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1.
Food Chem ; 372: 131235, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34624781

RESUMO

In this study, a new surface-enhanced Raman scattering (SERS)-based method has been developed for the detection of plasmin activity. Firstly, different peptide sequences, which are specific to plasmin, were examined. Then, SERS substrates were prepared by chosen peptide substrate. Enzyme activity was determined by pursuing the reduction of DTNB band at 1331 cm-1 with Raman spectroscopy. The reduction in SERS intensity was related to the plasmin activity, and changes in SERS intensity vs. plasmin concentration graph was obtained. Limit of detection (LOD) and limit of quantification (LOQ) values were calculated as 2.14 U/mL and 6.42 U/mL, respectively. Intra- and inter-day repeatability results were determined as 1.45% and 1.47% relative standard deviation (RSD). Also, recovery of the method was determined for the plasmin spiked milk samples. The results demonstrated that the proposed method could be successfully used to detect the plasmin activity in milk samples.


Assuntos
Nanopartículas Metálicas , Análise Espectral Raman , Fibrinolisina , Ouro , Limite de Detecção , Peptídeos
2.
J Sci Food Agric ; 100(13): 4756-4765, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32458436

RESUMO

BACKGROUND: Heat treatment is the most common practice for the microbiological safety of milk; hence, determination of the heat treatment of milk is essential. Also, mislabeling or adulteration of expensive milk samples, like ewe or goat milk, with cow's milk is a growing problem in the dairy market. Thus, the determination of the authenticity of milk samples has crucial importance for both producers and consumers. The aim of this study was to discriminate milk samples using Raman spectroscopy with partial least squares discriminant analysis (PLS-DA), first with regard to whether the milk was heat-treated or not, and second with regard to species (cow, goat, ewe, mixture (adulterated)) in both raw and pasteurized milk. RESULTS: First, discrimination of milk samples as raw or pasteurized was achieved using PLS-DA. Both in calibration and prediction models, high sensitivity and specificity values were obtained for raw and pasteurized milk samples. Second, the proposed method also discriminated milk samples according to their species (cow, goat, ewe, and mixture) for both raw and pasteurized milk. In both calibration and prediction models, the sensitivity and specificity values were above 0.857 and 0.897 respectively. Also, the accuracy values were above 0.915. The results obtained denote satisfactory accurate classification of the samples. CONCLUSION: The results suggest that Raman spectroscopy coupled with PLS-DA can be successfully used to discriminate milk samples according to heat treatment (raw/pasteurized) and their species within 20 s per sample. It was seen that Raman spectra provide valuable information to be used especially for discrimination of milk samples according to their origin. © 2020 Society of Chemical Industry.


Assuntos
Contaminação de Alimentos/análise , Leite/química , Análise Espectral Raman/métodos , Animais , Bovinos , Análise Discriminante , Feminino , Cabras , Análise dos Mínimos Quadrados , Pasteurização , Ovinos
3.
Acta Odontol Scand ; 78(5): 327-331, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31980002

RESUMO

Objective: Type 2 diabetes mellitus (T2DM) is a well-defined risk factor of periodontitis and it can affect expression of human beta-defensins (hBDs) and cathelicidin (LL-37) as well. The aim of the present study was to evaluate the impact of periodontitis and T2DM on salivary concentrations of these antimicrobial peptides.Material and methods: Unstimulated saliva samples, together with full-mouth periodontal recordings were collected from 92 individuals with periodontitis (63 with T2DM and 21 smokers) and 86 periodontally healthy controls (58 with T2DM and 21 smokers). Salivary hBD-1, -2, -3, LL-37, and advanced glycalization end products (AGE) concentrations were measured by enzyme-linked immunosorbent assay.Results: Among the periodontitis patients, T2DM group demonstrated lower levels of hBD-1 (p = .006), hBD-2 (p < .001) and hBD-3 (p < .001), and higher levels of LL-37 (p < .001) compared to systemically healthy controls. When only periodontally healthy controls were included into the analysis, higher hBD-1 (p = .002) and LL-37 (p < .001) levels were found in T2DM patients in comparison to systemically healthy controls. Salivary LL-37 levels were associated with HbA1c and periodontitis, while hBD-2, hBD-3 and levels associated only with HbA1c.Conclusion: In the limits of this study, hyperglycaemia can be proposed as a regulator of salivary hBD and cathelicidin levels. Periodontitis, on the other hand, affects only salivary LL-37 levels.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Diabetes Mellitus Tipo 2/sangue , Periodontite/sangue , Saliva/química , beta-Defensinas/sangue , Adulto , Peptídeos Catiônicos Antimicrobianos/sangue , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/complicações , Hemoglobinas Glicadas , Humanos , Pessoa de Meia-Idade , Periodontite/microbiologia , Periodontite/terapia , Saliva/metabolismo , beta-Defensinas/metabolismo , Catelicidinas
4.
J Food Sci ; 85(2): 500-509, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31958152

RESUMO

Antibiotics are one of the most widely used types of drugs in pharmaceutics. However, efficiency of these drugs has decreased recently owing to the threat of antibiotic resistance. One of the important factors causing antibiotic resistance is the excessive use of antibacterials in animals. Therefore, detection of antibiotics in foods of animal origin is crucial. The aim of this study was to develop a novel whole-cell based bioassay to be used for detection of some antibiotics. Green fluorescent protein (GFP)-expressing Escherichia coli cells were used as a recognition agent, and antibiotic detection was carried out by pursuing the inhibition rate of fluorescence intensity as a result of the inhibition of viable cells by the time of progress. The performance of bioassay was tested for different antibiotics, and the obtained results showed that the developed method can be used successfully for detection of ampicillin, benzylpenicillin, gentamicin, neomycin, and tetracycline with the limit of detection (LOD) values of 3.33, 0.29, 28.00, 618.36, and 33.17 µg/L, respectively. The assay was also tested with antibiotic spiked milk samples (skimmed UHT, full-fat UHT, and whole raw milk). According to obtained recovery values, developed method was successful for all samples. The precision and bias values of the method were found between the range of 1.30% to 7.54% and -8.00% to 0.64%, respectively. The developed method, which is inexpensive and simple with detection limits in line with the regulatory limits, is promising for use in milk quality monitoring. Method has potential to be used as a screening method after comprehensive validation. PRACTICAL APPLICATION: This method could be used in animal husbandry to check whether the antibiotic prescribed for the treatment of sick animals is still present in their milk as residual. For dairy industry, detection of residual antibiotics in milk is crucial because of their inhibition effects on the fermentation processes. Therefore, the proposed method can be used for routine analysis of raw milk reception in dairy industries. In addition, it is considered to have a wide range of applications for all foods.


Assuntos
Antibacterianos/análise , Bioensaio/métodos , Técnicas Biossensoriais/métodos , Resíduos de Drogas/análise , Leite/química , Ampicilina/análise , Animais , Bovinos , Escherichia coli/genética , Escherichia coli/metabolismo , Fluorescência , Contaminação de Alimentos/análise , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Tetraciclina/análise
5.
J Food Drug Anal ; 27(1): 101-110, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30648563

RESUMO

The adulteration of milk fat in dairy products with cheaper non-milk based fats or oils is frequently encountered in the dairy industry. In this study, Raman spectroscopy with chemometric was used for the discrimination of foreign fats and oils in milk cream and yogurt. Firstly, binary mixtures of cream and oils (corn and sunflower oil), and vegetable fat blends which are potentially or currently used by the dairy industry were prepared. All fat or oil samples and their binary mixtures were examined by using Raman spectroscopy. Then, fat content of skim milk was adjusted to 3% (w/w) by the milk fat, external oils or fats, and binary mixtures, and was used in yogurt production. The lipid fraction of yogurt was extracted and characterized by Raman spectroscopy. The spectral data were then pre-processed and principal component analysis (PCA) was performed. Raman spectral data showed successful discrimination for about the source of the fats or oils. Temperature effect was also studied at six different temperatures (25, 30, 40, 50, 60 and 70 °C) in order to obtain the best spectral information. Raman spectra collected at higher temperatures were more intense. Obtained results showed that the performance of Raman spectroscopy with PCA was very promising and can be expected to provide a simple and quick way for the discrimination of foreign fats and oils in both milk cream and yogurt. Fermentation and yogurt processing affected clustering of fat samples by PCA, probably depending on some lipolysis or production of new products that can affect the Raman scattering. However, those changes did not affect differentiation of samples by Raman spectroscopy.


Assuntos
Manteiga/análise , Gorduras/química , Contaminação de Alimentos/análise , Análise Espectral Raman/métodos , Iogurte/análise , Animais , Bovinos , Leite/química , Óleos de Plantas/química , Análise de Componente Principal
6.
Implant Dent ; 26(4): 581-591, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28639985

RESUMO

OBJECTIVES: The present study aimed at evaluating both the implant site-related and patient-based factors with the potential to affect the extent of patients' satisfaction and also their perceptions regarding dental implant treatment. Potential differences between the esthetic evaluations of dental patients and dental specialists were also considered. MATERIALS AND METHODS: Implant-supported fixed prosthesis (n = 164) in 264 anterior esthetic implant sites were included. Patients' satisfaction, esthetic considerations, and perceptions toward dental implants, were evaluated by both Oral Health Impact Profile-14 (OHIP-14) questionnaire and visual analog scale. Pink Esthetic Score/White Esthetic Score were used for the professional esthetic evaluations of dental specialists. RESULTS: Overall patient satisfaction was high (87.42 ± 11.86). Compared with implant supported single-tooth restorations, patients with implant-supported bridges had lower OHIP scores (P = 0.001) and were relatively less satisfied with particular aspects of dental implant treatment (eg, cleanability, phonetics, surgical discomfort, and pretreatment information). Generally, type of prosthesis, history of soft/hard tissue augmentation, and reason for tooth loss had a clear impact on the extent of patients' satisfaction, esthetic considerations regarding treatment outcome, and their perceptions toward dental implant treatment (P < 0.05). CONCLUSIONS: Fixed implant-supported restorations generally provide with high levels of satisfaction and oral health-related quality of life.


Assuntos
Implantes Dentários , Prótese Dentária Fixada por Implante , Estética Dentária , Satisfação do Paciente , Qualidade de Vida , Planejamento de Prótese Dentária , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Bucal , Inquéritos e Questionários , Resultado do Tratamento
7.
Food Chem ; 221: 87-90, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27979286

RESUMO

This study presents a novel method to determine erucic acid in canola oil samples by using Raman spectroscopy and chemometric analysis. The oil mixtures were prepared at various concentrations of erucic acid ranging from 0% to 33.56% (w/w) through binary combinations of different oils. In order to predict erucic acid content, Raman spectroscopy and GC results were correlated by means of partial least squares analysis. High coefficient of determination values was obtained for both calibration and validation data sets, which are 0.990 and 0.982, respectively. The results of the present study reveal the potential of Raman spectroscopy for rapid determination (45s) of erucic acid in canola oil. Further research would be useful to improve the method to put it forward as an alternative to GC in the erucic acid analysis.


Assuntos
Ácidos Erúcicos/análise , Óleos de Plantas/química , Análise Espectral Raman , Óleo de Brassica napus
8.
Food Chem ; 212: 183-8, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27374522

RESUMO

A rapid and in situ method has been developed to detect and quantify adulterated milk powder through adding whey powder by using laser induced breakdown spectroscopy (LIBS). The methodology is based on elemental composition differences between milk and whey products. Milk powder, sweet and acid whey powders were produced as standard samples, and milk powder was adulterated with whey powders. Based on LIBS spectra of standard samples and commercial products, species was identified using principle component analysis (PCA) method, and discrimination rate of milk and whey powders was found as 80.5%. Calibration curves were obtained with partial least squares regression (PLS). Correlation coefficient (R(2)) and limit of detection (LOD) values were 0.981 and 1.55% for adulteration with sweet whey powder, and 0.985 and 0.55% for adulteration with acid whey powder, respectively. The results were found to be consistent with the data from inductively coupled plasma - mass spectrometer (ICP-MS) method.


Assuntos
Contaminação de Alimentos/análise , Leite/química , Análise Espectral/métodos , Soro do Leite/química , Animais
9.
J Food Sci Technol ; 51(10): 2382-92, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25328177

RESUMO

The use of corn oil in white cheese production instead of milk fat was investigated and its effects on the quality parameters of cheese were studied. It was demonstrated that the use of corn oil significantly affected the levels of dry matter, fat in dry matter, protein, salt in dry matter and titratable acidity and pH value of samples (p < 0.05). The water-soluble nitrogen based ripening indices of cheeses increased throughout the ripening period. However, there were not large quantitative differences among the peptide profiles of all the cheese samples. The polyunsaturated fatty acids (PUFA), the polyunsaturated to saturated fatty acid ratios (PUFA/SFA) and total cis fatty acid contents were found to be higher whilst the saturated fatty acid and trans fatty acid content were found to be lower than those of the control cheese (p < 0.05). It was found that the use of corn oil instead of milk fat in cheese production decreased the cholesterol content of the cheese samples (p < 0.05). The sensory scores of corn oil cheese were almost similar to the control cheese. The results indicated that corn oil utilization in cheese production has commercial potential in overcoming the defects related to fat reduction.

10.
J Oral Maxillofac Res ; 5(2): e5, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25089177

RESUMO

OBJECTIVES: Nitrosative stress plays an essential role in the pathogenesis of periodontal disease. The aim of this study is to analyze the gingival crevicular fluid and saliva nitrite and nitrate levels in periodontally healthy and diseased sites. MATERIAL AND METHODS: A total of 60 individuals including, 20 chronic periodontitis and 20 gingivitis patients and 20 periodontally healthy controls participated in the present study. Probing depth, clinical attachment level, bleeding on probing, gingival index and plaque index were assessed, gingival crevicular fluid (GCF) and saliva samples were obtained from the subjects, including 480 GCF samples and 60 unstimulated whole saliva samples. Nitrite and nitrate were analyzed by Griess reagent. RESULTS: Total GCF nitrite levels were higher in gingivitis and periodontitis groups (1.07 [SD 0.62] nmol and 1.08 [SD 0.59] nmol) than the control group (0.83 [SD 0.31] nmol) (P < 0.05) but did not differ significantly between gingivitis and periodontitis groups (P > 0.05). The difference in GCF nitrate level was not significant among the control, gingivitis and periodontitis groups (7.7 [SD 2.71] nmol, 7.51 [SD 4.16] nmol and 7.38 [SD 1.91] nmol). Saliva nitrite and nitrate levels did not differ significantly among three study groups. Saliva nitrate/nitrite ratios were higher in periodontitis and gingivitis groups than the control group. A gradual decrease in nitrate/nitrite ratio in GCF was detected with the presence of inflammation. CONCLUSIONS: It may be suggested that nitrite in gingival crevicular fluid is a better periodontal disease marker than nitrate and may be used as an early detection marker of periodontal inflammation, and that local nitrosative stress markers don't show significant difference between the initial and advanced stages of periodontal disease.

11.
J Periodontol ; 85(3): e47-56, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24144270

RESUMO

BACKGROUND: Volumetric alterations in gingival crevicular fluid (GCF) are widely accepted to be associated with periodontal health/disease. The volume/flow of GCF was shown to be affected by an array of methodological factors. However, relatively limited information is available on whether GCF is subject to circadian rhythm. The main aim of the present study is to assess the possible presence/absence of GCF circadian rhythm. The impact of the sampling technique on daytime volumetric variations is also analyzed. METHODS: The possible daily volumetric variations of GCF with 2-hour intervals (from 08:00 to 18:00 hours) were assessed in 100 tooth sites and 600 GCF samples. Only maxillary incisors were included to eliminate any potential volumetric differences due to tooth dimensions. To analyze the potential impact of sampling technique on GCF volume and daytime variations, at one site modified intracrevicular sampling technique (MIST) was used, whereas the contralateral site was sampled with a deep intracrevicular sampling technique (DIST). Clinical periodontal parameters of the GCF sites were also recorded. RESULTS: No significant daily variations in GCF volume could be detected. Higher volumetric measures were observed in inflamed subgroups compared with healthy subgroups (P <0.05). MIST was equivalent to DIST with regard to mean GCF volumes and the possible daytime volumetric alterations. CONCLUSIONS: Within the limits of the present study, it can be suggested that daytime variations did not have significant impact on GCF volume. The sampling methodology had no apparent impact on the circadian periodicity of GCF.


Assuntos
Ritmo Circadiano/fisiologia , Líquido do Sulco Gengival/metabolismo , Adulto , Feminino , Gengivite/classificação , Gengivite/metabolismo , Humanos , Incisivo , Masculino , Maxila , Pessoa de Meia-Idade , Índice Periodontal , Bolsa Periodontal/classificação , Bolsa Periodontal/metabolismo , Manejo de Espécimes/métodos , Fatores de Tempo , Adulto Jovem
12.
Food Chem ; 141(4): 4333-43, 2013 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-23993623

RESUMO

In this study, the utility of Raman spectroscopy (RS) with chemometric methods for quantification of multiple components in the fermentation process was investigated. Vinegar, the product of a two stage fermentation, was used as a model and glucose and fructose consumption, ethanol production and consumption and acetic acid production were followed using RS and the partial least squares (PLS) method. Calibration of the PLS method was performed using model solutions. The prediction capability of the method was then investigated with both model and real samples. HPLC was used as a reference method. The results from comparing RS-PLS and HPLC with each other showed good correlations were obtained between predicted and actual sample values for glucose (R(2)=0.973), fructose (R(2)=0.988), ethanol (R(2)=0.996) and acetic acid (R(2)=0.983). In conclusion, a combination of RS with chemometric methods can be applied to monitor multiple components of the fermentation process from start to finish with a single measurement in a short time.


Assuntos
Ácido Acético/análise , Saccharomyces cerevisiae/metabolismo , Análise Espectral Raman/métodos , Ácido Acético/metabolismo , Meios de Cultura/química , Meios de Cultura/metabolismo , Etanol/análise , Etanol/metabolismo , Fermentação , Frutose/análise , Frutose/metabolismo , Glucose/análise , Glucose/metabolismo , Saccharomyces cerevisiae/química
13.
Menopause ; 20(1): 94-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22968257

RESUMO

OBJECTIVE: The risk of primary ovarian insufficiency (POI) increases in association with autoimmune conditions. Adequate intake of vitamin D (vit D) and trace elements is required for the immune system to function efficiently. The aim of this study was to evaluate vit D, zinc, and copper blood levels in women with POI who had given birth to at least one child and in women with normal menstrual cycles. METHODS: This was a cross-sectional, case-control study involving 63 participants divided into two groups: the study group, which is composed of 35 women with POI, and the control group, which is composed of 28 women with normal menstrual cycles. Serum concentrations of zinc, vit D, and copper were determined for each participant. RESULTS: Women with POI had significantly higher serum copper levels and copper-to-zinc ratio but significantly lower serum vit D and zinc levels when compared with the healthy control group. Serum follicle-stimulating hormone levels were inversely correlated with zinc and vit D levels and positively correlated with the copper-to-zinc ratio and copper levels. Vit D levels were inversely correlated with follicle-stimulating hormone levels, copper-to-zinc ratio, and copper levels and positively correlated with zinc levels. CONCLUSIONS: Most women with POI are deficient in vit D. Zinc, copper, and vit D seem to correlate with hormonal status in the participants. The present study may generate hypotheses for future studies that will investigate the possible mechanisms behind alterations in trace elements and vit D deficiency in women with POI and whether these changes could be used to screen for the risk of developing POI.


Assuntos
Cobre/sangue , Insuficiência Ovariana Primária/sangue , Ubiquitina-Proteína Ligases/sangue , Vitamina D/sangue , Adulto , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos Transversais , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Hormônio Luteinizante/sangue
14.
Transfus Apher Sci ; 48(1): 11-3, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22854326

RESUMO

We recently encountered a 35-year old man who suffered from frequent hypoglycemia. His blood test revealed the presence of high and suppressed level of insulin with supressed C-peptide levels, hypothalamic-pituitary axis was normal response in hypoglycemia and negative for anti-insulin antibody. Endocrinological and imaging data eliminated the possibility of insulinoma. His symptoms responded well to the therapy of prednisolone (60 mg/day) and plasmapheresis. We followed up the patient over the subsequent 6 months without remarkable lesions. He has had no further recurrences of hypoglycemia. We believe that the antiinsulin receptor antibody might have induced hypoglycemia in this patient.


Assuntos
Hipoglicemia/terapia , Plasmaferese/métodos , Prednisolona/uso terapêutico , Adulto , Humanos , Hipoglicemia/sangue , Hipoglicemia/diagnóstico , Hipoglicemia/tratamento farmacológico , Masculino
15.
Food Chem ; 136(3-4): 1444-52, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23194547

RESUMO

The aim of this study was to quantify glucose, fructose, sucrose and maltose contents of honey samples using Raman spectroscopy as a rapid method. By performing a single measurement, quantifications of sugar contents have been said to be unaffordable according to the molecular similarities between sugar molecules in honey matrix. This bottleneck was overcome by coupling Raman spectroscopy with chemometric methods (principal component analysis (PCA) and partial least squares (PLS)) and an artificial neural network (ANN). Model solutions of four sugars were processed with PCA and significant separation was observed. This operation, done with the spectral features by using PLS and ANN methods, led to the discriminant analysis of sugar contents. Models/trained networks were created using a calibration data set and evaluated using a validation data set. The correlation coefficient values between actual and predicted values of glucose, fructose, sucrose and maltose were determined as 0.964, 0.965, 0.968 and 0.949 for PLS and 0.965, 0.965, 0.978 and 0.956 for ANN, respectively. The requirement of rapid analysis of sugar contents of commercial honeys has been met by the data processed within this article.


Assuntos
Carboidratos/análise , Mel/análise , Redes Neurais de Computação , Análise Espectral Raman/métodos , Modelos Teóricos
16.
Anal Bioanal Chem ; 403(7): 2009-17, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22552785

RESUMO

A new method based on surface-enhanced Raman spectroscopy (SERS) has been developed for sensitive and rapid detection of melamine. Spherical magnetic-core gold-shell nanoparticles (AuNPs) and rod-shaped gold nanoparticles (nanorods) labeled with a Raman-active compound were used to form a complex with the melamine molecules. 5,5'-Dithiobis(2-nitrobenzoic acid) was used as Raman-active compound because it is readily adsorbed by a gold nanoparticle surface forming a self-assembled monolayer (SAM) and has strong Raman scattering at 1330 cm(-1), because of the symmetric NO(2) stretch. The calibration curve was obtained by plotting Raman band area at 1330 cm(-1) against melamine concentration. A linear relationship was obtained with a high determination coefficient (R(2)=0.997). The method was validated for linearity, sensitivity, precision (intra-day and inter-day repeatability), and recovery. In the model system, the limits of detection (LOD) and quantification (LOQ) were 0.38 and 1.27 mg L(-1), respectively. For melamine-spiked milk samples, LOD and LOQ values were 0.39 mg L(-1) and 1.30 mg L(-1), respectively. Intra and inter-day precision were 3.73 and 4.94 %, respectively. This method was applied to samples of skimmed milk that had been spiked with melamine at different concentrations. The recovery of the method was 95-109 % in the concentration range 2-15 mg L(-1), and average RSD was 1.71 %. Total analysis time was less than 15 min.


Assuntos
Ouro/química , Nanopartículas Metálicas , Leite/química , Análise Espectral Raman/métodos , Triazinas/química , Animais , Limite de Detecção , Microscopia Eletrônica de Transmissão , Reprodutibilidade dos Testes
17.
Talanta ; 82(2): 631-9, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20602947

RESUMO

In this study, a new, sensitive, and rapid assay was developed to quantitatively measure the proteolytic enzyme activity using the surface-enhanced Raman scattering (SERS) probe. Two different shapes of gold nanoparticles, gold nanosphere and nanorod particles were produced. SERS label, comprising self-assembled monolayers (SAMs) of Raman reporter molecule (5,5-Dithiobis (2-Nitrobenzoic acid), DTNB), was coated on the surface of the nanoparticles. Two different SERS-based analysis platforms were designed using gold-coated glass slide and polystyrene microtiter plate. The calibration curves were obtained by plotting the intensity of the SERS signal of symmetric NO(2) stretching of DTNB at 1326 cm(-1) vs. the protease concentration. The effects of nanoparticle geometry and assay platform on the protease assay were investigated and the best working combination of the parameters was selected as rod shaped SERS probe and gold-coated glass slide. The correlation between the protease activity and SERS signal was found to be linear within the range of 0.1-2 mU/mL (R(2)=0.979). The limit of detection (LOD) and limit of quantification (LOQ) values of the validated method were found as 0.43 and 1.30 mU/mL, respectively. The intra-day and inter-day precisions of the method, as relative standard deviation (RSD), were determined as 2.5% and 3.6%, respectively. The developed method was successfully applied for quantitative analysis of the commercial enzyme preparate that is used in cheese making process. It was also used for investigation of substrate specificity of protease enzyme towards the casein and bovine serum albumin. The proposed method has a flexibility to try different substrates for the detection of various enzyme activities.


Assuntos
Peptídeo Hidrolases/química , Peptídeo Hidrolases/metabolismo , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Análise Espectral Raman/métodos , Especificidade por Substrato , Fatores de Tempo
18.
Int J Food Microbiol ; 139(3): 202-5, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20356644

RESUMO

Aim of the present study was to investigate the detoxification of aflatoxin B(1) and patulin from aqueous solution by probiotic culture of Enterococcus faecium M74 and commercial culture of E. faecium EF031. The effect of the bacterial viability, incubation time and pH of the medium on the binding ability was tested. Also, binding stability was determined by washing the bacteria-mycotoxin complexes with phosphate buffer saline. Both M74 and EF031 strains have the ability to remove aflatoxin B(1) and patulin. While M74 removes 19.3 to 30.5% of aflatoxin B(1) and 15.8 to 41.6% of patulin, EF031 removes 23.4 to 37.5% of aflatoxin B(1) and 19.5 to 45.3% of patulin throughout a 48 h incubation period. The removal of aflatoxin B(1) and patulin was highest at pH 7.0 and 4.0, respectively. The stability of the aflatoxin B(1) and patulin complexes formed with the bacterial strains was found to be high. The viability of the bacteria did not have any significant effect on the detoxification of aflatoxin B(1) and patulin. Detoxification properties of E. faecium could represent new strategies for a possible application in the human diet and animal feed.


Assuntos
Aflatoxina B1/metabolismo , Enterococcus faecium/metabolismo , Patulina/metabolismo , Probióticos , Biotransformação , Meios de Cultura , Concentração de Íons de Hidrogênio , Viabilidade Microbiana
19.
Lipids ; 44(5): 405-13, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19280240

RESUMO

The aim of this study was to determine the fatty acid composition and trans fatty acid and fatty acid contents of breast milk in Turkish women and to find the effect of breastfeeding mothers' diet on trans fatty acid and fatty acid composition. Mature milk samples obtained from 50 Turkish nursing women were analyzed. Total milk lipids extracts were transmethylated and analyzed by using gas liquid chromatography to determine fatty acids contents. A questionnaire was applied to observe eating habits and 3 days dietary records from mothers were obtained. Daily dietary intake of total energy and nutrients were estimated by using nutrient database. The mean total trans fatty acids contents was 2.13 +/- 1.03%. The major sources of trans fatty acids in mothers' diets were margarines-butter (37.0%), bakery products and confectionery (29.6%). Mothers who had high level of trans isomers in their milk consumed significantly higher amounts of these products. Saturated fatty acids, polyunsaturated fatty acids and monounsaturated fatty acids of human milk constituted 40.7 +/- 4.7%, 26.9 +/- 4.2% and 30.8 +/- 0.6% of the total fatty acids, respectively. The levels of fatty acids in human milk may reflect the current diet of the mother as well as the diet consumed early in pregnancy. Margarines, bakery products and confectionery are a major source of trans fatty acids in maternal diet in Turkey.


Assuntos
Dieta , Ácidos Graxos/análise , Leite Humano/química , Ácidos Graxos trans/análise , Adulto , Aleitamento Materno , Cromatografia Gasosa , Registros de Dieta , Feminino , Humanos , Gravidez , Inquéritos e Questionários , Turquia , Adulto Jovem
20.
J Agric Food Chem ; 55(26): 10787-94, 2007 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-18038980

RESUMO

The fatty acid, sn-2 fatty acid, triacyglycerol (TAG), tocopherol, and phytosterol compositions of kernel oils obtained from nine apricot varieties grown in the Malatya region of Turkey were determined ( P<0.05). The names of the apricot varieties were Alyanak (ALY), Cataloglu (CAT), Cöloglu (COL), Hacihaliloglu (HAC), Hacikiz (HKI), Hasanbey (HSB), Kabaasi (KAB), Soganci (SOG), and Tokaloglu (TOK). The total oil contents of apricot kernels ranged from 40.23 to 53.19%. Oleic acid contributed 70.83% to the total fatty acids, followed by linoleic (21.96%), palmitic (4.92%), and stearic (1.21%) acids. The s n-2 position is mainly occupied with oleic acid (63.54%), linoleic acid (35.0%), and palmitic acid (0.96%). Eight TAG species were identified: LLL, OLL, PLL, OOL+POL, OOO+POO, and SOO (where P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl), among which mainly OOO+POO contributed to 48.64% of the total, followed by OOL+POL at 32.63% and OLL at 14.33%. Four tocopherol and six phytosterol isomers were identified and quantified; among these, gamma-tocopherol (475.11 mg/kg of oil) and beta-sitosterol (273.67 mg/100 g of oil) were predominant. Principal component analysis (PCA) was applied to the data from lipid components of apricot kernel oil in order to explore the distribution of the apricot variety according to their kernel's lipid components. PCA separated some varieties including ALY, COL, KAB, CAT, SOG, and HSB in one group and varieties TOK, HAC, and HKI in another group based on their lipid components of apricot kernel oil. So, in the present study, PCA was found to be a powerful tool for classification of the samples.


Assuntos
Ácidos Graxos/análise , Fitosteróis/análise , Óleos de Plantas/química , Prunus/química , Tocoferóis/análise , Triglicerídeos/análise , Sementes/química , Turquia
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