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1.
Talanta ; 236: 122833, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635223

RESUMO

A dynamic pH junction was used in capillary electrophoresis (CE-DAD) to on-line preconcentrate, separate, and determine trace amounts of sulfonamide antibiotics (SAs) in milk and yoghurt samples in this study. A sample matrix with 0.15% acetic acid and 10% methanol (MeOH) at a pH of 4.0, and a background electrolyte (BGE) that contained 35 mM sodium citrate with 10% MeOH at a pH of 8.5, and an acidic barrage of 0.4% acetic acid with 10% MeOH at a pH of 2.5 were utilised to achieve a stacking effect for SAs through a dynamic pH junction. Under optimised conditions, the proposed preconcentration method showed good linearity (30-500 ng/mL, r2 ≥ 0.9940), low limits of detection (LODs) of 4.1-6.3 ng/mL, and acceptable analytes recovery (81.2-106.9%) with relative standard deviations (RSDs) within 5.3-13.7 (n = 9). The limits of quantification (LOQs) were below the maximum residue limit approved by the European Union (EU) in this type of matrices. Sensitivity enhancement factors of up to 129 were reached with the optimised dynamic pH junction using CE with a diode array detector (DAD). The method was used to determine SAs in fresh milk, low-fat milk, full-cream milk, and yoghurt samples.


Assuntos
Antibacterianos , Iogurte , Animais , Eletroforese Capilar , Concentração de Íons de Hidrogênio , Leite , Sulfonamidas
2.
Talanta ; 236: 122842, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635232

RESUMO

A fluorescent aptasensor based on sensitized terbium(III) luminescence was constructed to detect melamine in milk. Tb3+ as the fluorescence probe can be sensitized by a guanine-rich single-stranded DNA sequence, so the complementary sequence of the polythymidine aptamer (cDNA) was modified with six consecutive guanine bases (G6). In the absence of melamine, melamine aptamer combined with cDNA to form a double helix structure, and G6 hybridized with the extended cytosine bases in the aptamer, resulting in low fluorescence intensity of Tb3+. In the presence of melamine, cDNA was released due to the specific recognition of melamine to the aptamer, resulting in stronger sensitized fluorescence intensity of Tb3+. Under the optimum conditions, the linear concentration of melamine in the milk ranged from 1.0 µg/mL to 10.0 µg/mL. This aptasensor can be used for the accurate and rapid detection of melamine in milk with a detection limit of 0.02 µg/mL, and has the advantages of high sensitivity, high efficiency, simple operation and low cost.


Assuntos
Luminescência , Leite , Animais , Limite de Detecção , Leite/química , Triazinas/análise
3.
Food Chem ; 366: 130533, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34274704

RESUMO

We performed a multiscale study to understand the impact of pure exogenous compounds at low concentration on the crystallization of triacylglycerols (TAGs) in anhydrous milk fat (AMF). We selected butyric acid, an inhibitor of crystallization, and palmitic acid, a promotor, to investigate the influence of the chain length. Tripalmitin was also used as a promotor to assess the impact of fatty acid esterification. Melted blends containing the additives (1 wt%) were quenched at 25 °C. X-ray scattering data showed that AMF TAGs crystallized directly in the ß'-2L form. The presence of additives did not modify the nanostructure of TAG crystals. However, they significantly altered the microstructure of AMF, as revealed by polarized light microscopy and rheology. This study emphasizes the interest of a multiscale approach to gain knowledge about the behavior of complex fat blends and of the use of modulators at low concentration to monitor their textural properties.


Assuntos
Ácidos Graxos não Esterificados , Nanoestruturas , Animais , Cristalização , Ésteres , Leite
4.
Food Chem ; 366: 130554, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284188

RESUMO

Standard fermentation (SF) mainly affected the metabolism of glycerophospholipid and sphingolipid, and increased the total lipid content of goat milk. Content of total lipid was decreased by magnetic fermentation compared with SF, mainly due to triacylglycerol and diacylglycerol. Comprehensive characteristic of lipids dynamic changes during standard and magnetic fermentation was performed using high-throughput quantitative lipidomics. Totally, 488 lipid molecular species covering 12 subclasses were detected, and triacylglycerol was the highest levels, followed by diacylglycerol and phosphoethanolamine in the whole fermentation stage. Specifically, except for ceramide and simple Glc series, the content of all polar lipids in SF was dropped and neutral lipids subjoined. Compared with SF, the decrease of triacylglycerol (1752.47 to 784.78 µg/mL), diacylglycerol (60.36 to 24.89 µg/mL) and simple Glc series (4.36 to 2.40 µg/mL) were observed, while ceramide (6.54 to 25.87 µg/mL) increased, suggesting magnetic fermentation as effective approach to potentially improve the nutritional of goat milk.


Assuntos
Lipídeos , Leite , Animais , Fermentação , Cabras , Lipídeos/análise , Fenômenos Magnéticos , Leite/química , Valor Nutritivo
5.
Food Chem ; 366: 130648, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34325245

RESUMO

A novel label-free fluorescence aptasensor was established for chloramphenicol (CAP) detection by DNA four-arm junction-assisted target recycling and SYBR Green I dye-aided fluorescence-signal amplification. The CAP aptamer was hybridized to its complementary strand (primer) to form a double-stranded primer/aptamer complex. In the presence of CAP, aptamers can specifically bind with CAP to dissociate primers, which can trigger the self-assembly of four hairpins to continuously generate DNA four-arm junctions. After digesting the excess hairpins using T7 exonuclease, SYBR Green I was inserted into the base pair-rich DNA four-arm junctions, which led to a significant increase in fluorescence intensity. Under optimal conditions, the developed aptasensor can detect CAP in a linear range of 1.0 pg mL-1 to 10 ng mL-1 with a detection limit of 0.72 pg mL-1. The recovery rates in milk and honey ranged from 90.3% to 106.6%. Thus, the method shows substantial potential for CAP detection in food products.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Animais , Cloranfenicol/análise , DNA , Limite de Detecção , Leite/química
6.
Food Chem ; 367: 130700, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352694

RESUMO

Present study prepared curcumin-loaded nanoliposomes using bovine milk, krill phospholipids and cholesterol; and investigated the effects of cholesterol on membrane characteristics, storage stability and antibacterial properties of the curcumin nanoliposomes. Bovine milk phospholipids which have higher saturation than krill phospholipids resulted in formation of curcumin-loaded nanoliposomes with higher encapsulation efficiency (84.78%), larger absolute value of zeta potential and vesicle size (size: 159.15 ± 5.27 nm, zeta potential: -28.3 ± 0.62 mV). Cholesterol helps to formation of a more hydrophobic, compact and tighter bilayer membrane structure which improved the storage stability of nanoliposomes under alkaline (66.25 ± 0.46%), heat (43.25 ± 0.69%) and sunlight (49.44 ± 1.78%) conditions. In addition, curcumin-loaded nanoliposomes can effectively target infectious bacteria which secrete pore-forming toxins such as Staphylococcus aureus by causing the bacterial cell wall to lysis. Findings from present work can guide future development of novel antibacterial agents for use in food preservation.


Assuntos
Curcumina , Fosfolipídeos , Animais , Antibacterianos , Bovinos , Colesterol , Lipossomos , Leite , Tamanho da Partícula
7.
Food Chem ; 367: 130763, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384984

RESUMO

Developing highly sensitive and visual methods for rapid detection of antibiotics is significant to ensure food quality and safety. To meet the requirement of nitrofuran antibiotics detection, luminescent fusiform Al(III)-containing metal-organic frameworks (Al-MOF) nanosheets were successfully synthesized by one-step hydrothermal method. And then, the nanosheet served as a fluorescent probe to detect nitrofuran via the inner-filter effect mechanism. The developed sensor allowed sensitive and selective detection of nitrofuran with good linear relationships. And, the detection limit (LOD) values were estimated to be 0.53, 0.838 and 0.583 µM for nitrofurazone, nitrofurantoin and furazolidone detection, respectively. The practical application of the proposed system was verified by HPLC in spiked milk samples with satisfying recoveries ranging from 88.14 to 126.21% and low relative standard deviations of 2.85 ~ 8.13%. Moreover, we designed fluorescent test papers for semi-quantitative detection of nitrofuran via naked-eye colorimetric assay. The established method provides an alternative strategy for semiquantitative detection of nitrofuran.


Assuntos
Estruturas Metalorgânicas , Nitrofuranos , Animais , Antibacterianos/análise , Corantes Fluorescentes , Leite/química , Nitrofuranos/análise
8.
Food Chem ; 368: 130820, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34416488

RESUMO

Two commercially available food grade fungal protease preparations (Fungal Protease 31,000 and Fungal Protease 60000) were found to hydrolyse bovine acid whey proteins but left the beta-lactoglobulin (ß-Lg) intact under the processing conditions used. Comparative analysis before and after hydrolysis of bovine acid whey, by 1D- and 2D-PAGE, RP-HPLC and intact-mass mass spectrometry showed that the ß-Lg remains intact and in high yield after hydrolysis by the fungal proteases. The ß-Lg could be separated from the whey protein peptide hydrolysate by ultrafiltration. Subjecting whey fraction to hydrolysis with the fungal protease preparations provides a procedure, under relatively mild conditions, to generate a highly enriched ß-Lg fraction. ß-Lg is recognised as a valued material in the food, pharmaceutical and cosmetic industries due to its properties such as gelling and foaming. The enriched ß-Lg preparation would also have application in areas such as nanoencapsulation.


Assuntos
Lactoglobulinas , Leite , Animais , Bovinos , Hidrólise , Proteínas do Leite , Peptídeo Hidrolases , Soro do Leite , Proteínas do Soro do Leite
9.
Food Chem ; 368: 130866, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34438178

RESUMO

The objective of this work was to investigate the effect of fermentation conditions on c9,t11-conjugated linoleic acid (CLA) synthesized by Lactobacillus casei and the variation of physicochemical characteristics, including pH, viable cell number, syneresis and texture profile, of fermented soy milk (FSM) during storage at 4 °C for 28 days. Fermentation in 7°Brix of soy milk (SM) supplemented with 0.1% linoleic acid and incubated at 37 °C for 72 h was found to be the optimal conditions for c9,t11-CLA biosynthesis. Within the storage of 14 days, viable cell number, total flavonoid content, water-holding capacity, spontaneous syneresis and texture profile in FSM remained stable. During the storage of 28 days, the viable cell number and c9,t11-CLA level were higher than 6.58 log CFU/mL and 816.33 µg/g, respectively.


Assuntos
Ácidos Linoleicos Conjugados , Leite de Soja , Animais , Suplementos Nutricionais , Ácido Linoleico , Leite
10.
Food Chem ; 369: 130998, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34507088

RESUMO

High Temperature-Short Time (HTST) pasteurization was proposed as an alternative to Holder pasteurization (HOP) to increase the retention of specific human milk (HM) bioactive proteins. The present study explored whether HTST and HOP differently affect peptide release during simulated preterm infant gastrointestinal digestion. Raw (RHM), HOP- and HTST- pasteurized HM were digested using an in vitro dynamic system, and the identified peptides were analyzed by mass spectrometry and multivariate statistics. Before digestion, 158 peptides were identified in either RHM, HTST- or HOP- HM, mostly (84.4%) originating from ß-casein (CASB). During gastric digestion, HOP-HM presented a greater number and more abundant specific CASB peptides. A delayed release of peptides was observed in RHM during the intestinal phase, with respect to both pasteurized HM. Although limited to gastric digestion, the HM peptidomic profile differed according to the pasteurization type, and the pattern of the HTST peptides showed a greater similarity with RHM.


Assuntos
Leite Humano , Pasteurização , Animais , Digestão , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Leite , Peptídeos , Temperatura
11.
Talanta ; 237: 122958, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736683

RESUMO

Immunoglobulin G (IgG) is a significant ingredient of immunological activity in milk and colostrum, the activity and content of which is easily disturbed by potentially conditional variant during sterilization. Therefore, developing robust methods for the detection of IgG levels in milk is especially important. Herein, protein A from the Staphylococcus aureus functionalized silica colloidal crystalline film (SCC@SPA) sensing unit combined with ordered porous layer interferometry (OPLI) for IgG detection in untreated bovine milk was developed. Calibration curves in milk and buffer were set up by the variations of the optical thickness (OT) of the sensing unit after the IgG association and dissociation phases. The influence of temperature on the level of IgG was evaluated. Furthermore, the identification of IgG levels with pasteurized milk and ultrahigh temperature (UHT) sterilized milk from the market randomly was successfully carried out without any sample pretreatment. More importantly, compared with other methods, this novel method has the advantages of convenient operation, low cost, and suitability for point-of-care (POC) testing.


Assuntos
Colostro , Leite , Animais , Bovinos , Feminino , Imunoglobulina G , Interferometria , Porosidade , Gravidez
12.
Talanta ; 237: 122968, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736692

RESUMO

A microextraction pretreatment for powdered milk analysis, relying on the formation of a natural deep eutectic solvent is proposed. It relies on the in situ hydrolysis of milk fats (triglycerides) which yields fatty acids as precursors in the formation of the natural deep eutectic solvent. As a proof-of-concept, the innovation was applied to the determination of thirteen polycyclic aromatic hydrocarbons in powdered milk samples by HPLC with fluorometric detection. The alkaline hydrolysis of milk triglycerides minimized sample matrices interference through removal of proteins and fats, and led to formation of natural deep eutectic solvent precursors (fatty acids) directly from the sample components. Addition of only one precursor (terpenoid) was then required. Menthol and thymol (natural terpenoids) were investigated as deep eutectic solvent precursors for microextraction of polycyclic aromatic hydrocarbons. Under the selected experimental conditions, limits of detection were estimated within the 0.002-0.09 µg kg-1 range. The innovation provided satisfactory (70-91%) extraction of hydrophobic analytes from complex powdered milk matrices containing hydrophobic components (triglycerides) without the need for hazardous organic solvents. The RSD values were <5.2%.


Assuntos
Microextração em Fase Líquida , Hidrocarbonetos Policíclicos Aromáticos , Animais , Ácidos Graxos , Hidrólise , Leite/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Solventes , Triglicerídeos
13.
Food Chem ; 370: 131312, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34788957

RESUMO

A rapid and sensitive hybrid nanosensor was reported with a colorimetric and fluorometric readout system using graphene quantum dots (GQDs) and gold nanoparticles (AuNPs) for the detection of gentamicin (GENTA) in milk and egg samples. In the presence of AuNPs, the fluorescence (FL) intensity of GQDs gradually decreased due to the inner filter effect (IFE) of AuNPs on the FL intensity of GQDs. In addition of GENTA into AuNPs, AuNPs get aggregated and changed their color from red to blue, due to which the IFE of AuNPs reduced and hence, enhanced FL intensity of GQDs with varying concentration of GENTA from 1.03 to 16.55 µM with a lower detection limit of 0.422 µM and 0.493 µM in colorimetric and fluorimetric systems, respectively. The practical application of the developed nanosensor is tested against the real spiked sample. The excellent and straightforward recovery efficiency of the developed nanosensor for the determination of GENTA and can be used as a promising and adaptable tool for speedy monitoring of food quantity.


Assuntos
Grafite , Nanopartículas Metálicas , Pontos Quânticos , Animais , Gentamicinas , Ouro , Limite de Detecção , Leite
14.
Environ Pollut ; 292(Pt B): 118457, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742818

RESUMO

A high demand exists in bisphenols (BPs) screening studies for quick, reliable and straightforward analytical methods that generate data faster and simultaneously. Herein, we describe a combination of enzymatic probe sonication (EPS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for quick extraction and simultaneous quantification of eight important BPs in animal-derived foods. Results obtained demonstrated that the ultrasonic probe power could not only enhance the enzymatic hydrolysis efficiency, but also accelerate the liquid-liquid extraction procedure. Under optimized EPS parameters, one sample could be exhaustively extracted within 120 s, as compared with 12 h needed for the conventional enzymatic extraction which is more suitable for high-throughput analysis. The method was successfully applied to analyze residual BPs in animal-derived foods collected from Beijing, China. Widespread occurrence of BPA, BPS, BPF, BPAF, BPP, and BPB were found, with detection frequencies of 65.2%, 42.4%, 33.7%, 29.4%, 28.3%, and 27.2%, respectively. The highest total concentration levels of BPs (sum of the eight BPs analyzed, ΣBPs) were found in chicken liver (mean 12.2 µg/kg), followed by swine liver (6.37 µg/kg), bovine muscle (3.24 µg/kg), egg (2.03 µg/kg), sheep muscle (2.03 µg/kg), chicken muscle (1.45 µg/kg), swine muscle (1.42 µg/kg), and milk (1.17 µg/kg). The estimated daily intake (EDI) of BPs, based on the mean and 95th percentile concentrations and daily food consumptions, was estimated to be 5.687 ng/kg bw/d and 22.71 ng/kg bw/d, respectively. The human health risk assessment in this work suggests that currently BPs do not pose significant risks to the consumers because the hazard index (HI) was <1.


Assuntos
Sonicação , Espectrometria de Massas em Tandem , Ração Animal , Animais , Compostos Benzidrílicos/análise , Bovinos , Cromatografia Líquida , Leite/química , Ovinos , Suínos
15.
Chemosphere ; 287(Pt 4): 132373, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34600005

RESUMO

Monitoring of pathogenic bacteria plays a vital role in precluding foodborne disease outbreaks. In this research work, a genosensor based on innovative label-free DNA was developed for the detection of Salmonella. typhimurium (S. typhimurium) in the milk samples. To realize this objective, bimetallic Fe/Mn MOF is synthesized and mixed with methyl-ß-cyclodextrin (MßCD) and AuNPs which are then stabilized on multi-walled carbon nanotubes (MWCNTs), and the obtained nanocomposite is immobilized on the Au electrode surface. Different characterization methods such as FE-SEM, TEM, EDS, FTIR, and XRD were used for investigating the particle size and morphological features. Electrochemical and impedimetric techniques were used for exploring the applicability of the fabricated genosensor. Under optimal circumstances, LOD and LOQ have acquired at 0.07 pM and 0.21 pM. Moreover, an extensive linear range of 1 pM-1 µM was resulted for ss-tDNA (single-stranded target DNA), R2 obtained 0.9991. The recoveries were obtained 95.6-104%. Great selectivity against one, two, and three-base mismatched sequences was also shown for fabricated biosensing assay. Furthermore, negative genosensing assay control for investigating selectivity was provided by the ss-tDNAs of Haemophilusinfluenzae and Shigella dysenteriae bacteria. Well-fabricated genosensing bio-assay represents better performance, great specificity, high sensitivity, increased active sites, and finally results in an increase in the electron transfer rate. It is to be noted that the organized genosensing bio-assay is capable of being re-used and re-generated in a straightforward manner to estimate the hybridization process.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Nanotubos de Carbono , Animais , DNA , Técnicas Eletroquímicas , Ouro , Limite de Detecção , Leite , Salmonella typhimurium/genética , beta-Ciclodextrinas
16.
Food Chem ; 370: 131057, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34536781

RESUMO

Advances in Matrix-assisted Laser Desorption/Ionization -Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) have led to its supremacy for complex assessment of food authenticity studies, like dairy products fraud, holding promise for the discovery of potential authenticity (bio)markers. In this study, an integrated untargeted protein-based workflow in combination with advanced chemometrics is presented, to address authenticity challenges in PDO feta cheese which is legally manufactured by the mixture of sheep/goat milk. Potential markers attributed to specific animal origin were found from protein profiles acquired for authentic feta and white cheeses (prepared from cow milk), belonging to 4 kDa-18.5 kDa mass area. Rapid detection of feta cheese adulteration from cow milk was also achieved down to 1% adulteration level. The discriminative models showed high predictive ability for feta cheese authenticity (Q2 = 0.920, RMSEE = 0.053) and its adulteration (Q2 = 0.835, RMSEE = 0.121), introducing a reliable approach in routine analysis. The methodology was successfully applied in detection of cow milk in sheep yoghurt.


Assuntos
Queijo , Animais , Bovinos , Queijo/análise , Feminino , Contaminação de Alimentos/análise , Leite , Ovinos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Fluxo de Trabalho
17.
Food Chem ; 370: 131027, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34537432

RESUMO

The pollution caused by estrogens in the environment and food has received increasing attention. It is still challenging for on-site immunochromatographic assay (ICA) detection of estrogens. The performance of the prepared probes plays a decisive role in the sensitivity and stability of the ICA system. The published probes usually directly couple the detection antibody to the label, ignoring the influence of the label on the activity of the antibody. In this study, 17ß-estradiol (E2) was used as a model analyte for the ICA system. Two universal probes were constructed based on quantum dot nanobeads (QBs), recombinant protein A (SPA, from Staphylococcus aureus), and rabbit anti-mouse immunoglobulin G antibody (anti-IgG). The probes were prepared by coupling QBs with SPA, releasing anti-E2 monoclonal antibody (mAb), and maintaining its activity. The prepared universal probes can orient recognize the Fc region of mAb and fully expose its Fab region, improving the detection sensitivity of the ICA system. The free anti-E2 mAb and the universal probe (QBs@SPA or QBs@SPA@anti-IgG) were used as the detection antibodies and signal donors, respectively. The results show that the proposed ICA based on QBs@SPA and QBs@SPA@anti-IgG probes could detect E2 with IC50 of 8.83 and 0.93 ng/mL, respectively, within 15 min under optimal conditions. The recovery results of ICA based on QBs@SPA and QBs@SPA@anti-IgG probes showed good agreement with the findings of the high-performance liquid chromatography (HPLC) analysis for spiked samples. The developed ICA system based on universal probes was superior in terms of sensitivity, rapidity, and applicability, and held great promise for its implementation in detecting environmental and food small-molecule pollutants.


Assuntos
Leite , Pontos Quânticos , Animais , Anticorpos , Estradiol , Imunoensaio , Camundongos , Coelhos
18.
J Colloid Interface Sci ; 607(Pt 2): 1050-1060, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34571294

RESUMO

HYPOTHESIS: The rheology of milk fat, which is strongly related to its functionality, reflects multiscale structural transitions in the colloidal network formed by crystallizing triacylglycerols. EXPERIMENTS: To relate rheology to structure, early stages of milk fat crystallization at 15-22 °C were studied combining different techniques; XRD and microscopy to study structural changes, NMR to quantify the different structures, and rheology to evaluate their effect on macroscopic properties. FINDINGS: Network strength increased with the synchronized formation of micro- and nanostructures. A rheological response was only obtained when these structures became visibly connected on a microscale, and internal transitional changes could be detected with rheology. On the nanoscale, transitions were linked to the formation of specific crystal polymorphs. We quantified the formation of polymorphs commonly found in milk fat (α-2 and ß1'-2) and of two less commonly obtained polymorphs: ß-2 and ß2'-2. For the first time, the formation of these polymorphs was quantified and related to the composition of fat. Besides providing insights into the complex phase behavior of milk fat, this study shows that the structural transitions involved can be characterized and quantified by combining XRD with NMR and be detected at an early stage using rheology and microscopy.


Assuntos
Leite , Animais , Cristalização , Transição de Fase , Reologia , Triglicerídeos
19.
J Sci Food Agric ; 102(1): 132-138, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34057739

RESUMO

BACKGROUND: The human tongue is important in the oral processing of food and in sensory perception. Tongue topography could influence delicate differences in sensory perception. It is hypothesized that tongue surface roughness could alter oral lubrication status and affect perception of smoothness. Fifteen participants with varying levels of tongue surface roughness were recruited and tested. Participants' in situ oral lubrication status without and after consumption of fluid food (milk with varying fat content and maltodextrin solutions with different shear viscosities) was measured. Participants' smoothness sensory scores were also recorded. RESULTS: The in situ friction coefficient (0.299-1.505) was significantly positively correlated with tongue-surface roughness (54.6-140.0 µm) in all types of test fluid samples across participants. Oral lubrication was significantly decreased when participants consumed the test fluid samples compared with no liquid food consumption, for all test fluid sample types (P < 0.05). No significant differences in in situ friction coefficient were found after participants consumed different test fluid samples, and this was mainly attributed to the limited quantities of fluid residuals in the oral cavity after expectoration. Participants whose tongue surface roughness differed did not exhibit significant differences in smoothness perception with different test fluid samples. CONCLUSION: Tongue surface roughness has a strong impact on in situ oral lubrication, and fluid food intake reduces in situ oral lubrication significantly. Saliva film and tongue surface roughness might play greater roles in oral lubrication and smoothness sensory perception if fluid is expectorated after consumption. The association between oral physiology and texture perception still needs further elucidation. © 2021 Society of Chemical Industry.


Assuntos
Percepção Gustatória , Língua/química , Adulto , Animais , Gorduras/química , Gorduras/metabolismo , Feminino , Fricção , Humanos , Lubrificação , Masculino , Leite/química , Leite/metabolismo , Saliva/química , Saliva/fisiologia , Propriedades de Superfície , Língua/fisiologia , Viscosidade , Adulto Jovem
20.
J Hazard Mater ; 421: 126753, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34365237

RESUMO

For the first time, a novel nanocomposite, zeolitic imidazolate framework/magnetic layered double hydroxide (Fe3O4@LDH/ZIF), was successfully fabricated through in situ synthetic method with Fe3O4 as magnetic core and composite as shell. The resulting materials were characterized by XRD, TEM, FT-IR, VSM, TGA and nitrogen adsorption-desorption analysis. The Fe3O4@LDH/ZIF was employed as a sorbent in dispersive micro-solid phase extraction (D-µ-SPE) for enrichment of four endocrine disrupting compounds (EDCs) from milk samples prior to ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) analysis. The synthesized nanocomposite showed bigger specific surface area and better absorption capacity than Fe3O4@LDH. The equilibrium adsorption capacities (Qe, mg/g) of EDCs on the Fe3O4@LDH/ZIF reached up to 47.4-138.8 mg/g, mainly resulting from hydrogen bonding, π-π interaction and electrostatic interaction between EDCs and nanocomposite. Several variables affecting the extraction efficiency were investigated and optimized. The method displays low limits of detection (3-15 ng L-1), good linearity (10-5000 ng L-1), acceptable precision (RSD < 7.8%) and accuracy (RE < 5.2%). Satisfactory repeatability was obtained with RSD in the range of 1.2-7.8%. This work provides a promising approach for the development of new sorbent media in sample preparation for the improvement of analytical performance.


Assuntos
Nanocompostos , Zeolitas , Adsorção , Animais , Cromatografia Líquida de Alta Pressão , Hidróxidos , Limite de Detecção , Fenômenos Magnéticos , Leite , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Espectrometria de Massas em Tandem
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