.086 °C; W u , 17.222 %; C app , 41.038 J/g °C and H, 155.942 J/g, respectively. Briefly, the application of freezing-point regulators depressed T i and obtained the optimum W u , C app and H, which would be obviously beneficial for the exploitation of various thermal processing and food storage.

16.
Food Funct ; 6(6): 1919-27, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25965854

RESUMO

Recently, much attention has been given to improving the antioxidant activity of protein hydrolysates via the Maillard reaction, but little is known about the cellular antioxidant activity of Maillard reaction products (MRPs) from protein hydrolysates. We first investigated chemical characterization and the cellular antioxidant activity of MRPs in a shrimp (Litopenaeus vannamei) by-product protein hydrolysate (SBH)-glucose system at 110 °C for up to 10 h of heating. Solutions of SBH and glucose were also heated alone as controls. The Maillard reaction greatly resulted in the increase of hydroxymethylfurfural (HMF) and browning intensity, high molecular weight fraction, and reduction of the total amino acid in SBH with the heating time, which correlated well with the free radical scavenging activity of MRPs. MRPs had stronger inhibiting effects on oxidative stress of human HepG2 cells than the original SBH, and its cellular antioxidant activity strongly correlated with free radical scavenging activity, but less affected by the browning intensity and HMF level. The caramelization of glucose partially affected the HMF level and free radical scavenging activity of MRPs, but it was not related to the cellular antioxidant activity. The cellular antioxidant activity of MRPs for 5 h of heating time appeared to reach a maximum level, which was mainly due to carbonyl ammonia condensation reaction. In conclusion, the Maillard reaction is a potential method to increase the cellular antioxidant activity of a shrimp by-product protein hydrolysate, but the higher HMF levels and the lower amino acid content in MRPs should also be considered.


Assuntos
Antioxidantes/química , Proteínas de Artrópodes/química , Hepatócitos/metabolismo , Estresse Oxidativo , Penaeidae/química , Hidrolisados de Proteína/química , Espécies Reativas de Oxigênio/antagonistas & inibidores , Animais , Antioxidantes/economia , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Proteínas de Artrópodes/economia , Proteínas de Artrópodes/isolamento & purificação , Proteínas de Artrópodes/metabolismo , Sobrevivência Celular , China , Proteínas na Dieta/química , Proteínas na Dieta/economia , Proteínas na Dieta/isolamento & purificação , Proteínas na Dieta/metabolismo , Suplementos Nutricionais/análise , Suplementos Nutricionais/economia , Conservantes de Alimentos/química , Conservantes de Alimentos/economia , Conservantes de Alimentos/isolamento & purificação , Conservantes de Alimentos/metabolismo , Indústria de Processamento de Alimentos/economia , Furaldeído/análogos & derivados , Furaldeído/análise , Furaldeído/química , Glucose/química , Células Hep G2 , Temperatura Alta , Humanos , Resíduos Industriais/análise , Resíduos Industriais/economia , Reação de Maillard , Peso Molecular , Hidrolisados de Proteína/economia , Espécies Reativas de Oxigênio/metabolismo
17.
Int J Food Microbiol ; 192: 26-33, 2015 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-25305441

RESUMO

Quorum-sensing signals in refrigerated shrimp (Litopenaeus vannamei) undergoing spoilage were examined using bioreporter assays, thin-layer chromatography and gas chromatography-mass spectrometry, and the results revealed the presence of three types of autoinducers including acetylated homoserine lactones (AHLs) (i.e., N-hexanoyl-homoserine lactone, N-oxohexanoyl-homoserine lactone and N-octanoyl-homoserine lactone), autoinducer-2, and cyclic dipeptides (i.e., cyclo-(L-Pro-L-Leu), cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe)). Autoinducer-2, rather than any AHL, was detected in extracts from pure cultures of the specific spoilage organisms (SSO), i.e., Shewanella putrefaciens (SS01) and Shewanella baltica (SA02). As for the cyclic peptides, only SA02 was determined to produce cyclo-(L-Pro-L-Leu). According to the transcription levels of LuxR (the master quorum-sensing regulator) in the SSO in response to exogenous autoinducers, the SSO could sense AHLs and cyclo-(L-Leu-L-Leu), rather than autoinducer-2, cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe). In accordance with the results of LuxR expression, the production of biofilm matrixes and extracellular proteases in the SSO was regulated by exogenous AHLs and cyclo-(L-Pro-L-Leu), rather than 4,5-dihydroxy-2,3-pentanedione (the autoinducer-2 precursor), cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe). Exogenous N-hexanoyl-homoserine lactone and cyclo-(L-Pro-L-Leu) increased the growth rates and population percentages of the SSO in shrimp samples under refrigerated storage, and interestingly, exogenous 4,5-dihydroxy-2,3-pentanedione also increased the population percentages of the SSO in vivo by inhibiting the growth of the competing bacteria. However, according to the levels of TVB-N and the volatile organic components in the shrimp samples, exogenous 4,5-dihydroxy-2,3-pentanedione did not accelerate the shrimp spoilage process as N-hexanoyl-homoserine lactone and cyclo-(L-Pro-L-Leu) did. In summary, our results suggest that quorum sensing involves the spoilage of refrigerated Litopenaeus vannamei.


Assuntos
Temperatura Baixa , Microbiologia de Alimentos , Lactonas/metabolismo , Penaeidae/microbiologia , Percepção de Quorum , Shewanella/crescimento & desenvolvimento , Shewanella/metabolismo , Animais , Cromatografia em Camada Delgada , Cromatografia Gasosa-Espectrometria de Massas , Lactonas/análise
18.
J Agric Food Chem ; 62(34): 8632-9, 2014 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-25074419

RESUMO

The mechanisms by which meat enhances human absorption of non-heme iron remain unknown. Recently, anchovy (Engraulis japonicus) muscle protein hydrolysate (AMPH) was found to mediate the formation of nanosized ferric hydrolysis products in vitro. The current paper evaluates the effects of AMPH on the bioavailability and the intestinal speciation of non-heme iron in rats, followed by an investigation of cellular uptake pathways of in vitro-formed AMPH-stabilized nanosized ferric hydrolysis products (ANPs) by polarized human intestinal epithelial (Caco-2) cells. The hemoglobin regeneration efficiencies in anemic rats followed the order ferric citrate (9.79 ± 2.02%) < commercial bare α-Fe2O3 nanoparticles (16.37 ± 6.65%) < mixture of ferric citrate and AMPH (40.33 ± 6.36%) ≈ ferrous sulfate (40.88 ± 7.67%) < ANPs (56.25 ± 11.35%). Percentage contents of intestinal low-molecular-weight iron in the groups of FC+AMPH, FeSO4, and ANPs were significantly lower than the corresponding hemoglobin regeneration efficiencies (P < 0.05), providing strong evidence for the involvement of nanosized iron in intestinal iron absorption from FC+AMPH, FeSO4, and ANPs. Calcein-fluorescence measurements of the labile iron pool of polarized Caco-2 cells revealed the involvement of both divalent transporter 1 and endocytosis in apical uptake of ANPs, with endocytosis dominating at acidic extracellular pH. Overall, AMPH enhancement of non-heme iron absorption involves a nanoparticle-mediated mechanism.


Assuntos
Anemia/metabolismo , Proteínas de Peixes/metabolismo , Absorção Intestinal , Mucosa Intestinal/metabolismo , Ferro/metabolismo , Alimentos Marinhos/análise , Anemia/dietoterapia , Anemia/fisiopatologia , Animais , Disponibilidade Biológica , Células CACO-2 , Feminino , Proteínas de Peixes/química , Peixes , Humanos , Hidrólise , Intestinos/fisiopatologia , Ferro/química , Masculino , Nanopartículas/química , Nanopartículas/metabolismo , Ratos
19.
J Agric Food Chem ; 61(1): 219-24, 2013 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-23244619

RESUMO

Nanosized iron fortificants appear to be promising and can be synthesized in a greener way using peptides as biotemplates. Anchovy is a huge underdeveloped source of muscle protein that enhances human nonheme iron absorption. This paper shows that peptides in anchovy ( Engraulis japonicus ) muscle protein hydrolysate (AMPH) mediate the formation of monodispersed ferric oxyhydroxide nanoparticles (FeONPs) with diameters of 20-40 nm above pH 3.0. Peptides in AMPH nucleate iron through carboxyl groups and crystal growth then occur as a result of condensation of carboxylate-ligated hydroxide iron centers, yielding Fe-O-Fe cross-link bonds. Monomers of FeONPs are formed after steric obstruction of further crystal growth by peptide backbones with certain lengths and further stabilized by surface-adsorbed peptides. The iron-loading capacity of peptides in AMPH is up to 27.5 mg iron/g peptide. Overall, the present study provides a greener alternative route to the synthesis of FeONPs.


Assuntos
Compostos Férricos/química , Peixes/metabolismo , Nanopartículas Metálicas , Proteínas Musculares/metabolismo , Peptídeos/química , Animais , Humanos , Microscopia Eletrônica de Transmissão , Proteínas Musculares/química , Proteólise
20.
J Agric Food Chem ; 58(2): 1270-4, 2010 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-20085374

RESUMO

Pepsin-solubilized collagen (PSC) was extracted from giant red sea cucumbers ( Parastichopus californicus ) and characterized for denaturation temperature (T(d)), maximum transition temperature (T(m)), enzyme-digested peptide maps, and gel-forming capability. SDS-PAGE showed that PSCs from giant red sea cucumber skin and connective tissue were both type I collagens, consisting of three alpha(1) chains of approximately 138 kDa each. The amino acid composition and peptide maps of PSCs digested by V8 protease were different from those of calf skin type I collagen. The T(d) and T(m) are 18.5 and 33.2 degrees C, respectively, for skin PSC and are 17.9 and 32.7 degrees C, respectively, for connective tissue PSC. Both skin and connective tissue PSCs exhibited good gel-forming capability at pH 6.5 and at an ionic strength of 300 mM salt (NaCl). Collagen isolated from giant red sea cucumbers might be used as an alternative to mammalian collagen in the food and pharmaceutical industries.


Assuntos
Colágeno/química , Colágeno/isolamento & purificação , Tecido Conjuntivo/química , Pepinos-do-Mar/química , Pele/química , Aminoácidos/análise , Animais , Tecido Conjuntivo/metabolismo , Concentração de Íons de Hidrogênio , Pepsina A/química , Pepinos-do-Mar/metabolismo , Pele/metabolismo , Solubilidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA