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1.
Araz Bidari Mohammad Reza Ganjali Yaghoub Assadi Armin Kiani Parviz Norouzi 《Food Analytical Methods》2012,5(4):695-701
In this work, we have developed a sensitive and cost-effective preconcentration and quantification methodology for total mercury (Hg) at trace levels in food supplements of marine origin. Dispersive liquid–liquid microextraction was successfully employed for the preconcentration of mercury at trace levels prior to inductively coupled plasma atomic emission spectrometry. The mercury was extracted as mercury-1, 5-diphenyl-3-formazathiol complex, at pH 1.0 mediated by multidroplet formation of microextraction solvent assisted by disperser solvent. The lower limit of detection obtained under the optimal conditions was 0.24 μg L−1. The calibration graphs were linear up to 500 μg L−1. The precision of the method in terms of relative standard deviation was 4.8% for the concentration of 100 μg L−1. In order to validate the proposed method, a certified reference material RTC-QCI-049 was analyzed with the proposed procedure. Moreover, potential interference by 20 species was also evaluated. 相似文献
2.
Halil İbrahim Ulusoy Ramazan Gürkan Özlem Demir Songül Ulusoy 《Food Analytical Methods》2012,5(3):454-463
A new method has been developed for preconcentration of cobalt at trace levels in beverage samples using calcon carboxylic
acid as chelating agent and cetyl pyridinium chloride as an auxiliary ligand and entrapped into Triton X-114 prior to its
determination by flame atomic absorption spectrometry (FAAS). The main parameters affecting cloud point extraction (CPE) efficiency
such as pH, concentration of the complexing agent, cationic and nonionic surfactant concentration, salt effect, the equilibrium
time, and temperature were investigated and optimized. After optimization of the CPE conditions, a preconcentration factor
of 60, an enhancement factor of 106, and a detection limit of 0.20 μg L−1 by (R
2 = 0.9978) were obtained from a calibration curve constructed in the range of 0.7–100 μg L−1. The proposed preconcentration procedure was successfully applied to the determination of cobalt ions in some real samples
including natural drinking water, tap water, and beer and wine samples. The accuracy and validity of the proposed CPE/FAAS
method was tested by means of five repeated analysis of reference standard materials (TM-253, a low level fortified water
standard for trace elements). A good agreement between analytical results (28.8 and 28.5 μg L−1 with calibration curve and standard addition curve method, respectively) and certified value (27.9 μg L−1) for Co (p < 0.05) were obtained and verified by means of calibration curve and standard addition curve method using CPE procedure. 相似文献
3.
A solid-phase microextraction (SPME) procedure followed by gas chromatography electron capture detection (GC/ECD) for the
determination of triazole residues was developed. An experimental design with two steps was done. Firstly, a 26−2 fractional factorial design for screening several experimental variables (fiber-coating type, extraction temperature, extraction
time, stirring rate, desorption temperature, and desorption time) was done. After, a two-factor central composite design for
optimizing, the experimental conditions were carried out. The chosen experimental conditions were: fiber, PDMS/DVB; extraction
time, 45 min; extraction temperature, 60 °C; desorption time, 3 min; desorption temperature, 260 °C, and stirring speed, 500 rpm.
Using those conditions the limits of detection obtained for tetraconazole, myclobutanil, and diniconazole were in the order
of few μg L−1 in grape and apple liquid extracts. Recoveries were from 93.6% to 112.1%. Relative standard deviation ranged from 1.2% to
11.6% (apple) and 6.7 to 18.0% (grape). The method was applied to five grape samples and 13 apple samples collected in Navarra,
Rioja, and Basque Country. Quantification was performed by the standard addition method. Three standard additions by duplicate
covering adequate range concentration were used. Myclobutanil was found in three apple samples (110–122 μg L−1) and diniconazole in one grape sample (9.4 μg L−1). 相似文献
4.
Polycyclic aromatic hydrocarbons (PAHs) in traditional and industrial smoked beef and pork ham from Serbia 总被引:1,自引:0,他引:1
Jasna Djinovic Aleksandar Popovic Wolfgang Jira 《European Food Research and Technology》2008,227(4):1191-1198
Smoked beef and pork ham samples were analysed during process of smoking (after packing and storing) for the presence of the
16 EU priority PAHs via Fast GC/HRMS method. This study showed that there are differences in PAH contents between final smoked
beef ham samples from traditional smokehouse (TS) (3.9 μg kg−1) and industrial smokehouse (IS), (1.9 μg kg−1). Also there is a difference in PAH contents in final smoked pork ham samples (4.9 μg kg−1, TS; 4.2 μg kg−1, IS). In beef and pork ham samples from the same smokehouse different PAH contents were observed during smoking. The highest
content of examined PAHs in all beef and pork ham samples during smoking showed benzo[c]fluorene (BcL) (beef ham: from 0.3 μg kg−1 to 1.5 μg kg−1; pork ham: from 0.2 μg kg−1 to 2.1 μg kg−1).The maximum level for benzo[a]pyrene (BaP) of 5 μg kg−1 in smoked meat products was not exceeded in any samples. Correlation statistic analysis (P < 0.05) of obtained contents from samples both from TS and IS showed that BaP is a good marker both for 16 EU priority PAHs
and 12 IARC probably and possibly carcinogenic PAHs (IS: R
BaP/Σ16PAHs = 0.95, R
BaP/Σ12PAHs = 0.96; TS: R
BaP/Σ16PAHs = 0.71, R
BaP/Σ12PAHs = 0.88). 相似文献
5.
A separation–enrichment technique for the determination of trace amounts of copper(II), cobalt(II), lead(II), and iron(III)
as violuric acid chelates on multiwalled carbon nanotubes at pH 6.0 was established. Analytes were determined by flame atomic
absorption spectrometry. The effects of some analytical parameters like pH, amounts of violuric acid, flow rates, eluent type,
and sample volume were investigated. The influences of the matrix ions were also investigated. The relative standard deviations
for analyte elements were below 10%. The quantification limits of the analyte ions were found as 0.36 μg g−1 for copper, 0.43 μg g−1 for lead, 0.15 μg g−1 for cobalt, and 0.38 μg g−1 for iron. The accuracy of presented method was checked by the analysis of TMDA 54.4 fortified lake water, NIST SRM 1515 apple
leave, and HR-1 Humber river sediment certified reference materials. The method was applied to analyte contents of table salt
samples from different origin. The levels of iron in the analyzed table salt samples were found in the range of 1.6–6.4 μg g−1, while lead was found in only one sample as 5.0 μg g−1. In all other samples, cobalt, lead, and copper were found below the quantification limits of the analytes. 相似文献
6.
Gian Paulo G. Freschi Felipe M. Fortunato Carolina D. Freschi José Anchieta Gomes Neto 《Food Analytical Methods》2012,5(4):861-866
Tungsten permanent modifier with coinjection of Pd(NO3)2 and W–Ru permanent modifiers are proposed for the direct and simultaneous determination of As, Bi, Pb, Sb, and Se (group
1) and Co, Cr, Cu, Fe, and Mn (group 2), respectively, in milk by graphite furnace atomic absorption spectrometry. The performance
of modifiers was evaluated by means of thermal behavior of analytes, sensitivity, atomic signal profile, repeatability, graphite
tube lifetime, and background intensity. An air-assisted pyrolysis step was necessary to quantitative elimination of the organic
matter. After methods optimization, 14 commercial milk samples were analyzed. The found concentrations of As, Bi, Pb, Sb,
Se, Co, and Cr were lower than their limit of detection (2.13, 2.21, 1.49, 1.63, 2.05, 1.0, and 1.2 μg L−1, respectively). Concentrations of Cu, Fe, and Mn were in the 1.58–5.74 μg L−1, 9.79–49.3 μg L−1, and 2.25–4.08 μg L−1 intervals, respectively. The limits of detection for Cu, Fe, and Mn were 1.7, 5.3, and 2.0 μg L−1, respectively. The accuracy of methods was checked after analysis of two milk standard materials. Results for Cr, Cu, Fe,
Mn, Pb, and Mn were in agreement with certified values of SRMs at the 95% confidence level. Accuracy was also evaluated by
addition–recovery tests and recoveries in the 86–127% range were obtained for all elements. The use of pretreat platform of
graphite tubes with W or W–Ru allowed enlarging the lifetime of atomizer in 750 heating cycles. 相似文献
7.
A simple and rapid high-performance liquid chromatography (HPLC) procedure for the analysis of melamine in liquid milk and milk powder has been developed. Decrease of acetonitrile percentage and phosphate buffer concentration in mobile phase, and lowering of buffer pH and column temperature would benefit the retention of melamine on titania. Taking advantage of the ligand-exchange and hydrophilic interaction mixed retention mode on bare titania column, neither complex pretreatment nor ion-pair reagent was required. The whole analysis for one sample including sample pretreatment and HPLC analysis could be accomplished within 30 min. The method presented good linearity (R 2 = 0.9998) in a wide range of 0.02–10 μg mL−1. The limit of detection (3σ) and limit of quantification (10σ) of the method were 6 and 20 μg L−1, respectively, which were equivalent to 15 and 50 μg kg−1 melamine in liquid milk, 60 and 200 μg kg−1 melamine in milk powder, respectively. Such sensitivity could be compared with those obtained by HPLC with solid-phase extraction or HPLC coupled with tandem mass spectrometry and was adequate for the screening of melamine in tainted dairy products. The repeatability (RSDs) of the retention times and peak areas of 11 replicate detections of 1.0 μg mL−1 melamine were 0.32% and 2.5%, respectively. The intermediate precision on three consecutive days (RSDs, n = 6) of the retention times and peak areas were 1.1% and 2.3%, respectively. The recovery of spiked melamine in dairy samples ranged from 95.2% to 105%. The simplicity, sensitivity and rapidity of the proposed method make it an effective alternative detecting technique for melamine. 相似文献
8.
Ana Maria P. dos Santos Adriana Caires Oliveira Anderson Santos Souza Robson Mota de Jesus S��rgio L. C. Ferreira 《Food Analytical Methods》2011,4(4):567-573
Inductively coupled plasma optical emission spectrometry was used to determine the elements present in Chinese cabbage (Beta vulgaris). The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves. The study involved
57 samples that were collected in 13 Brazilian cities. Average concentrations of elements found per gram of Chinese cabbage
were as follows: 3.44 mg g−1 sodium, 5.09 mg g−1 potassium, 1.25 mg g−1 phosphorous, 0.85 mg g−1 calcium, 0.49 mg g−1 magnesium, 2.79 μg g−1 manganese, 9.50 μg g−1 iron, 0.74 μg g−1 copper, 14.28 μg g−1 zinc, and 6.44 μg g−1 strontium. Principal component analysis and hierarchical cluster analysis demonstrated that there is no systematic difference
in the mineral composition between the cabbage samples that were analyzed. 相似文献
9.
Aspergillus subolivaceus dextranase is immobilized on several carriers by entrapment and covalent binding with cross-linking. Dextranase immobilized
on BSA with a cross-linking agent shows the highest activity and considerable immobilization yield (66.7%). The optimum pH
of the immobilized enzyme is shifted to pH 6.0 as compared with the free enzyme (pH 5.5). The optimum temperature of the reaction
is resulted at 60 °C for both free and immobilized enzyme. Thermal and pH stability are significantly improved by the immobilization
process. The calculated K
m
of the immobilized dextranase (14.24 mg mL−1) is higher than that of the free dextranase (11.47 mg mL−1), while V
max of the immobilized enzyme (2.80 U μg protein−1) is lower than that of the free dextranase (11.75 U μg protein−1). The immobilized enzyme was able to retain 76% of the initial catalytic activity after 5.0 cycles. 相似文献
10.
Juliana Naozuka M��rcia A. M. S. da Veiga Eduardo M. Richter Thiago R. L. C. Paix?o L��cio Angnes Pedro V. Oliveira 《Food Analytical Methods》2011,4(1):49-56
Coconut water is a natural isotonic, nutritive, and low-caloric drink. Preservation process is necessary to increase its shelf
life outside the fruit and to improve commercialization. However, the influence of the conservation processes, antioxidant
addition, maturation time, and soil where coconut is cultivated on the chemical composition of coconut water has had few arguments
and studies. For these reasons, an evaluation of coconut waters (unprocessed and processed) was carried out using Ca, Cu,
Fe, K, Mg, Mn, Na, Zn, chloride, sulfate, phosphate, malate, and ascorbate concentrations and chemometric tools. The quantitative
determinations were performed by electrothermal atomic absorption spectrometry, inductively coupled plasma optical emission
spectrometry, and capillary electrophoresis. The results showed that Ca, K, and Zn concentrations did not present significant
alterations between the samples. The ranges of Cu, Fe, Mg, Mn, PO43−, and SO42− concentrations were as follows: Cu (3.1–120 μg L−1), Fe (60–330 μg L−1), Mg (48–123 mg L−1), Mn (0.4–4.0 mg L−1), PO43− (55–212 mg L−1), and SO42− (19–136 mg L−1). The principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to differentiate unprocessed
and processed samples. Multivariated analysis (PCA and HCA) were compared through one-way analysis of variance with Tukey–Kramer
multiple comparisons test, and p values less than 0.05 were considered to be significant. 相似文献
11.
Fengjie Cui Caixia Wan Yebo Li Zhe Liu Gireesh Rajashekara 《Food and Bioprocess Technology》2012,5(4):1278-1286
Lactic acid and cell production from whey permeate by Lactobacillus rhamnosus with different nutrient supplements were investigated in this study. Yeast extract was identified as the most effective nutrient
affecting lactic acid production. Increase in inoculum size from 0.05% to 1% (v/v) resulted in a substantial increase in lactic acid productivity from 0.66 to 0.83 g L−1 h−1 (P < 0.001). The optimal temperature for lactic acid production was 37 °C, while the highest cell production was obtained at
42 °C. When whey permeate and yeast extract concentrations were 6.8% (w/v) and 3 g L−1, respectively, lactic acid productivity reached 0.85 g L−1 h−1 after 48-h cultivation, which is 3.40 times of those without nutrient supplements. 相似文献
12.
Guozhen Fang Jinping Lu Mingfei Pan Wei Li Lei Ren Shuo Wang 《Food Analytical Methods》2011,4(4):590-597
A new direct competitive enzyme-linked immunosorbent assay (ELISA) with molecularly imprinted film as artificial antibody
was developed to detect ractopamine (RAC) in urine and pork samples. The imprinted film was directly synthesized on the well
surface of 96-well plate by an organic–inorganic hybrid technology and evaluated by fourier transform infrared (FT-IR), static,
and kinetic adsorption experiments. The imprinted film exhibited an antibody-like binding ability and rapid adsorption speed.
The established ELISA method gave a good sensitivity (IC50, 15.77 μg L−1) and a low detection limit (IC15, 0.01 μg L−1) for RAC under the optimum conditions, and it was applied to the determination of RAC in urine and pork samples spiked at
three levels with recoveries ranging from 77.7% to 108.9% (urine) and from 93.5% to 101.1% (pork). The obtained results, which
correlated well with those gained from the traditional high performance liquid chromatography (HPLC) method, demonstrated
that the developed ELISA method was reliable for RAC determination in real samples. 相似文献
13.
Statistical evaluation of fermentation conditions and nutritional factors by Plackett–Burman two-level factorial design followed
by optimization of significant parameters using response surface methodology for lipase production by Bacillus brevis was performed in submerged batch fermentation. Temperature, glucose, and olive oil were found to be the significant factors
affecting lipase production. Maximum lipase activity of 5.1 U ml−1 and cell mass of 1.82 g l−1 at 32 h were obtained at the optimized conditions of temperature, 33.7 °C; initial pH, 8; and speed of agitation, 100 rpm,
with the medium components: olive oil, 13.73 ml l−1; glucose, 13.98 g l−1; peptone, 2 g l−1; Tween 80, 5 ml l−1; NaCl, 5 g l−1; CH3COONa, 5 g l−1; KCl, 2 g l−1; CaCl2·2H2O, 1 g l−1; MnSO4·H2O, 0.5 g l−1; FeSO4·7H2O, 0.1 g l−1; and MgSO4·7H2O, 0.01 g l−1. The lipase productivity and specific lipase activity were found to be 0.106 U (ml h)−1 and 2.55 U mg−1, respectively. Unstructured kinetic models and artificial neural network models were used to describe the lipase fermentation.
The kinetic analysis of the lipase fermentation by B. brevis shows that lipase is a growth-associated product. 相似文献
14.
Wagner F. Pacheco Adriana Doyle Diego R. A. Duarte Cabrini S. Ferraz Pércio A. M. Farias Ricardo Queiroz Aucelio 《Food Analytical Methods》2010,3(3):205-210
Square-wave voltammetry was used for trace determination of azoxystrobin and dimoxystrobin in potatoes, grapes, and grape
juice. Experimental conditions have been optimized to achieve simultaneous determination of these analytes using the hanging
mercury drop electrode. Supporting electrolyte was HCl 0.1 mol L−1, and other optimized conditions were deposition potential (−300 mV), deposition time (30 s), amplitude (150 mV), frequency
(150 Hz), and step height (2 mV). Azoxystrobin and dimoxystrobin redissolution peaks presented their maxima, respectively,
at −928 mV and around −650 mV. Linear and homoscedastic analytical responses (r
2 > 0.99) have been observed. Limits of quantification as low as 119 μg L−1 (in grape juice) and 45 μg kg−1 (in potatoes and grapes) were found. A previous solid-phase extraction was necessary to eliminate interferences from potato
and grape samples. For grape juice, no sample treatment was required. Satisfactory recoveries (from 72.3% to 96.7% for dimoxystrobin
and from 81.7% to 102.3% for azoxystrobin) were found. Interferences from other strobilurins (piraclostrobin and picoxystrobin)
were evaluated. 相似文献
15.
Fatima Bisbal Jose Vicente Gil Daniel Ramón Pedro Vicente Martínez-Culebras 《European Food Research and Technology》2009,229(5):751-755
In the present study, ochratoxigenic mycobiota in cocoa beans was identified at species level by digestion of the ITS products
using the endonucleases HhaI, NlaIII and RsaI. Of the 132 isolates of Aspergillus section Nigri collected from cocoa beans, 89 were identified as A. tubingensis, 27 as A. niger, 10 as A. tubingensis-like and 6 as A. carbonarius. No variation was observed between RFLP patterns (C, N, T1 and T2) described previously for grape isolates and those of the
cocoa isolates analysed. With respect to OTA-producing fungi, a high percentage of black aspergilli (50.7%) was able to produce
OTA. Additionally, most of the OTA-producing isolates were of moderate toxigenicity, producing amounts of OTA from 10 μg g−1 to 100 μg g−1. Percentages of OTA-producing isolates in the A. niger aggregate were higher than in other substrates, ranging from 30% to 51.7%. Furthermore, the detected levels of OTA production
in the A. niger aggregate, particularly in A. tubingensis species was higher than in A. carbonarius, ranging from 0.7 μg g−1 to 120 μg g−1 (mean 24.55 μg g−1). Due to the high occurrence, percentage of ocratoxigenic isolates and their ability to produce OTA, isolates belonging to
the A. niger aggregate could be considered as the main cause of OTA contamination in cocoa beans used for manufacturing cocoa products. 相似文献
16.
Ultrasonically assisted extraction (UAE) followed by high performance liquid chromatography (HPLC) analysis method for the
fast extraction and determination of rutin in Artemisia selengensis Turcz has been developed. Artemisia selengensis Turcz has been used as food and herbal medicine for thousands of years in China. Rutin is one of the main active ingredients
of this plant. The extraction of rutin from Artemisia selengensis Turcz was investigated by UAE. Special emphasis has been given to optimize the extraction conditions which were those with
90:10 (v/v) methanol–ethanol as solvent, 30:1 liquid–solid ratio, and 40 min extraction time. In order to show the superiority of UAE,
other extractions were investigated, including microwave-assisted extraction, reflux extraction, and marinated extraction.
The results showed that UAE was most suitable for the extraction of rutin in Artemisia selengensis Turcz because of its high extraction efficiency. Reversed phase-HPLC with ultraviolet detection was employed for the analysis
of rutin in Artemisia selengensis Turcz. Under the optimum conditions, the calibration curve for the analyte was linear in the range of 0.34–20.7 μg mL−1. The mean recovery of rutin was 100.77%, and its relative standard deviation was 0.37% (n = 5). Three kinds of Artemisia selengensis Turcz from different habitats were investigated. The total content of rutin was 9.90, 6.23, 5.56 mg g−1, respectively. 相似文献
17.
Determination of 20 Free Amino Acids in Asparagus Tin by High-Performance Liquid Chromatographic Method after Pre-Column Derivatization 总被引:2,自引:0,他引:2
Weihua Li Meijun Hou Yongsong Cao Huan Song Tianyu Shi Xiwu Gao Daning Wang 《Food Analytical Methods》2012,5(1):62-68
A novel method was studied for determination of 20 free amino acids in asparagus tin by high-performance liquid chromatography
with pre-column derivatization. Derivatization of the samples was performed with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF),
and the SPE cartridge was used for purification and enrichment of the analytes. The derivatization conditions and the influence
of elution composition on the separation were investigated. The reaction of amino acids with CNBF was completed in pH 9.0
borate buffer. The separation of amino acids was achieved at room temperature within 60 min by gradient elution mode with
triethylamine in mobile phase, and the flow rate is 0.32 mL min−1 constantly. The method correlation coefficient was from 0.9975 to 1.0000 in concentrations ranging from 20 to 2000 μmol L−1, except asparagine (from 100 to 10000 μmol L−1). The detection limits of amino acids were from 1.2 to 6.0 μmol L−1, with a signal-to-noise ratio of three times. The calculated recoveries of the proposed method were from 81.4% to 109.4%,
and relative standard deviations were 0.48–3.94% in application to the quantitative determination of free amino acids in asparagus
tin samples. The present method is reliable and sensitive that allows fast analysis of free amino acids in asparagus tin,
which makes it suitable for further study of free amino acids in other asparagus foods. 相似文献
18.
Abayomi P. Adebiyi Ayobamitale O. Adebiyi Yusuke Hasegawa Tomohisa Ogawa Koji Muramoto 《European Food Research and Technology》2009,228(3):391-401
Rice bran contains underutilised protein materials. Sequential extraction of rice bran protein (RBP) from defatted rice bran
was conducted based on the differences in their solubility. Three extraction methods were investigated. Method 1 involved
the isoelectric and acetone precipitation using water, 50 g kg−1 NaCl, 0.02 mol L−1 NaOH and 70% ethanol as extracting solvents for albumin (pH 4.1), globulin (pH 4.3), glutelin (pH 4.8) and prolamin, respectively.
Method 2 adopted dialysis and sequential extraction was carried out with 20 g kg−1 NaCl, 70% ethanol, 0.1 mol L−1 acetic acid and 0.1 mol L−1 NaOH solution as extracting solvents. Method 3 combined dialysis, isoelectric and acetone precipitation for the extraction.
Based on the yields and data obtained from sodium dodecyl sulphate polyacrylamide gel electrophoresis, size-exclusion chromatography
and differential scanning calorimetry, method 3 was chosen for the isolation and characterization of RBPs. Rice bran protein
fraction (RBPF)—albumin, globulin, glutelin and prolamin were obtained in good yields. Denaturation temperature and enthalpy
values of denaturation of RBPF vary. Highest phytate content was found in albumin and lowest in prolamin. The highest antioxidative
and hemagglutinating activities were observed in albumin. 相似文献
19.
Hanwen Sun Zhansheng Kang Hui Li Jingxuan Zhang Yunkai Lv 《Food Analytical Methods》2012,5(4):643-650
A new method for multi-residue determination of five synthetic glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, and hydrocortisone) in milk powder is developed. The glucocorticoids in the samples were extracted with tert-butyl methyl ether under ultrasonication incubation, and then cleaned up through gel permeation chromatography. After C18 LC gradient elution separation using acetonitrile with 0.1% formic acid as a mobile phase, the eluents were determined by liquid chromatography–tandem mass spectrometry with multiple reaction monitoring and positive ionization modes. The effective separation for the five glucocorticoids was achieved. The limit of quantification of the method for testing five glucocorticoids in milk powder was in the range from 0.2 to 0.5 μg kg−1, which was lower than the maximum residue limits established by European Union for glucocorticoids in foods. Experiments on spiked samples of milk powder showed that the mean recoveries at addition level of 1.0, 3.0, and 5.0 μg kg−1 were in the range of 71.2% and 103%, and the relative standard deviation ranged from 4.7% to 16.8%. The calibration curves for these drugs between 1.0 and 100 μg l−1 showed good linearity, with correlation coefficient (r) more than 0.999. The real sample test showed that this method is sensitive and accurate. It can be used for qualitative and quantitative determination of studied glucocorticoid residues in milk powder samples. 相似文献
20.
Effect of dynamic high-pressure microfluidization at different temperatures on the antigenic response of bovine β-lactoglobulin 总被引:4,自引:0,他引:4
Junzhen Zhong Chengmei Liu Wei Liu Xiaofei Cai Zongcai Tu Jie Wan 《European Food Research and Technology》2011,233(1):95-102
The antigenic response of β-lactoglobulin (β-Lg), treated by dynamic high-pressure microfluidization (DHPM) at different temperatures,
was determined by an indirect competitive enzyme-linked immunosorbent assay using polyclonal antibodies from rabbit serum.
DHPM treatment causes changes in the protein structure and may influence the antigenicity of β-Lg. DHPM treatment of β-Lg
at 90 °C showed significant effects with the antigenic response of 5.2 μg mL−1 (untreated), 45 μg mL−1 (40 MPa), 79 μg mL−1 (80 MPa), 132 μg mL−1 (120 MPa), and 158 μg mL−1 (160 MPa). In combination with temperature treatment (70–90 °C), the antigenic response enhanced as the temperature increased
at 160 MPa. The β-Lg antigenicities were about 14, 108, and 158 μg mL−1 at 70, 80, and 90 °C, respectively. However, the influence of DHPM pressures on the antigenic response of β-Lg standards
was different. DHPM modified β-Lg standards showed a remarkable increase in antigenicity when treated to 80 MPa. Above 80 MPa,
the antigenic response decreased. 相似文献