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1.
本文以稀HCl从蚕粉中提取1-脱氧野尻霉素（1-deoxynojirimycin,1-DNJ）,通过单因素试验确定提取影响因素的水平,并采用响应面法研究料液比分数、浸提温度和浸提时间对蚕粉1-DNJ提取工艺的影响。其中1-DNJ含量测定采用9-芴基氯甲酸甲酯（FMOC-Cl）衍生化法,并用反相高效液相色谱对其衍生物进行测定。1-DNJ高效液相色谱检测谱图表明,通过液相色谱荧光可以检测蚕粉来源的1-DNJ。响应面优化实验结果表明,1-DNJ的最佳提取条件为：提取时间3.3h,浸提温度72.9℃,料液比分数为1：282。在此条件下,1-DNJ的理论提取率为0.493%,实际提取率为0.487%,相对误差为1.2%。本研究初步建立了稀酸浸提家蚕1-DNJ的二次多项数学模型,确定其最佳提取工艺条件,为工业化生产提供参考。 相似文献
2.
Siret R Boursiquot JM Merle MH Cabanis JC This P 《Journal of agricultural and food chemistry》2000,48(10):5035-5040
In an attempt to develop a technique for the identification of grape cultivars in commercial wines, a method for the extraction of DNA from must and experimental wines was adapted and optimal PCR conditions for the amplification of this DNA were established. DNA was analyzed during the fermentation process for six cultivars (Chardonnay, Clairette blanche, Grenache noir, Merlot, Muscat blanc à petits grains, and Syrah). The extractions were performed on solid parts in suspension as well as on the aqueous fraction. Expected profiles for these cultivars were obtained with DNA extracted from the solid parts during all of the fermentation process and for the wine. The analysis of DNA extracted from aqueous fractions was less reproducible, and microsatellite amplifications were obtained only in the case of Clairette blanche, Merlot, and Syrah wines. Results demonstrate that the purification process is adequate for the analysis but that the DNA concentration represents the main limiting factor. Technical improvements of the method are discussed. 相似文献
3.
The total petroleum hydrocarbon (TPH) extraction potential of organic solvents including dichloromethane (DCM), pentane, hexane, methanol, ethanol, propanol, and acetone was investigated along with the effect of water content in solvents for their efficiency of extraction. The extent of TPH extraction was analyzed using various extraction schemes (i.e., solvent/solid ratio, treatment time, extraction method, solvent/water ratio) to better understand the physical and chemical factors controlling TPH release from contaminated soils. More TPH was extracted with increasing solvent/solid ratio and increasing time. The extent of TPH extracted also varied depending on the extraction method, solvent type, and solvent/water ratio, but was highest when using the total extraction method and 100% DCM. However, the efficiency of TPH extraction decreased dramatically with the increase in the water content in organic solvents. The results also showed that TPH extraction using DCM was the best option for achieving cost-effective, eco-friendly outcomes along with remediation goals. DCM used in solvent extraction to remediate diesel-contaminated soils showed low toxicity, low cost, high recycling potential, and high efficiency compared to the other solvents tested in this study. 相似文献
4.
A new device that allows extraction of volatiles from solid materials by SPME, avoiding preparation of the sample, was designed and tested in two different food products. Volatiles from dry-cured ham and canned liver sausage were analyzed by headspace SPME (HS SPME) and by using a new device that protects the SPME fiber in the core of the solid material. Volatile profiles generated by using both methods of extraction were very similar in both products. Compounds that have been previously highlighted as quality markers, such as products from oxidative degradation of lipids, products from Strecker degradation of amino acids, or terpenes, were satisfactorily extracted by SPME coupled to the device for direct extraction. In addition, by using this method no laboratory contaminants were extracted, whereas some major laboratory solvents were presented in the chromatogram using the HS SPME method. However, coefficients of variation were higher when performing the direct sampling procedure. This new device appears to have potential as a simple method for extracting volatiles in solid materials while at the same time avoiding taking samples. 相似文献
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Aroma-active components in fermented bamboo shoots. 总被引：4，自引：0，他引：4
Shih-Guei Fu Youngmo Yoon Russell Bazemore 《Journal of agricultural and food chemistry》2002,50(3):549-554
Bamboo shoots (Phyllostachys pubescens) were fermented and prepared in a traditional Taiwanese manner. Static and dynamic headspace extractions of volatile compounds were conducted by solid phase microextraction (SPME) and by cryogenic focusing purge and trap, respectively. Volatile analysis was conducted with gas chromatography and mass spectrometry. Gas chromatography-olfactometry (GCO) was conducted utilizing the Osme time-intensity method. Of 70 volatile compounds detected, 29 possessed aroma activity, and the most odor active included p-cresol (barn-like), 2-heptanol (mushroom), acetic acid (vinegar), and 1-octen-3-ol (mushroom). SPME extracted 66 compounds, purge and trap extracted 14 compounds, and 12 compounds were common to both methods. The Osme GCO technique coupled with SPME is an effective tool for the extraction and evaluation of aroma-active headspace volatiles. 相似文献
8.
施用碱稳定固体的酸性土壤的Cu和Zn的形态分布 总被引：2，自引：1，他引：2
LUO Yong-Ming 《土壤圈》2002,12(2):165-170
Fractionation of metals in a granite-derived acid sandy loam soil amended with alkaline-stabilised sewagesIudge biosolids was conducted in order to assess metal bioavailability and environmental mobility soil solution was extracted by a centrifugation and filtration technique. Metal speciation in the soil solution wasdetermined by a cation exchange resin method. Acetic acid and EDTA extracting solutions were used forextraction of metals in soil solid surfaces. Metal distribution in different fractions of soil solid phase was determined using a three-step sequential extraction scheme. The results show that the metals in the soilsolution existed in different fractions with variable lability and metals in the soil solid phase were also presentin various chemical forms with potentially different bioavail ability and environmental mobility Alkaline-stabilised biosolids could elevate solubility of Cu and proportion of Cu in organically complexed fractionsboth in soil liquid and solid phases, and may therefore increase Cu mobility. In contrast, the biosolids lowered the concentrations of water-soluble Zn (labile fraction) and exchangeable Zn and may hence decrease bioavailability and mobility of Zn. However, Fe and Mn oxides bound and organic matter bound fractions are likely to be Zn pools in the sludge-amended soil. These consequences possibly result from the liming effect and metal speciation of the sludge product and the difference in the chemistry between the metals in soil. 相似文献
9.
Characterization of haze-active proteins in apple juice 总被引：8，自引：0，他引：8
The nature of the haze-active protein (HAP) in apple juice was investigated. Heat treatment removed protein indiscriminately while polyvinylpolypyrrolidone (PVPP) treatment was fairly specific for proteins of 15 and 28 kDa. Presumably, the PVPP bound to polyphenols, which in turn were complexed with protein. Three candidate apple HAPs were isolated. Two were extracted from juice with acetone and fractionated by hydrophobic interaction chromatography and solid phase extraction with C18 (HAP I) or SAX (HAP II) material. Hydroxyproline-rich protein was extracted from apple tissue (HAP III). The order of haze formation with tannic acid was gliadin > HAP III > HAP II > HAP I > bovine serum albumin, which shows increasing haze formation with increasing proline content. The sizes of HAP I, II, and III were 28, 15, and 12 kDa; the first two corresponded to the sizes of proteins removed by PVPP treatment and are involved in juice haze formation. 相似文献
10.
次生磷矿石表面的Ｃａ－Ｐ吸附层对磷矿石磷的释放有重要影响,以ＮａＣｌ,ＫＣｌ或ＮＨ４Ｃｌ浸提除去磷矿石表面的吸附态Ｃａ,导致了随后的水提取磷的大量增加。认为磷矿石表面的吸附层给磷灰石的加速溶解提供了Ｃａ的接收率。 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(17-18):3033-3041
Abstract Regeneration of a soil with a high degree of desertification was conducted by the addition of different doses of municipal solid waste organic matter (MSW). Five years after this treatment, humic substances were extracted from these soils and characterized by spectroscopy and isoelectric focusing. No significant differences between E4/E6 ratio and ?log K (Log A400 nm‐log A600 nm) were observed for humic substances extracted from treated and untreated soils. However, the isoelectric focusing (IEF) technique established differences between the humic substances from control and treated soils. The focusing pattern of the former showed a well defined band at pH 9.1 which nearly disappeared in the soils with high doses of MSW (1–2 %). However the organic matter which focused at pH 5.8 was present in all soils. 相似文献
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Dissolved organic carbon (DOC) and nitrogen (DON) are important components of the carbon and nitrogen turnover in soils. Little is known about the controls on the release of DOC and DON from forest floors, especially about the influence of solid phase properties. We investigated the spatial variation of the release of DOC and DON from Oe and Oa forest floor samples at a regional scale. Samples were taken from 12 different Norway spruce sites with varying solid phase properties, including C/N ratio, pH, different fractions of extractable carbon and exchangeable cations. Most of these solid phase properties are available for large forested areas of Europe in high spatial resolution. The samples were incubated at water holding capacity for eight weeks at 15°C and then extracted with an artificial throughfall solution to measure DOC and DON release. The rates of soil respiration and N-mineralization were determined to estimate soil microbial activity. The release of DOC and DON from Oe samples was two- to threefold higher than from Oa samples. The amounts released differed by one order of magnitude among the sites. The DOC/DON ratios in the percolates of the Oa samples were much higher as compared to the solid phase C/N, indicating different release rates of DOC and DON. In contrast, the DOC/DON ratios of the Oe percolates were in the range of the C/N ratios of the solid phase. The release of DOC and DON from Oe samples was not statistically correlated to any of the measured solid phase parameters, but to N-mineralization. The DOC and DON release from the Oa samples was positively related only to pH and soil respiration. Overall it was not possible to explain the large spatial variation of DOC and DON release by the measured solid phase properties with satisfying accuracy. 相似文献
13.
García-Beneytez E Moreno-Arribas MV Borrego J Polo MC Ibáñez J 《Journal of agricultural and food chemistry》2002,50(21):6090-6096
A DNA-based method has been applied to the identification of several musts and wines using microsatellite markers. DNA was extracted from the solid phases of sixteen monovarietal and five multivarietal musts (mixtures of two musts down to a 4:1 proportion) and they were genotyped at seven microsatellites through a multiplex PCR reaction and automated fluorescent detection. PCR multiplexing was successful in monovarietal musts, but should be used with caution with at least some markers and in multivarietal musts. The same extraction and detection methods were unsuccessfully applied to the solid and liquid phases of five monovarietal commercial wines, even after using different concentration procedures. Nucleic acids presence was then studied in a recent must, during the fermentation process, and during the subsequent steps of winemaking. Genotyping was possible in the resulting experimental wine until decanting, when the particles in suspension were removed. These results suggest that wine authentication through DNA analysis is not possible in commercial wines, in the tested conditions. 相似文献
14.
Chung SH Ryu D Kim EK Bullerman LB 《Journal of agricultural and food chemistry》2005,53(13):5074-5078
Water has been known to be the ideal solvent for moniliformin but is not suitable to extract this toxin from cooked matrices due to instant swelling upon addition of the solvent. In this study, an improved method to extract moniliformin from extruded corn grits using alpha-amylase was developed. In an effort to optimize the method, the efficacy of using a protease was also studied. Treatment with alpha-amylase resulted in a clear solution with decreased suspended solid content as measured by transmittance (%T), which improved from 0 to 96% in 10 min. The detected level of moniliformin from extruded corn grits was increased to 4.02 mug/g when extracted with 1% tetrabutylammonium hydrogen sulfate following alpha-amylase treatment compared to 2.56 microg/g when it was extracted with 90% acetonitrile without enzyme treatment. The average recovery of moniliformin from extruded corn grits was 96% when alpha-amylase was used in the extraction procedure. Overall, the amounts of moniliformin detected in extruded corn grits increased significantly by using enzyme hydrolysis. Chromatographic separation was also benefited by lesser interference and improved peaks. 相似文献
15.
G Takeoka L Dao R Y Wong R Lundin N Mahoney 《Journal of agricultural and food chemistry》2001,49(7):3316-3320
Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission [PIXE] analysis). The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other topical applications. This compound comprised 8.03% (n = 2) of the liquid GSE sample. Higher amounts of benzethonium chloride were found in powder GSE samples. 相似文献
16.
应用水蒸气蒸馏-溶剂萃取法和微波辅助-溶剂萃取法提取了成熟期马铃薯茎叶挥发性成分。用乙醚为萃取溶剂的水蒸气蒸馏法提取时,以0.533%（m/m）得油率获得精油;以正己烷为溶剂的微波辅助萃取法的最适提取条件为：温度60℃,时间9 min,液料比10︰1（V/m）,在此条件下的得油率为0.528%（m/m）。用GC-MS分析检测出水蒸气蒸馏法获得的精油含有81个成分,解析鉴定出占精油相对含量79.386%的43种物质,醇类化合物（24.789%）为主要成分;微波法获得的精油检测出78个成分,解析鉴定出占总精油82.226%的36种成分,酯类化合物（44.482%）为主要成分。2种提取方法获得的精油成分有很大的差别。 相似文献
17.
Takeoka GR Dao LT Wong RY Harden LA 《Journal of agricultural and food chemistry》2005,53(19):7630-7636
Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI/MS), tandem mass spectrometry (ESI/MS/MS), and elemental analysis (by proton-induced X-ray emission analysis). Three major constituents were observed by HPLC and were identified as benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. This mixture of homologues is commonly known as benzalkonium chloride, a widely used synthetic antimicrobial ingredient used in cleaning and disinfection agents. 相似文献
18.
Following smoking 1/2 of a cigar, the most odorous cigar tobacco smoke components extracted from the surface of the tongue by nylon-meshed swabs and then extracted from the swab headspace by solid phase microextraction were ethyl pyrrole, 2,3-dimethyl pyrazine, and 2-ethyl pyridine. Similar classes of compounds were identified from the headspace of an aqueous simulated saliva solution treated with cigar smoke. The most odorous compounds were 2,3,5-trimethyl pyridine, 2,5-dimethyl pyrazine, and 2-ethyl-3,5-dimethyl pyridine. Pyridines and pyrazines, the most prominent classes of odorous compounds identified in this experiment, may be generated during cigar pyrrolysis by cleavage of nicotine or by Maillard reaction. 相似文献
19.
M Zhou K Robards M Glennie-Holmes S Helliwell 《Journal of agricultural and food chemistry》1999,47(10):3941-3953
Recent developments in methods for isolation and measurement of volatiles from cereals are reviewed. The main types of isolation methods, namely, direct extraction, distillation, and headspace, have recently been complemented by solid phase microextraction. Direct solvent extraction provides efficient recovery of compounds with a broad range of polarities and volatilities, whereas headspace techniques provide relatively clean extracts. Supercritical fluid and solid phase microextractions have not yet been fully evaluated for cereals. GC and GC/MS remain the dominant techniques for measurement of the extracted compounds, although new electronic noses show promise. Relating these results to human perception requires careful control to ensure valid comparisons and, in this respect, aroma extract dilution analysis is a useful procedure. 相似文献
20.
Structured lipids (SL) containing caprylic, stearic, and linoleic acids were synthesized by enzymatic transesterification using Lipozyme IM60. Pure trilinolein and free fatty acids were used as substrates. Incorporation of stearic acid was higher than that of caprylic acid in all parameters. Highest incorporations of both acids were achieved at 32 h, mole ratio of 1:4:4 (trilinolein/caprylic/stearic acids), water content of 1% (wt %), temperature of 55 degrees C, and 10% (wt %) enzyme load. The maximal incorporations of caprylic and stearic acids were 23.73 and 62.46 mol %, respectively. Reaction time, water content, and enzyme load had major influences on the reaction, whereas substrate mole ratio and temperature showed less influence. Lipozyme showed good stability over six reuses. Differential scanning calorimetric analysis of SL gave a melting profile with a very low melting peak of 0-3.3 degrees C and a solid fat content of 25.21% at 0 degrees C. The melting profile and solid fat content of SL were compared with those of fats extracted from commercially available solid and liquid margarine products. The data suggest that enzymatically produced SL could be used in liquid margarine products. 相似文献