首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
高压电场制备W/O/W复乳微囊的试验研究   总被引:1,自引:0,他引:1  
张瑶  李保国 《食品科学》2006,27(2):163-166
为探索水溶性物质微囊化新方法,利用高压电场微胶囊成型装置制备W/O/W型微囊,内水相为蒸馏水,油相为液体石蜡,外水相为海藻酸钠溶液。研究了电压、液面距、推进速度、初乳/外相水溶液、海藻酸钠浓度对微囊粒径的影响。结果表明:在成囊范围内,电压、液面距和外水相海藻酸钠溶液浓度对微囊的粒径有较为显著的影响。在电压3.15-4kV,液面距2.5~10cm,海藻酸钠浓度0.6%~1.2%条件下,可以制得微囊粒径范围为50~1000μm之间,大小均匀的复乳微囊。  相似文献   

2.
目的:提高熊果酸的应用范围和生物利用率。方法:以熊果酸为乳化剂,果胶为外水相,采用两步法制备W/O/W型Pickering乳液。通过单因素试验优化W/O乳液制备条件,研究果胶质量浓度对W/O/W型Pickering乳液理化性质、微观结构、流变学特性及长期稳定性的影响。结果:W/O乳液的最佳制备工艺为熊果酸质量浓度4 g/100 mL、水油质量比2∶3、均质转速9 000 r/min、均质时间5 min;以果胶为外水相制备的双层乳液粒径均在30~40μm,果胶质量浓度的增加使乳液的zeta电位绝对值、流变性能以及4℃贮藏稳定性有着显著性的提高。结论:果胶质量浓度为0.3,0.4,0.5 g/100 mL时能够制备稳定的Pickering双层乳液。  相似文献   

3.
魏慧贤  钟芳  麻建国 《食品与机械》2007,23(6):35-38,47
目的:研究用两步乳化法制备W/O/W型复合乳状液时,第一相体积比(内水相与油相的体积比)、第二相体积比(初乳与外水相的体积比)对W/O/W型复合乳状液性质的影响;方法:采用两步乳化法制备W/O/W型复合乳状液,固定制备工艺条件,改变第一相体积比和第二相体积比的数值制备初乳和复乳,用离心分层稳定性评价复乳的稳定性,初乳的离心稳定性、黏度和复乳的粒度分布被测定;结果:随着第一相体积分数增大,初乳黏度增大,初乳和复乳的离心稳定性都提高,但是内水相的体积分数达到65%时,初乳表现出凝胶的外观,所制备的复乳的稳定性反而降低,当内水相的体积分数增加到70%的时候,初乳转相形成O/W型乳状液,不能进一步制备复乳;随着第二相体积分数的增大,复乳黏度线性增大,复乳滴的体积平均粒径减小,复乳的离心稳定性提高。初乳中内水相与油相的适宜的体积比及复乳中初乳和外水相的适宜体积比皆为1:1左右。  相似文献   

4.
利用超临界CO2抗溶剂法从乙基纤维素和丙酮溶液中制得了乙基纤维素微囊,考察了温度、压力、溶液浓度和搅拌速度等工艺参数对物性的影响,试验结果表明:超临界CO2抗溶剂法可用于食品材料的微囊制粒,所得乙基纤维素微囊的粒径在2.66~9.49μm之间;随着温度和溶液浓度的增加,颗粒粒径及其粒径分布增加;随着压力和搅拌速度的增加,颗粒粒径及其粒径分布减小。  相似文献   

5.
提高W/O/W多重乳状液的稳定性研究   总被引:8,自引:0,他引:8  
研究了W/O/W多重乳状液稳定性的影响因素。实验表明,W/O/W多重乳状液制备的较佳工艺操作条件为乳化温度40℃,pH值2.5,W/O/W搅拌时间25min,第一相体积比0.48,第二相体积比0.66。  相似文献   

6.
刘欣  郭星尧  韩亚  刘淑萍 《现代食品科技》2009,25(9):1043-1045,1015
研究了采用海藻酸钠为囊材,CaCl2溶液为固化液,锐孔法制备铁叶绿酸钠微囊的工艺条件.在实验中,探讨了固化液的浓度、囊材浓度、针头孔径、下滴高度、搅拌速度、乳化剂浓度等实验参数对微囊形态及包封率的影响.结果表明:以海藻酸钠为囊材锐孔法制备铁叶绿酸钠微囊的最佳工艺条件是海藻酸钠的浓度为1%,CaCl2溶液的浓度为2%,海藻酸钠溶液与铁叶绿酸钠溶液的浓度比为1:1,针头孔径0.45 mm,转速800 r/min,下滴高度10 cm.铁叶绿酸钠微囊产品为墨绿色小颗粒,外形颗粒圆整,大小均匀,赋有青草味.  相似文献   

7.
以葡萄皮花色苷(ACNs)提取物为内水相(W1),玉米油为油相,乳清蛋白(WPI)溶液为外水相(W2)制备水包油包水(W/O/W)型复乳。复乳的包埋率高达(93.19±2.78)%,平均粒径为(287.90±3.12)nm。经口腔消化后,乳液未发现有明显变化;模拟胃部消化后,乳液液滴相互融合形成具有双层结构的较大微粒,其平均粒径(d>600 nm)显著增加(P<0.05)。经模拟肠道消化后,微粒成为空油滴,其平均粒径为(387.53±15.96)nm,此时抗氧化活性最高。研究结果表明,W/O/W型复乳在口腔和胃部能有效保护ACNs,实现靶向性肠道输送。负载ACNs的复乳系统在食品工业中有很大的应用潜力。  相似文献   

8.
壳聚糖-海藻酸钠缓释制备红景天苷微囊   总被引:11,自引:1,他引:10  
用壳聚糖 海藻酸钠微囊技术制备了一系列红景天苷微囊。试验结果表明 :海藻酸钠的浓度、壳聚糖的浓度及壳聚糖溶液的pH值对海藻酸钠 壳聚糖微囊的包埋率、载药量及缓释性能有影响 ,海藻酸钠和壳聚糖微囊能作为红景天苷活性成分的载体。  相似文献   

9.
考察了海藻酸钠质量浓度、气速及进料速度对嗜酸乳杆菌微胶囊粒径及粒径分布的影响。得到微胶囊的优化制备条件如下:海藻酸钠质量分数为1.5%、气速为450 L/h、进料速度为1 mL/min。采用优化制备工艺进行微胶囊制备,验证优化结果。结果表明,制备的微胶囊粒径及粒径分布相近,微囊粒径大小为30μm左右,说明优化试验得到的制备工艺真实可靠。优化了微囊制备工艺后,考察了菌加入量对微囊粒径/形貌和微囊对菌包埋率的影响,最终选取含菌量为109CFU/mL进行嗜酸乳杆菌微胶囊的制备。微胶囊粒径维持在30μm左右,粒径分布比较均一,对嗜酸乳杆菌的包埋率达到79.77%,可用于后续胃肠道微环境调节研究。  相似文献   

10.
通过添加天然大分子提高W/O/W型多重乳状液的稳定性。外水相中添加的乳清分离蛋白(WPI)与羧甲基纤维素(CMC)两种物质形成的混合物,可作为亲水性稳定剂来提高乳状液的稳定性。采用两步法制备W/O/W型多重乳状液,研究不同的外水相pH值、WPI与CMC的比例和添加量对W/O/W型多重乳状液性质的影响;以粒径、zeta-电位、黏度、稳定性等指标确定W/O/W型多重乳状液的最优制备条件。研究结果表明:当pH=6时,WPI与CMC的比例10∶1,添加量4.4%,WPI与CMC相互作用形成的混合物吸附在油水界面,形成的界面膜的厚度及韧性较好,W/O/W型多重乳状液的粒径较小,稳定性较高(79%)。  相似文献   

11.
Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.  相似文献   

12.
An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.  相似文献   

13.
The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.  相似文献   

14.
The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.  相似文献   

15.
16.
A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.  相似文献   

17.
BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H2O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.  相似文献   

18.
Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH3CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH2PO4-20.6 mM Na2B4O7 buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.  相似文献   

19.
20.
This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号