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1.
Se Pu ; 37(10): 1064-1070, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642285

RESUMO

An analytical method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for detecting chlorate and perchlorate residues in milk power. Chlorate and perchlorate in milk power were extracted using a 0.1% (v/v) formic acid-acetonitrile solution. The extract was centrifuged at 10000 r/min for 10 min, and the supernatant was cleaned up on a PRiME HLB column. Separation of chlorate and perchlorate was performed on an ion-exchange column (Thermo Scientific Acclaim TRINITY P1, 50 mm×2.1 mm, 3 µm) by gradient elution using acetonitrile and 20 mmol/L ammonium acetate solution as the mobile phase. The analytes were identified by MS/MS. Quantification was achieved using internal standards. Chlorate and perchlorate demonstrated good linearity in the ranges of 2.0-40.0 and 1.0-20.0 µg/L, respectively, with correlation coefficients (r2) greater than 0.999. The limits of quantification (LOQs) of chlorate and perchlorate were found to be 15.0 and 7.5 µg/kg, respectively. The recoveries of chlorate and perchlorate ranged from 89.24% to 107.85% at the three spike levels of 30.0, 60.0, and 120.0, and 15.0, 30.0, and 60.0 µg/kg, respectively, with relative standard deviations (RSDs) ranging from 3.15% to 10.42% (n=6). This method is convenient, rapid, accurate, and efficient, thus demonstrating its suitability for use in the determination of chlorate and perchlorate in milk power.


Assuntos
Cloratos/análise , Contaminação de Alimentos/análise , Leite/química , Percloratos/análise , Animais , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem
2.
Se Pu ; 37(10): 1084-1089, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642287

RESUMO

The trade volume of imported dairy products is increasing with the increase of per capita consumption of dairy products, thus it is the great significant thing to control the quality of dairy products from other countries. The investigation finds that the proline content of imported liquid milk ultra high temperature instantaneous sterilization (UHT) milk (commonly known as normal temperature milk) is significantly higher than that of domestic UHT milk, that a risk of overheating and adding reconstituted milk exists for the imported UHT milk. Although it is currently unable to regulate the source and processing technology of imported dairy products, some certain indicators that reflect the process conditions are often used to monitor the quality of dairy products in the field of heat treatment process control of dairy products. Proline is produced during the processing of dairy products and is a marker that reflects the processing conditions. This paper briefly describes the research status of nine markers used to evaluate in the processing of dairy products at home and abroad, with the aim of providing a theoretical basis for improving the regulatory system for the processing of dairy products in China, and to protect consumer rights.


Assuntos
Laticínios/análise , Manipulação de Alimentos , Leite/química , Animais , Biomarcadores , China , Temperatura Alta , Controle de Qualidade
3.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 35(8): 695-701, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31638566

RESUMO

Objective To accurately and rapidly detect and type five classical Staphylococcal enterotoxins (SEs) by array-ELISA using a combination of a chip and ELISA. Methods SEs were prepared by prokaryotic expression and affinity chromatography. Hybridoma cells were injected intraperitoneally into mice to prepare ascites. A monoclonal antibody was obtained by ascites purification. The sensitivity and specificity of the antibody were evaluated by ELISA. The antibody was printed in one cell, and the sensitivity and specificity of array-ELISA were evaluated. Results Except for the detection limit of Staphylococcal enterotoxin C (SEC) being 10 ng/mL, 0.0001 ng/mL SEs could be detected by array-ELISA in PBS. The detection limit was 0.001-10 ng/mL for SEs in milk. The specificity was 100% in both PBS and milk. No cross reaction was observed between SEs. Additionally, no cross reaction was observed between SEB and botulinum toxin. Conclusion Array-ELISA has been successfully established, and it can simultaneously detect and discriminate five classical SEs within one sample sensitively and specifically.


Assuntos
Técnicas de Química Analítica , Enterotoxinas , Ensaio de Imunoadsorção Enzimática , Staphylococcus aureus , Animais , Técnicas de Química Analítica/métodos , Técnicas de Química Analítica/normas , Enterotoxinas/análise , Ensaio de Imunoadsorção Enzimática/normas , Limite de Detecção , Camundongos , Leite/química , Staphylococcus aureus/química
4.
Se Pu ; 37(11): 1215-1220, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642275

RESUMO

A gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) method was established for the simultaneous determination of nine flavor compounds (hydrocoumarin, vanillin, coumarin, ethyl vanillin, methyl vanillin, 7-methylcoumarin, 7-methyoxycoumarin, 7-ethoxy-4-mrthyl coumarin, pyranocoumarin) in pasteurized milk. The samples were extracted with ethanol and subjected to whirlpool oscillation. After centrifugation, the supernatant was filtered through a membrane, and the components were separated on a DB-5MS column. The nine analytes were detected by GC-MS/MS in the multiple reaction monitoring (MRM) mode and quantified by a matrix-matched external standard method. Good linearities in the range of 1-200 µg/L were observed for the nine flavor compounds. The linear correlation coefficients (R2) were greater than 0.997. The limits of detection and limits of quantification were 0.002-0.1 µg/kg and 0.001-2 µg/kg, respectively. The average recoveries were 90.3%-110.6%. Both the intra-day and inter-day RSDs were less than 10%. The developed method is simple, rapid, accurate and sensitive, and can be used for the simultaneous determination of the nine flavor compounds in pasteurized milk.


Assuntos
Leite/química , Paladar , Animais , Cromatografia Gasosa-Espectrometria de Massas , Pasteurização
5.
J Agric Food Chem ; 67(41): 11527-11535, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31536347

RESUMO

A magnetic nanoporous organic polymer (M-NOP) was prepared as a new adsorbent with excellent extraction capacity and rapid adsorption kinetics for 5-nitroimidazoles (5-NDZs). Hence, a rapid and effective method was proposed for determination of 5-NDZs in milk by combining M-NOP-based magnetic solid-phase extraction with high-performance liquid chromatography. Main extraction conditions were investigated. Under optimal conditions, good linear response was achieved in a range of 2.4-100 ng mL-1 with a lower detection limit of 0.8-1.0 ng mL-1. High accuracy with a recovery of 80.0-116.0% for the fortified samples, good repeatability with relative standard deviation below 10%, and a high enrichment factor of 97-111 were obtained. The rapid adsorption of 5-NDZs on M-NOP is mainly driven by H-bonding, π-stacking, and polar interactions. Finally, the M-NOP-based method was successfully used to determine 5-NDZs in milk samples. The M-NOP is expected to present promising application in the extraction and quantitative analysis of other compounds.


Assuntos
Magnetismo/métodos , Leite/química , Nitroimidazóis/isolamento & purificação , Polímeros/química , Adsorção , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Limite de Detecção , Nanoporos , Nitroimidazóis/química , Polímeros/síntese química , Porosidade
6.
Shokuhin Eiseigaku Zasshi ; 60(4): 113-118, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31474652

RESUMO

We evaluated measurement uncertainty and performed internal quality control of an ELISA test for allergens in egg and milk, using control samples. For the evaluation of measurement uncertainty, the following three important factors were identified: 1) Differences in test-kit lots, 2) Different-day reproducibility, 3) Same-time reproducibility. A three-stage nested design was used, and the combined standard uncertainty of the three factors mentioned above was calculated based on the results obtained. Measurement uncertainty was defined as the expanded uncertainty obtained by multiplying the combined standard uncertainty by a coverage factor of two. As a result, the expanded uncertainty of egg was 1.9 µg/g when the total egg protein concentration was 13.4 µg/g, and the expanded uncertainty of milk was 1.8 µg/g when the total milk protein concentration was 13.5 µg/g. For the internal quality control, we first set the reference range of the measured value of the control sample, using the obtained combined standard uncertainty as an index. Each control sample was then measured for every test, and we concluded that the test was performed without any errors, when the result of the control sample was within the reference range. Second, the measured values of the control samples were plotted on a graph for continuous monitoring. This enabled us to check whether inspection accuracy was maintained. There were no large chronological changes and no major differences between the standard deviations of the control samples and the combined standard uncertainty in egg or milk. Therefore, it was determined that the dispersion was at an acceptable range and inspection accuracy was maintained.


Assuntos
Alérgenos/análise , Ovos/análise , Ensaio de Imunoadsorção Enzimática , Leite/química , Controle de Qualidade , Animais , Reprodutibilidade dos Testes , Incerteza
7.
J Agric Food Chem ; 67(38): 10756-10763, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31483626

RESUMO

AFEX treatment of crop residues can greatly increase their nutrient availability for ruminants. This study investigated the concentration of acetamide, an ammoniation byproduct, in AFEX-treated crop residues and in milk and meat from ruminants fed these residues. Acetamide concentrations in four AFEX-treated cereal crop residues were comparable and reproducible (4-7 mg/g dry matter). A transient acetamide peak in milk was detected following introduction of AFEX-treated residues to the diet, but an alternative regimen showed the peak can be effectively mitigated. Milk acetamide concentration following this transition was 6 and 10 ppm for cattle and buffalo, respectively, but also decreased over time for cattle while tending to decrease (p = 0.08) for buffalo. There was no difference in acetamide concentration in the meat of cattle consuming AFEX-treated residues for 160 days compared to controls. Further investigation is necessary to determine the metabolism of acetamide in ruminants and a maximum acceptable daily intake for humans.


Assuntos
Acetamidas/análise , Ração Animal/análise , Bovinos/metabolismo , Produtos Agrícolas/química , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Carne/análise , Leite/química , Acetamidas/metabolismo , Amônia/química , Animais , Búfalos , Dieta/veterinária , Digestão , Leite/metabolismo
8.
Anim Genet ; 50(5): 430-438, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392738

RESUMO

Our previous genome-wide association study identified 83 genome-wide significant SNPs and 20 novel promising candidate genes for milk fatty acids in Chinese Holstein. Among them, the enoyl-CoA hydratase, short chain 1 (ECHS1) and enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH) genes were located near two SNPs and one SNP respectively, and they play important roles in fatty acid metabolism pathways. We herein validated whether the two genes have genetic effects on milk fatty acid traits in dairy cattle. By re-sequencing the full-length coding region, partially adjacent introns and 3000 bp up/downstream flanking sequences, we identified 12 SNPs in ECHS1: two in exons, four in the 3' flanking region and six in introns. The g.25858322C>T SNP results in an amino acid replacement from leucine to phenylalanine and changes the secondary structure of the ECHS1 protein, and single-locus association analysis showed that it was significantly associated with three milk fatty acids (P = 0.0002-0.0013). The remaining 11 SNPs were found to be significantly associated with at least one milk fatty acid (P = <0.0001-0.0040). Also, we found that two haplotype blocks, consisting of nine and two SNPs respectively, were significantly associated with eight milk fatty acids (P = <0.0001-0.0125). However, none of polymorphisms was observed in the EHHADH gene. In conclusion, our findings are the first to indicate that the ECHS1 gene has a significant genetic impact on long-chain unsaturated and medium-chain saturated fatty acid traits in dairy cattle, although the biological mechanism is still undetermined and requires further in-depth validation.


Assuntos
Bovinos/genética , Enoil-CoA Hidratase/genética , Ácidos Graxos/análise , Leite/química , Polimorfismo de Nucleotídeo Único , Animais , Feminino , Desequilíbrio de Ligação , Masculino
9.
Environ Monit Assess ; 191(8): 526, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363853

RESUMO

Biomonitoring has been used to disclose the public health impact of contaminated sites. This study aimed at setting up good practices to apply biomonitoring targeting animal matrixes to design risk-based surveillance and exposure assessment plans. A nine-step protocol targeting farmed animals was devised and tested in three case study areas including (1) a waste dump, (2) a waste incinerator, and (3) a secondary aluminum smelter. Between 2010 and 2012, in each study area, the following 9-step best practices were applied: hazard identification, GIS project creation, risk area delimitation, control area selection, receptors (livestock) identification, farms and matrixes selection, sampling study design, on-farm secondary sources exclusion, and statistical and geostatistical analysis. Dairy farms and free-range laying hens were the primary targets: eggs from both risk and control areas and milk from risk areas were sampled and submitted for detection of selected tracking contaminants compatible with the putative sources. Comparison data (risk vs. control) of heavy metal concentrations in eggs were available only for case study 2, whereas egg comparison data of persistent organic pollutants were available for all the risk-control pairs. After taking into account potential secondary sources, no concern from metals was arisen, whereas high concentrations of persistent organic pollutants were detected in all risk areas; however, only for the aluminum smelter case study, the contamination was broad and higher in the risk area compared with the control one. The protocol has proved to be easily applicable and flexible to varying contexts and able to provide helpful data to inform risk management decisions.


Assuntos
Ovos/análise , Monitoramento Ambiental/métodos , Monitoramento Ambiental/normas , Poluentes Ambientais/análise , Metais Pesados/análise , Leite/química , Animais , Bovinos , Galinhas , Feminino , Sistemas de Informação Geográfica , Itália , Medição de Risco , Instalações de Eliminação de Resíduos
10.
Exp Parasitol ; 205: 107735, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31381870

RESUMO

Two experiments were performed to determine whether oral administration of copper oxide capsules controlled helminthic infections in Lacaune sheep without acute collateral effects on animal health. In experiment 1, 48 multiparous lactating sheep (60.1 ±â€¯8.5 kg) were stratified according to initial number of eggs (Haemonchus contortus) per gram of feces (EPG) and were assigned randomly to 1 of two treatments (24 sheep/treatment): no oral administration (control) or oral administration of two copper capsules (treated; approximately 58 mg copper/kg body weight). Blood and fecal samples were collected on days 0, 15 and 45. Animals treated with copper capsules showed lower of EPG, eosinophils, acetylcholinesterase (AChE) in whole blood, and lower butyrylcholinesterase (BChE) activity in serum. Treated sheep had higher erythrocyte numbers, hemoglobin concentrations, hematocrit, and lymphocyte numbers. In experiment 2, 12 male lambs negative for helminths and coccidia were assigned randomly to one of two treatments (six lambs/treatment): control or treated (one copper capsule; approximately 58 mg copper/kg body weight); the experiment was designed to determine whether the results of experiment 1 were due to treatment or parasitism. Blood samples were collected on days 0, 5, 10 and 15 and fecal samples were collected on days 0, 7 and 15. Treated animals showed greater concentrations of lymphocytes; however, treatment had no effect on other hemogram variables, AChE and BChE activities, or levels of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, creatinine, urea, albumin, total protein, and reactive oxygen species. These data suggest that copper capsules in dairy sheep efficiently controlled H. contortus infections. Treatment was not harmful to lambs during the first 15 days, i.e. there were no signs of acute toxicity.


Assuntos
Cobre/administração & dosagem , Hemoncose/veterinária , Helmintíase Animal/tratamento farmacológico , Lactação , Doenças dos Ovinos/tratamento farmacológico , Acetilcolinesterase/sangue , Administração Oral , Animais , Butirilcolinesterase/sangue , Cápsulas , Cobre/uso terapêutico , Indústria de Laticínios , Resíduos de Drogas , Eosinófilos/efeitos dos fármacos , Contagem de Eritrócitos/veterinária , Fezes/parasitologia , Feminino , Hemoncose/tratamento farmacológico , Hemoncose/prevenção & controle , Helmintíase Animal/sangue , Helmintíase Animal/prevenção & controle , Hematócrito/veterinária , Hemoglobinas/análise , Contagem de Linfócitos/veterinária , Masculino , Leite/química , Contagem de Ovos de Parasitas/veterinária , Paridade , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/sangue , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/prevenção & controle
11.
J Sci Food Agric ; 99(14): 6515-6521, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31321772

RESUMO

BACKGROUND: Fortification of animal products with natural bioactive compounds appears to improve their quality and protects consumers against oxidation effects. An experiment was therefore conducted to examine the effects of hesperidin or naringin on milk oxidative stability, yield, composition, coagulation properties, and the fatty acid profile in dairy sheep. Thirty-six Chios ewes were assigned to four groups. A control group was fed a concentrate diet without supplementation. The other three groups were provided with the same diet further supplemented with hesperidin (6000 mg kg-1 ), naringin (6000 mg kg-1 ), or α-tocopheryl acetate (200 mg kg-1 ). The efficacy of flavonoids after a change in diet composition that lowered milk oxidation values by itself was also tested. The duration of the experiment was 28 days with alfalfa hay being the only forage source for the first 14 days, whereas after the 15th day a mixture of alfalfa hay and wheat straw (65:35) was provided. RESULTS: The oxidative stability of milk was improved after 14 days of addition of the examined flavonoids (P < 0.05). Milk malondialdehyde (MDA) values were also decreased as a result of flavonoid dietary supplementation, 14 days after the modification of the forage source. On the other hand, no significant differences in yield, chemical composition, coagulation properties, and fatty acid profile of ewe milk were observed among the treatments throughout the experiment. CONCLUSION: Enrichment of dairy ewes' diets with hesperidin and naringin might be effective in improving milk's oxidative stability without any effects on the milk's chemical composition, coagulation properties, and fatty acid profile. © 2019 Society of Chemical Industry.


Assuntos
Suplementos Nutricionais/análise , Flavanonas/administração & dosagem , Hesperidina/administração & dosagem , Leite/metabolismo , Ovinos/metabolismo , Ração Animal/análise , Animais , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Feminino , Leite/química , alfa-Tocoferol/análise , alfa-Tocoferol/metabolismo
12.
J Dairy Sci ; 102(9): 7723-7733, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255261

RESUMO

Milk fat adulteration is a common issue in Central Asia. To assess the current situation in the commercial milk market, 17 milk samples were checked for fatty acid (FA) and sterol profiles to detect potential adulteration using multivariate analysis. Analysis of FA and sterols was performed using gas chromatography with flame ionization detection and gas chromatography with mass-spectrometric detection, respectively. Cluster analysis of FA profiles revealed 3 types of milk samples: (1) samples containing a higher proportion of short-chain FA, (2) samples containing a higher proportion of long-chain FA, and (3) samples with significant amounts of C18 FA. Analysis of sterols showed that samples included (1) milk fat containing 100% cholesterol, sometimes with traces of phytosterols, (2) milk fat with high proportions of ß-sitosterol and campesterol, and (3) milk fat containing high proportions of brassicasterol. We found significant relationships between FA profiles and sterol profiles. The profiles were compared with vegetable oil patterns reported in the literature. More than 50% of the samples appeared to be counterfeited. We conclude that identification of adulteration in milk can be based solely on determination of sterol patterns.


Assuntos
Ácidos Graxos/análise , Contaminação de Alimentos/análise , Leite/química , Esteróis/análise , Animais , Colestadienóis/análise , Colesterol/análogos & derivados , Colesterol/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Fitosteróis/análise , Óleos Vegetais/análise , Sitosteroides/análise
13.
J Dairy Sci ; 102(9): 7640-7654, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255272

RESUMO

Automatic milking systems (AMS), first introduced on dairy farms in the 1990s, rapidly spread across many countries. This technology is based on the voluntary milking of dairy cattle in a completely automated process, which relies on computer management, with a substantial average increase in milking frequency. Compared with conventional milking, AMS significantly alters herd management, with important implications on economic, technical, and social aspects of farming, on animal physiology, health, and well-being. These aspects are explored in an extensive body of research. In contrast, the effects of AMS adoption on milk quality are often overlooked. This review draws together both positive and negative effects of AMS on the milk production chain, particularly emphasizing the variations of hygienic and compositive characteristics of raw milk and their interplay, as compared with milk obtained with conventional milking. Scattered and sometimes conflicting literature exists on whether and how these variations may influence quality and yield of the derived dairy products. Current scientific knowledge on these crucial aspects is thus reviewed, with particular focus on milk technological suitability for being processed into dairy products having the target characteristics in terms of taste, structure, on-storage stability, and sustainability. Provided the managing conditions are optimized, AMS allow increased milk production, mostly due to more frequent milking, without compromising the milk characteristics that are crucial to food industry for processing. Nevertheless, specific biochemical aspects related to the changed milking interval, which determines the duration of enzyme activities and bacterial growth in milk, need further research.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/métodos , Higiene , Leite/química , Robótica/métodos , Animais , Laticínios/análise , Indústria de Laticínios/instrumentação , Feminino , Qualidade dos Alimentos , Lactação , Leite/microbiologia , Tecnologia
14.
J Food Sci ; 84(8): 2289-2296, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31334849

RESUMO

The sensory characteristics of goat yogurt could be greatly improved by integrating to a culture typical of yogurt starters, Streptococcus thermophilus, Lactobacillus delbrueckii spp. bulgaricus, with cultures of Leuconostoc lactis. The addition of L. lactis requires the use of the definition of  "fermented milk" to the product, although it is prepared according to the same technology. The experimental plan has designed the use of inoculation with a bacterial concentration of at least 109 , for each microbial species considered, with the aim of increasing the probiotic effect of yogurt and fermented milk. Descriptive analysis of the samples was conducted using the profile sheet obtained applying the consensus profiling method (UNI EN ISO 13299:2010) by a trained panel. The acceptability of our products was evaluated by 62 consumers through 7-points hedonic scale. The results of this study indicated that the addition of L. lactis to the traditional yogurt starter produced a noticeable improvement to the sensory characteristics of fermented goat milk. PRACTICAL APPLICATION: To improve the sensory characteristics of goat's yogurt to make it more acceptable to the consumer and increase market demand we tested the integration of Leuconostoc lactis to typical starter cultures. The experimentation carried out tested different combinations of fermenting microorganisms with the aim of developing a better flavor as compared to that of traditional yogurt, which is often unpleasant to consumers. The addition of L. lactis to the starter culture of the goat's milk results in less aggressive aromatic notes and greater appreciation as confirmed by consumers who tested the product.


Assuntos
Microbiologia de Alimentos/métodos , Paladar , Iogurte/análise , Animais , Feminino , Fermentação , Cabras , Humanos , Lactobacillus delbrueckii/metabolismo , Leuconostoc/metabolismo , Masculino , Leite/química , Leite/microbiologia , Probióticos/metabolismo , Streptococcus thermophilus/metabolismo , Iogurte/microbiologia
15.
J Sci Food Agric ; 99(14): 6455-6461, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31294826

RESUMO

BACKGROUND: The illegal undeclared addition of reconstituted milk powder to ultra-heat treated (UHT) milk to lower production costs is an example of economically motivated adulteration. This activity not only defrauds consumers but also places honest traders at a disadvantage, which could damage the reputation of milk producers and reduce the integrity of the markets. In this research, a non-targeted analytical strategy that combines proton (1 H) nuclear magnetic resonance (NMR) spectroscopy with a chemometrics data mining tool was developed for the authentication of bovine UHT milk. RESULTS: Unsupervised principal component analysis was used to distinguish UHT and tap-water-reconstituted powdered milk. Partial least squares-discriminant analysis (PLS-DA) with R2 (Y) and Q2 equal to 0.859 and 0.748, respectively, was used to differentiate UHT and reconstituted milk samples. Three compounds were selected as biomarkers to distinguish UHT and reconstituted milk and identified according to the standard NMR-spectra database. Finally, a PLS-DA model was established, according to the characteristic spectral bands, to identify UHT milk and reconstituted milk. CONCLUSION: This procedure demonstrated the feasibility of using non-targeted NMR profiling combined with chemometric analysis to combat mislabeling and fraudulent practices in milk production. © 2019 Society of Chemical Industry.


Assuntos
Biomarcadores/análise , Contaminação de Alimentos/análise , Metabolômica/métodos , Leite/química , Espectroscopia de Prótons por Ressonância Magnética/métodos , Animais , Bovinos , Análise Discriminante , Análise de Componente Principal
16.
J Dairy Sci ; 102(8): 6959-6970, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31255265

RESUMO

In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (ß-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.


Assuntos
Suplementos Nutricionais , Kluyveromyces/enzimologia , Lactase/administração & dosagem , Metilcelulose/análogos & derivados , Leite/química , Animais , Cápsulas , Fenômenos Químicos , Composição de Medicamentos/veterinária , Proteínas Fúngicas/administração & dosagem , Hidrólise , Lactose/metabolismo , Metilcelulose/química , Leite/metabolismo , Tamanho da Partícula , Pós , Resinas Vegetais/química , Paladar , Triglicerídeos/química
17.
Artigo em Inglês | MEDLINE | ID: mdl-31287378

RESUMO

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method, in conjunction with multiwalled carbon nanotube purification, was developed to determine the mefentrifluconazole levels in grapes, cucumbers, tomatoes, peppers, wheat, maize, eggs, milk, pork, chicken, and fish. After purification, tandem mass spectrometry of mefentrifluconazole required <3.0 min. Matrix-matched external standard curves were used to quantify the residual mefentrifluconazole. The method meets the requirements of the European Union Document SANTE/11813/2017. Quantification was linear between 5 and 500 µg/kg (R2 ≥ 0.9988), and both the intra- and interday relative standard deviations were ≤13.7%. Analyte recovery ranged from 81.5% to 107.6%. The limit of mefentrifluconazole quantification was 5 µg/kg for all matrices. The method successfully detected and quantified mefentrifluconazole that had been applied to cucumbers and tomatoes grown in a test field. These results imply that the proposed method is effective and reliable for detecting mefentrifluconazole residues in plant- and animal-derived foods.


Assuntos
Fluconazol/análogos & derivados , Fluconazol/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Animais , Capsicum/química , Galinhas , Cromatografia Líquida de Alta Pressão , Cucumis sativus/química , Ovos/análise , Peixes , Lycopersicon esculentum/química , Leite/química , Carne Vermelha/análise , Alimentos Marinhos/análise , Espectrometria de Massas em Tandem , Fatores de Tempo , Triticum/química , Vitis/química , Zea mays/química
18.
Environ Monit Assess ; 191(8): 523, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31359252

RESUMO

This study examined the presence of Aflatoxin M1 (AFM1) in raw milk, cheese, and cheese halva samples collected from the Çanakkale province of Turkey. Raw milk, Ezine cheese, and cheese halva samples (n 120 for each group, total 360) were collected from bazaars, local manufacturers, and supermarkets in the Çanakkale province of Turkey during 2014 and 2015. ELISA was used to detect AFM1 in these products. AFM1 mean values were 5.14-78.69, 19.43-158.30, and 50.25-213.50 ng/kg in raw milk, Ezine cheese, and cheese halva samples, respectively. The levels of AFM1 in four raw milk samples (3.3%) were above the legal limits, whereas AFM1 levels in Ezine cheese and cheese halva samples were within the legal limits according to the requirements of the Turkish Food Codex and the European Commission. Turkey has a wealth of cultures and local delicacies. Over previous decades, gastronomic tourism in Turkey has become popular owing to an increase in visitor demand, and traditional foods are being exported abroad. Our research investigated the presence of AFM1 in these types of food products. Çanakkale is one of the best representative cities in the Marmara Region in Turkey as a source of these unique products.


Assuntos
Aflatoxina M1/análise , Queijo/análise , Contaminação de Alimentos/análise , Leite/química , Animais , Cidades , Ensaio de Imunoadsorção Enzimática , Leite/normas , Turquia
19.
J Dairy Sci ; 102(9): 8343-8351, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301830

RESUMO

Methionine (Met) is one of the 2 most limiting amino acids for milk production in dairy cow diets. The accepted "ideal" ratio of lysine (Lys) to Met (L:M) when formulating diets is 3:1. However, blood from cows fed corn silage-based diets without supplemental rumen-protected Met averages approximately 3.6:1 L:M. Recent in vivo research on cattle immunonutrition has revealed that the immune system could benefit from greater Met supply. To study more closely the effects of different L:M ratios, blood polymorphonuclear cells (PMN) were isolated from 5 Holstein cows in mid-lactation (238 ± 20 d postpartum, 33.8 ± 3.8 kg of milk/d; mean ± SD). The PMN were incubated at 3 different levels of L:M (3.6:1, 2.9:1, or 2.4:1) and stimulated with lipopolysaccharide (LPS) at either 0 or 50 µg/mL for 2 h at 37°C. Target genes were associated with cytokines, pathogen recognition, nuclear receptors, killing mechanisms, and Met and glutathione metabolism. Data were subjected to ANOVA using PROC MIXED in SAS, with L:M, LPS, and their interaction as fixed effects. Stimulation with LPS upregulated genes related to cytokines (IL1B, TNF, IL10 and IL6) and nuclear receptors, including nuclear factor kappa B (NFKB1) and glucocorticoid receptor (NR3C1), and downregulated the mRNA abundance of chemokine receptor 1 (CXCR1), lysozyme (LYZ) and glutathione reductase (GSR). A linear decrease was observed in the mRNA abundance of TNF when L:M was decreased. A similar response was observed for interleukin-1 receptor-associated kinase 1 (IRAK1) and NFKB1 abundance in cells stimulated with LPS (linear effect). A linear increase of LYZ mRNA expression as L:M decreased was detected in unstimulated cells. Furthermore, a decrease in L:M led to a linear decrease of superoxide dismutase 1 (SOD1) mRNA abundance in cells challenged with LPS. Overall, LPS challenge triggered the activation of isolated PMN from mid-lactation cows. However, data suggest the use of a shorter incubation time to capture the peak response and not the resolution of the inflammatory response as in the present study. Our results indicate a possible involvement of Met in modulating PMN inflammatory and oxidative stress status and in helping the resolution of inflammation after initial stimulation.


Assuntos
Bovinos/imunologia , Redes Reguladoras de Genes , Imunidade/genética , Metionina/farmacologia , Neutrófilos/imunologia , Animais , Bovinos/genética , Células Cultivadas , Dieta/veterinária , Suplementos Nutricionais , Feminino , Lactação/fisiologia , Lipopolissacarídeos/imunologia , Metionina/administração & dosagem , Leite/química , Rúmen/metabolismo
20.
Food Chem ; 299: 125065, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31284246

RESUMO

Determination of lead at trace levels was achieved by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after the preconcentration with deep eutectic solvent-based liquid phase microextraction (DES-LPME). A green solvent was used to extract lead from the aqueous solution. Parameters affecting the extraction efficiency and determination were optimized in the aim to lower the detection limit. Under the optimum experimental and instrumental conditions, the proposed method exhibited a linear range between 50 and 1000 µg L-1, and the limits of detection and quantitation (LOD and LOQ) were found to be 8.7 and 29.0 µg L-1, respectively. The detection power was improved by 48 times using DES-LPME-SQT-FAAS method with respect to conventional FAAS system. Recovery studies were carried out in raw milk samples to check the accuracy and the applicability of the developed method and the percent recoveries obtained were between 102.5 and 103.2% for the spiked raw milk samples.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Chumbo/análise , Microextração em Fase Líquida , Leite/química , Solventes/química , Espectrofotometria Atômica , Animais , Chumbo/isolamento & purificação , Limite de Detecção , Quartzo , Água/química
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