牛至精油-β-环糊精微胶囊制备工艺研究

以β-环糊精为壁材,采用分子包埋法制备牛至精油-β-环糊精微胶囊。在单因素试验基础上,采用正交试验优化了牛至精油-β-环糊精微胶囊的制备工艺。结果表明,牛至精油-β-环糊精微胶囊的最佳制备工艺为搅拌时间3 h、牛至精油与无水乙醇的体积比1∶5、环糊精的质量6 g、搅拌温度50℃,在此条件下,制备的牛至精油-β-环糊精微胶囊的包埋率为55.14%。     

牛至精油微胶囊的制备及其在抗菌食品包装纸中的应用

以羟丙基-β-环糊精（HP-β-CD）为壁材,牛至精油为芯材,通过饱和水溶液法制备牛至精油-HP-β-CD微胶囊,与涂料复合涂布制备抗菌食品包装纸。结果表明,微胶囊的最佳制备工艺为包合时间3 h、包合温度50 ℃、芯壁比1∶8。在此工艺条件下制备的牛至精油-HP-β-CD微胶囊的芯材包合率为83.69%,具有良好的缓释效果,微胶囊及其制备的抗菌食品包装纸对金黄色葡萄球菌和大肠杆菌具有良好的抑菌性能。     

不同壁材丁香精油微胶囊保鲜剂性能研究

采用饱和水溶液法,以β-环糊精和壳聚糖为壁材,丁香精油为芯材与壁芯比为4∶1制备3种丁香精油微胶囊保鲜剂,并对三种组合壁材微胶囊保鲜剂的表面形态、光照稳定性、包埋率、缓释效果以及抑菌效果进行测定,结果表明β-环糊精丁香精油微胶囊的包埋率最高,为67%;β-环糊精-壳聚糖丁香精油微胶囊1的光照稳定性最好,丁香精油损失率仅为32.67%;β-环糊精-壳聚糖丁香精油微胶囊1的缓释效果最好;β-环糊精-壳聚糖丁香精油微胶囊1的抑菌圈直径最大(38.5±0.40 mm)。综合考量得β-环糊精-壳聚糖1为壁材制得的丁香精油微胶囊性能最好。     

壳聚糖涂膜与牛至精油复配对鲜切菠萝的 保鲜作用

目的研究壳聚糖涂膜及与牛至精油复配对鲜切菠萝的保鲜的影响。方法在低温环境中,按照0.1%、0.3%和0.5%不同浓度的牛至精油与壳聚糖复配,并分别以水、壳聚糖涂膜处理为对照,分析不同处理方式对鲜切菠萝硬度、Vc含量、过氧化物酶(POD)、多酚氧化酶(PPO)、过氧化氢酶(CAT)和脂氧合酶(LOX)活性的影响。结果壳聚糖涂膜与0.5%的牛至精油复配后可减缓组织软化;与0.1%牛至精油复配可以维持Vc含量的缓慢降低。在不同处理组中,当含有0.3%和0.5%牛至精油时,鲜切菠萝的POD和CAT活性则呈下降趋势,而其他处理组则显著升高;当含有壳聚糖处理组时,其PPO和LOX活性则低于对照组。结论壳聚糖与牛至精油复配涂膜会在减缓鲜切菠萝营养损失的情况下延长其货架期。     

壳聚糖-姜精油涂膜对草莓贮藏品质的影响

采用浓度为1%的壳聚糖与不同浓度(0.05%、0.10%、0.20%)的姜精油配制成保鲜液,对草莓进行涂膜处理,研究壳聚糖-姜精油对草莓贮藏品质的影响。结果表明,不同浓度的姜精油与壳聚糖保鲜液对草莓的保鲜效果表现不一,较低浓度的壳聚糖-姜精油保鲜液能够降低草莓的腐烂率、失重率、细胞膜的透性和丙二醛含量,减少可滴定酸、VC和可溶性糖含量的损失,有效地保持草莓的感观品质,能够更好地延缓草莓贮藏品质的下降。其中,壳聚糖-0.10%姜精油保鲜液处理草莓的贮藏品质最佳,而壳聚糖-0.20%姜精油保鲜液处理的草莓贮藏品质较差。     

微胶囊双水相体系萃取地椒精油

采用β-环糊精-硫酸钠微胶囊双水相体系萃取地椒精油,考察β-环糊精、硫酸钠、萃取温度和萃取时间对精油收率的影响。得出适宜萃取条件为:45%的β-环糊精、20%的硫酸钠,40℃萃取20 min,精油平均收率为96.67%。抑菌实验结果表明:地椒精油具有较好的抗菌效果,其抑菌效果优于0.1%山梨酸钾。     

成品粮丁香精油微囊化防霉保鲜剂的研制

以丁香精油为芯材,β-环糊精和壳聚糖为壁材,采用包络结合法制备微胶囊,以正交优化的的方式确定制备微囊化的最佳环糊精浓度、壳聚糖浓度、乳化剂的浓度以及壁芯比,并对最佳配方的保鲜剂进行SEM表征、缓释效果测定以及防霉性的测定,结果表明:微囊化丁香精油的制备配方及工艺条件为:环糊精6.0%,壳聚糖1.0%,均相乳化剂吐温-80 0.2%,壁芯比4∶1;微囊化防霉保鲜剂的SEM图片显示粉末状微胶囊呈不定性状,保鲜剂呈缓慢释放的状态,并且具有防霉性。     

桉叶精油β-环糊精微胶囊制备工艺的研究

桉叶精油具有广泛的生物活性,但其易挥发性使其应用受到了限制。为扩大桉叶精油的应用范围,以β-环糊精为壁材,采用饱和水溶液法制备桉叶精油微胶囊。综合考察了包埋温度、包埋时间、壁芯比、乙醇与精油比、水与β-环糊精比等单因素对微胶囊包埋效果的影响,在此基础上,采用正交实验优化了桉叶精油β-环糊精微胶囊的制备工艺。结果表明:壁芯比、包埋温度和包埋时间对包埋效果影响显著,而乙醇与精油比、水与β-环糊精比对包埋效果影响较小。确定了最佳制备工艺为:包埋温度40℃,包埋时间2 h,壁芯比10∶1,乙醇与精油比25∶1,水与β-环糊精比10∶1,此条件下制备的桉叶精油β-环糊精微胶囊包埋率为70.33%,包埋得率为86.27%。     

羟丙基-β-环糊精包合薰衣草精油工艺及性质分析

为了提高薰衣草精油的物理化学稳定性,采用羟丙基-β-环糊精对其进行包埋。并通过响应面法优化薰衣草精油包合物的制备工艺,以期找到一种最佳的包合工艺条件。同时,利用红外光谱和拉曼光谱分析方法,实现对薰衣草精油包合物的结构及包合情况分析,进而验证薰衣草精油被羟丙基-β-环糊精较好的包埋。实验所得的最佳包合工艺为:羟丙基-β-环糊精与薰衣草精油比例6.27:1(g:mL)、包合温度33.1℃、包合时间3.36 h,包合率可达80%。通过光谱分析可知,羟丙基-β-环糊精和包合物谱图极其相似,这说明薰衣草精油中许多基团被包埋进入环糊精空腔。结果表明,羟丙基-β-环糊精包合精油效果较好,该优选工艺稳定可行,能够为薰衣草精油的应用提供一定参考。     

抗菌功能纸盒对草莓保鲜效果的影响

目的:制得一种对草莓具有保鲜效果的抗菌功能纸盒。方法:通过对丹皮进行粉碎、加水、超声、过滤、高速离心制得丹皮提取液,利用丹皮提取液与海藻酸钠、β-环糊精复配然后结合聚乙烯醇制成抗菌涂布液涂布于白卡纸上,制成纸盒,并对丹皮提取液的成分进行紫外分析,采用抑菌圈实验测试丹皮提取液对供试微生物的抑制作用,探究这种抗菌纸盒对草莓的保鲜效果。结果:丹皮提取液对供试微生物青霉菌具有抑菌作用,涂布液中丹皮提取液加海藻酸钠与聚乙烯醇结合后的抗菌纸盒抑菌效果最强。涂布液中丹皮提取液加β-环糊精与聚乙烯醇结合的抗菌纸抑菌效果次之,但其对维持草莓感官品质、抑制草莓的腐烂等具有明显的效果,显著优于提取液加聚乙烯醇的抗菌纸及原纸。结论:涂布液中丹皮提取液和海藻酸钠复配与聚乙烯醇结合的抗菌纸盒对草莓具有较好的保鲜效果。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

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.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

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.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.