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1.
Dietary α-Tocopheryl Acetate Contributes to Lipid Stability in Cooked Beef   总被引:1,自引:1,他引:0  
Lipid oxidation was investigated in cooked gluteus medius from Holstein steers fed diets including four levels of α-tocopheryl acetate (0, 250, 500 and 2,000 mg/steer daily) for 42 or 126 days. Alpha-tocopherol (vitamin E) concentrations increased in fresh and cooked muscle due to level and duration of supplementation (P<0.01). Cooking did not affect α-tocopherol concentration in the muscle. Dietary α-tocopheryl acetate delayed (P<0.01) accumulation of lipid oxidation products in cooked muscle during 6 days of display at 4°. Daily supplementation of 500 mg α-tocopheryl acetate for 126 days resulted in 3.4 μg α-tocopherol/g cooked gluteus medius.  相似文献   

2.
The objective of this experiment was to determine whether source of supplemental α-tocopherol fed to periparturient dairy cows affects neutrophil function and vitamin E status of the cow and the neonatal calf. Starting 14 d before anticipated calving and continuing until 14 d post-parturition, cows were fed diets with no supplemental vitamin E or with 2,500 IU/d of vitamin E from all-rac α-tocopheryl acetate or RRR α-tocopheryl acetate. All-rac α-tocopherol contains equimolar amounts of all 8 stereoisomers, whereas the RRR contains only the RRR isomer. Concentrations of α-tocopherol in cow plasma, colostrum, milk, and blood neutrophils were greatest for the RRR treatment, intermediate for all-rac, and lowest for cows fed no supplemental vitamin E. The concentration of α-tocopherol in plasma of newborn calves was very low and not affected by treatment but after 6 feedings of their dam's colostrum or milk, concentrations in calf plasma followed the same treatment pattern as cow plasma. The number of bacteria phagocytized was greater by neutrophils from cows fed all-rac vitamin E than for the other 2 treatments, which resulted in a greater number of bacteria being killed. For cows fed all-rac vitamin E, the RRR isomer comprised about 20% of the α-tocopherol consumed but approximately 60% of the α-tocopherol in plasma and milk. This enrichment was caused mostly by an almost complete discrimination against the 2S isomers. Because all-rac α-tocopherol is 50% 2S isomers, these data suggest that 1 g of all-rac tocopheryl acetate is equivalent to 0.5 g of RRR tocopheryl acetate.  相似文献   

3.
A simple, precise, accurate, and validated reverse-phase HPLC method was developed for the determination of melamine in milk (pasteurized and UHT milk) and dairy products (powdered infant formula, fruit yogurt, soft cheese, and milk powder). Following extraction with acetonitrile:water (50:50, vol/vol), samples were purified by filter (0.45 μm), separated on a Nucleosil C8 column (4.6 mm × 250 mm, 3 μm) with acetonitrile:10 mmol/L sodium L-octane sulfonate (pH 3.1; 15:85, vol/vol) as mobile phase at a flow rate of 1 mL/min, and determined by a photodiode array detector. A linear calibration curve was obtained in the concentration range from 0.05 to 5 mg/kg. Milk and dairy products were fortified with melamine at 4 levels producing average recovery yields of 95 to 109%. The limits of detection and quantification of melamine were 35 to 110 and 105 to 340 μg/kg, respectively. The method was then used to analyze 300 samples of milk and dairy products purchased from major retailers in Turkey. Melamine was not found in infant formulas and pasteurized UHT milk, whereas 2% of cheese, 8% of milk powder, and 44% of yogurt samples contained melamine at the 121, 694±146, and 294±98 μg/kg levels, respectively. These findings were below the limits set by the Codex Alimentarius Commission and European Union legislation. This is the first study to confirm the existence of melamine in milk and dairy products in Turkey. Consumption of foods containing these low levels of melamine does not constitute a health risk for consumers.  相似文献   

4.
开发了一种快速测定婴幼儿乳粉中α-生育酚以及α-生育酚醋酸酯的正相高效液相色谱法。使用乙醇、正己烷提取,40℃下等度洗脱;流动相是体积比为97.2:2.8的正己烷-乙酸乙酯混合溶剂,流速为0.5 mL/min;α-生育酚和α-生育酚醋酸酯的检测波长分别为284 nm和296 nm。结果表明:α-生育酚和α-生育酚醋酸酯的回收率分别为99.41%,102.17%;多次测定相对标准偏差分别为3.45%和3.27%。检出限分别为5.5ng,6.9ng。本方法操作简单、精密度、回收率和灵敏度高,适用于快速检测婴幼儿奶粉中α-生育酚以及α-生育酚醋酸酯。  相似文献   

5.
The effect of feeding high levels of α-tocopherol to pigs on the susceptibility to oxidative deterioration and weight loss in dry cured hams was investigated. The α-tocopherol concentration in thigh muscle from pigs fed the basal and the supplemented diet (200 mg kg(-1) α-tocopheryl acetate) in unprocessed thighs was 8.69 and 16.87, μg g(-1) dry matter, not including ash, respectively (p-value=0.015), while the concentration was 6.65 and 14.28 μg g(-1), respectively, in the final products (p-value=0.011). Hams from pigs fed the basal diet oxidized more during storage (p-value=0.015) as measured by formation in thiobarbituric acid reactive substances and had a higher rate of weight loss (p-value=0.0001). The total loss in red color after 4 days of storage was similar in all treatments. However, the rate of discoloration was more pronounced during the first 2 days of storage in hams from pigs fed the basal diet (p-value=0.016). This result indicates that high dietary level of α-tocopheryl acetate to pigs increases the oxidative stability in dry cured hams manufactured on the basis of such pigs.  相似文献   

6.
Rainbow trout (Oncorhynchus mykiss) were fed diets supplemented with canthaxanthin, oleoresin paprika and α-tocopherol. Canthaxanthin was more efficiently absorbed (3.8–7.9 mg/kg) in the flesh of rainbow trout than the paprika carotenoids (2.4–3.1 mg/kg). With increased pigmentation, decrease in lightness (L*) and hue angle, and increase in redness (a*) of the muscle were observed. Canthaxanthin produced more desirable reddish-pink color. Deposition of α-tocopherol in liver and muscle tissue increased with increase in dietary α-tocopheryl acetate. Fish receiving lower α-tocopheryl acetate reached maximum deposition levels earlier than those fed higher levels. There was no effect of α-tocopherol and carotenoid levels on muscle fatty acid composition.  相似文献   

7.
The effect of feeding supra-nutritional levels of α-tocopheryl acetate on its deposition in two porcine muscles of different metabolic rates (m. longissimus dorsi and m. psoas major) and the effect on meat quality (lipid oxidation, colour stability and drip loss) was studied. Pigs were fed a standard diet supplemented with three levels: 100, 200 and 700 mg/kg of α-tocopheryl acetate from the time of weaning to slaughter at 90kg live weight. Muscle α-tocopherol levels were linearly related to the logarithm of dietary α-tocopheryl acetate supplementation and the linear relationship was estimated for the two muscles. The levels of α-tocopherol in the two muscles differed by a parallel displacement with consistently higher α-tocopherol levels in m. psoas major compared to m. longissimus dorsi. Dietary α-tocopheryl acetate supplementation significantly reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS) in both raw and cooked meat during storage at 4 °C for 6 days. Drip loss and colour stability of raw muscles were not affected by dietary α-tocopheryl acetate levels, 100mg α-tocopheryl acetate/ kg feed resulted in sufficient α-tocopherol levels in muscles to ensure minimum drip loss and optimum colour stability.  相似文献   

8.
Concentrations of retinol, α-tocopherol, and major carotenoids in dairy products are often determined simultaneously by liquid chromatography. These compounds have different polarity and solubility; thus, extracting them simultaneously can be difficult and inefficient. In milks with low carotenoid concentrations, the xanthophylls lutein and zeaxanthin may not be completely resolved using common extraction techniques. A simplified method was developed to optimize extraction efficiency and the limit of detection and limit of quantification (LoQ) of lutein and zeaxanthin in bovine milk without decreasing sensitivity to other vitamins or carotenoids. The developed method evaluates lutein, zeaxanthin, β-carotene, retinol, and α-tocopherol simultaneously by ultra-high performance liquid chromatography–photodiode array detection. Common saponification temperatures (40–60°C) and concentrations of KOH in water (10–50% KOH wt/vol) were evaluated. Multiple solvents were evaluated for optimal xanthophyll extraction (diethyl ether, dichloromethane, hexane, and tetrahydrofuran) following saponification. The limit of detection and LoQ were defined as 3:1 and 10:1 signal-to-noise ratio, respectively. All experiments were performed in triplicate. The optimal saponification procedure was a concentration of 25% KOH at either 40 or 50°C. Saponified extracts solubilized in solutions containing diethyl ether had greater concentrations of lutein- than hexane- or tetrahydrofuran-based solutions, with peak areas above LoQ values. The solution containing diethyl ether solubilized similar concentrations of retinol, α-tocopherol, and β-carotene when compared with other solutions. The proposed optimized method allows for the simultaneous determination of carotenoids from milk with increased lutein and zeaxanthin sensitivity without sacrificing recovery of retinol, α-tocopherol, and β-carotene.  相似文献   

9.
《Food chemistry》1998,62(2):185-190
The effects of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg α-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0kGy. Cooked irradiated and unirradiated meat was stored at 4 °C for 5 days. α-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary α-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg α-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg α-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in α-tocopherol-supplemented meat following cooking and storage.  相似文献   

10.
A simple, sensitive and accurate HPLC method has been developed and validated for the simultaneous determination of α-tocopherol, γ-tocopherol, δ-tocopherol, α-tocopheryl acetate, retinyl palmitate, retinol and β-carotene in milk- and soy-juice based beverages. The assay was performed using a Luna RP-C18 column with methanol: THF: water (67:27:6, v/v/v) as mobile phase, at a flow rate of 0.8 mL/min. Diode-array detector was set at 290 nm for tocopherols, 325 nm for retinols and 440 nm for β-carotene. The method developed and validated is simple and shows good linearity, precision, accuracy and sensitivity and was applied to the analysis of different commercial mixed beverages. The profile of these compounds was different in milk- or soy-juice. Tocopheryl acetate and retinyl palmitate are added in all milk-juice and free γ- and δ-tocopherols are characteristic of soy-juice samples. β-carotene is present in both types of mixed beverages.  相似文献   

11.
高效液相色谱法测定肉松中的淀粉含量   总被引:1,自引:0,他引:1  
建立超声辅助双酶水解法联合高效液相色谱测定肉松制品中淀粉含量的检测方法。采用超声辅助双酶水解法水解肉松中的淀粉后,利用高效液相色谱法对水解液中的葡萄糖含量进行测定,并换算为淀粉含量,采用C18色谱柱(4.6?mm×250?mm,5?μm),以乙腈-20?mmol/L乙酸铵溶液(22∶78,V/V)为流动相,以245?nm为分析波长,葡萄糖在5~50?mg/L质量浓度范围内线性良好,相关系数r大于0.999。本实验采用耐高温α-淀粉酶与淀粉葡萄糖苷酶酶解淀粉,该方法仪器检出限为0.4?μg/mL,方法检出限为0.16%。通过肉松水解液加标验证,平均回收率为88.0%~96.6%,相对标准偏差小于5%(n=6)。与国家标准方法相比,该方法重复性好、回收率高,适用于各种肉松中淀粉含量的测定。?  相似文献   

12.
The ruminal fate of the fat-soluble vitamins D and E was studied in dairy cows. Ten to 15 kg of ruminal contents was taken from each cow through a ruminal fistula. A sample was taken out (0-h sample) and the rest of the contents were mixed with 4,360 mg of all-rac-α-tocopheryl acetate (vitamin E; study 1) or 4,360 mg of all-rac-α-tocopheryl acetate, 250 mg of ergocalciferol (vitamin D2), and 250 mg of cholecalciferol (vitamin D3; study 2). After mixing, the ruminal contents were returned to the respective cows. Blood was collected 0, 6, 24, and 30 h after introducing the vitamins into the rumen. Samples of ruminal contents were collected at 0, 1, 2, 4, 6, 24, and 30 h (in vivo). From the 1-h sample, 6 subsamples from each cow were incubated at 37°C and taken out at 2, 4, 6, 12, 24, and 30 h (in vitro). In vivo concentrations of added α-tocopherol, ergocalciferol, and cholecalciferol in the rumen first increased and subsequently declined due to dilution effects of eating and passage out of the rumen. The level of the free-alcohol form of α-tocopherol from the natural content in feed was constant throughout the in vivo study, in contrast to the content of total α-tocopherol, which indicated that no hydrolysis of the acetate form into alcohol form happened in the rumen. In vitro, all added vitamins were found at constant levels; hence, none of the added vitamins were degraded in ruminal contents. The concentration of α-tocopherol in plasma increased at a rate per milligram of ruminally introduced α-tocopherol below the rate of the increase in plasma ergocalciferol or cholecalciferol metabolites per milligram of introduced ergocalciferol or cholecalciferol, respectively, over 24 h. In conclusion, ergocalciferol, cholecalciferol, and α-tocopheryl acetate proved to be stable in the rumen and in ruminal contents from high-yielding dairy cows. Changes in plasma concentrations of the vitamins relative to the amount of vitamin introduced to the rumen indicated a lower effect on plasma status of ergocalciferol than of cholecalciferol, and an even lower effect of α-tocopherol. The limited plasma response after a single dose of α-tocopheryl acetate led to the conclusion that oral single dose therapy with all-rac-α-tocopheryl acetate is of limited physiological value.  相似文献   

13.
The effects of vitamin E (all-rac-α-tocopheryl acetate) supplementation on meat color and oxidative stability of muscle lipids in New Zealand White rabbits was determined. Twenty animals received pelleted diet (containing 60 mg/kg α-tocopheryl acetate) and 10 of these (treatment group) received drinking water containing 100 mg α-tocopheryl acetate/L for 15 days before slaughter. The α-tocopherol content of the longissimus lumborum muscle (LL) was higher (5.66 vs 1.65 μg/g) in the supplemented group than the control group (p<0.001). The surface redness (a*) of the muscle showed a significant time×treatment effect (p<0.001), decreasing more in the control group over 11 days of storage in the dark at +2.5°C. The lightness (L*) showed a tendency (p=0.06) for a treatment×time effect. No effect of vitamin supplementation was observed on yellowness (b*). Thiobarbituric acid reactive substances (TBARS) in muscle, an index of oxidative stability, were lower in the treated than control group throughout storage (p<0.01 for treatment effect). Vitamin E supplementation appears to be an effective way to improve the color and lipid stability of rabbit meat.  相似文献   

14.
The effect of dietary α-tocopheryl acetate supplementation on the uptake of α-tocopherol in ewe plasma, lamb plasma, milk, organs and muscles was investigated. The oxidative stability and colour in fresh M. longissimus dorsi and frozen M. longissimus dorsi, M. psoas major and M. gluteus medius were also investigated. Ewes (n = 12) were selected and scanned to assess pregnancy. They were divided into two groups (n = 6). The control group was fed a diet containing 20 mg α-tocopheryl acetate/kg feed/day and the supplemented group fed a diet containing 1000 mg α-tocopheryl acetate/kg feed/day, for 9 weeks ante-parturition and 3 weeks post-parturition. The lambs were weaned at 3 weeks and fed supplemented or basal feed for 10 weeks before slaughter. Plasma α-tocopherol increased significantly (p < 0.01) in ewes in the 9 weeks ante-parturition, and lamb plasma taken just before slaughter was significantly (p < 0.01) higher for the supplemented group than the basal group, following 13 weeks of supplementation. Milk α-tocopherol levels were significantly (p < 0.01) higher from ewes fed the supplemented diet at parturition and for the three weeks of supplementation post-parturition (p < 0.05). Supplementation increased the α-tocopherol levels in all tissues sampled. The α-tocopherol concentrations in M. longissimus dorsi and M. psoas major were also determined after frozen storage at -20 °C for 34 weeks. Frozen storage resulted in a significant (p < 0.01) reduction in mean α-tocopherol levels for M. longissimus dorsi but not M. psoas major. Dietary supplementation with α-tocopheryl acetate significantly (p < 0.05) increased the oxidative stability of lamb muscle. Surface colour (Hunter L, a, b) was found to be negatively correlated with metmyoglobin content. Supplementation reduced surface discolouration in refrigerated display under fluorescent light over a 6-7 day storage period. The effect was more pronounced in frozen displayed muscles than in freshly displayed samples.  相似文献   

15.
建立了高效液相色谱-串联质谱同时测定马铃薯及马铃薯粉中α-茄碱与α-卡茄碱含量的方法。样品采用10%乙酸水溶液匀浆提取3 min,马铃薯粉提取液经Bond Elut C18 SPE柱净化后,采用C18色谱柱分离,液相色谱串联质谱仪检测。结果表明,α-茄碱和α-卡茄碱在0.01~1.00 μg/mL范围内线性关系良好,相关系数分别为0.9998和0.9997。马铃薯和马铃薯粉在低、中、高三个添加浓度范围内,回收率在90.0%~110%之间,相对标准偏差在1.6%~5.0%之间。马铃薯中α-茄碱和α-卡茄碱的定量限分别为0.80和0.42 μg/kg,马铃薯粉中α-茄碱和α-卡茄碱的定量限分别为25和14 μg/kg(S/N=10)。本方法简单快速,灵敏度高,重复性好,适用于马铃薯及马铃薯粉中的α-茄碱和α-卡茄碱检测。  相似文献   

16.
A fast and easy-to-use confirmatory liquid-chromatography tandem mass-spectrometry (LC-MS/MS) based-method was developed for the analysis of the pesticide sodium monofluoroacetate (MFA, also called “1080”) in infant formulas and related dairy products. Extraction of the compound encompassed sample reconstitution and liquid–liquid extraction under acidic conditions. Time-consuming solid-phase extraction steps for clean-up and enrichment and tedious derivatisation were thus avoided. Resulting sample extracts were analysed by electrospray ionisation (ESI) in negative mode. Quantification was performed by the isotopic dilution approach using 13C-labelled MFA as internal standard. The procedure was validated according to the European document SANCO/12571/2013 and performance parameters such as linearity (r2 > 0.99), precision (RSD(r) ≤ 9%, RSD(iR) ≤ 11%) and recovery (96–117%) fulfilled its requirements. Limit of quantifications (LOQ) was 1 µg kg?1 for infant formulas and related dairy products except for whey proteins powders with a LOQ of 5 µg kg?1. Method ruggedness was further assessed in another laboratory devoted to routine testing for quality control.  相似文献   

17.
吴映璇  林峰  陈思敏 《食品科学》2019,40(10):325-330
建立测定乳制品中莫奈太尔及其代谢物的高效液相色谱-串联质谱法。试样加水-饱和氯化钠-乙腈溶液提取,正己烷净化,经Inertsil C8(2.1 mm×100 mm,3 μm)色谱柱分离,以甲醇-0.5 mmol/L乙酸铵溶液为流动相进行梯度洗脱,采用电喷雾离子源串联质谱,在负离子扫描方式下以多反应监测模式检测,外标法定量。结果表明:莫奈太尔及其代谢物在0.1~5.0 μg/L范围内线性关系良好,定量限为2.0 μg/kg。在3 个加标水平下的平均回收率为79.5%~102.9%,相对标准偏差为2.0%~5.3%。该方法操作简便、快速、准确、灵敏度高、抗干扰能力强、回收率和重复性良好,适合于乳制品中莫奈太尔及其代谢物的测定。  相似文献   

18.
A sensitive and selective isotope dilution ion chromatography/tandem mass spectrometry (ID IC-MS/MS) method was developed and validated for the determination of perchlorate in infant formula. The perchlorate was extracted from infant formula by using 20 ml of methanol and 5 ml of 1% acetic acid. All samples were spiked with (18)O(4) isotope-labelled perchlorate internal standard prior to extraction. After purification on a graphitised carbon solid-phase extraction column, the extracts were injected into an ion chromatography system equipped with an Ionpac AS20 column for separation of perchlorate from other anions. The presence of perchlorate in samples was quantified by isotope dilution mass spectrometry. Analysis of both perchlorate and its isotope-labelled internal standard was carried out on a Waters Quattro Ultima triple quadrupole mass spectrometer operating in a multiple reaction monitoring (MRM) negative ionisation mode. The method was validated for linearity and range, accuracy, precision, sensitivity, and matrix effects. The limit of quantification (LOQ) was 0.4 μg l(-1) for liquid infant formula and 0.95 μg kg(-1) for powdered infant formula. The recovery ranged from 94% to 110% with an average of 98%. This method was used to analyse 39 infant formula, and perchlorate concentrations ranging from 相似文献   

19.
ABSTRACT: The effect of feeding laying hens linseed oil or sunflower oil, with and without α-tocopheryl acetate and/or canthaxanthin, was evaluated on cholesterol oxidation in spray-dried whole egg at various storage periods. Storage of spray-dried eggs at room temperature in the dark resulted in an increase in cholesterol oxidation products from 18.1 μg/g, after spray drying, to 39.3 μg/g, at 12 mo of storage. No differences were found with either dietary oil or canthaxanthin supplementation. However, α-tocopheryl acetate supplementation resulted in a lower formation of cholesterol oxidation products during storage. No synergistic effect between α-tocopherol and canthaxanthin was detected.  相似文献   

20.
《Journal of dairy science》2022,105(11):8839-8849
Little is known about transfer of dietary β-carotene into colostrum, its absorption by the calf, and its effects on retinol and α-tocopherol in the calf when the dam's dietary vitamin A is adequate. Our objective was to assess the effect of β-carotene supplementation during the close-up dry period on the colostrum and calf. The study was conducted on a large commercial dairy farm in Indiana during early summer of 2015. Ninety-four multiparous Holstein cows were blocked by calving data, parity, and previous production, and then randomly assigned to either control or β-carotene (BC) treatments. While locked in headgates each morning, each cow received a topdress of β-carotene (Rovimix, DSM Nutritional Products, 8 g/d; provided 800 mg β-carotene) or carrier from 21 d before expected calving until calving. Colostrum was collected within 2 h of parturition. Calf blood samples were obtained within 2 h of birth before receiving the dam's colostrum, at 24 h after birth, and at 7 d and 60 d of age. Blood serum was analyzed for β-carotene, retinol, α-tocopherol, and other metabolites and enzymes. Colostrum was analyzed for β-carotene, retinol, α-tocopherol, colorimetry profile, and milk components. Data were analyzed using mixed-effects models in SAS (SAS Institute Inc.). Calf serum β-carotene data were analyzed using the FREQ procedure. Colostrum β-carotene was higher for BC cows. Colostrum from BC cows had increased a* [measures red (positive) to green (negative)] and b* [measures yellow (positive) to blue (negative)] colorimeter values, indicating that β-carotene altered colostrum color toward red and yellow. Supplementation did not affect colostral or calf IgG concentrations. Colostrum color indices were correlated with IgG concentrations as well as concentrations of β-carotene, retinol, and α-tocopherol. Before receiving colostrum, the concentration of β-carotene in calf serum was below the detectable threshold of 0.05 μg/mL. At 24 h of age, the number of calves with detectable β-carotene concentrations increased, with more calves from BC cows (52.1%) having detectable concentrations than calves from cows in the control group (6.1%). No differences in concentrations of retinol or α-tocopherol were observed in calf serum. Supplementation of β-carotene to cows decreased activities of gamma-glutamyl transpeptidase and glutamate dehydrogenase in calf serum. In pregnant cows already receiving adequate vitamin A, supplementation of β-carotene increased concentration of β-carotene in colostrum, altered colostrum color, and increased serum β-carotene in calves at birth.  相似文献   

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