用精炼糖糖蜜制备高色率和高红色素指数焦糖色素的工艺研究

焦糖色素的色率和红色素指数是衡量焦糖色素品质的2个重要指标,但这2个指标是相互制约的。本文以精炼糖糖蜜为原料,利用氨法制备焦糖色素。通过单因素实验研究,确定影响焦糖色素色率和红色素指数的主要因素为反应温度、反应时间和催化剂的量,然后以此设计正交实验,确定制备高色率焦糖色素的工艺为反应温度120～125℃,反应时间1.5 h,铵盐添加量为10%（以NH4＋的质量与糖蜜干固物质量计算）;制备高红色素指数焦糖色素的工艺为反应温度110～115℃,反应时间0.5 h,铵盐添加量3%（以NH4＋的质量与糖蜜干固物质量计算）。     

耐酸型焦糖色素制备工艺的研究

对以葡萄糖为原料,复合氨基化合物为催化剂制备耐酸型焦糖色素的工艺进行了研究,在单因素实验基础上,通过正交实验得出较好的工艺条件为糖液浓度60%、保温温度145℃、保温时间3h、催化剂用量5%,得到色率达163626,带负电荷的耐酸焦糖色素产品。     

低4-甲基眯唑含量的焦糖色素制备工艺的研究

本文以精炼糖糖蜜为原料,采用氨法成功制备出低4-甲基咪唑含量的焦糖色素。通过单因素试验研究,确定了影响焦糖色素中4-甲基咪唑含量的主要因素及其合理的正交实验水平范围,再以正交实验确定制备低4-甲基咪唑含量焦糖色素的工艺为：反应温度115℃,反应时间90min,在反应过程中逐滴加入铵盐,铵盐添加量为6％。     

响应面分析法优化亚硫酸铵制备焦糖色素工艺研究

主要研究了用响应面分析法(RSA)对亚硫酸铵制备焦糖色素中保温温度、保温时间、糖液浓度和催化剂用量工艺参数进行优化,同时对试验结果进行方差分析,结果表明:最佳工艺参数为保温温度142℃、保温时间58min、糖液浓度40%和催化剂用量4%,指标与全体自变量二次项之间的线性关系明显(Pr0.05,达到显著)。     

低4-甲基咪唑焦糖色素制备工艺优化

为研究减少焦糖色素中4-甲基咪唑(4-Methylimidazole,4-MeI)生成的工艺,以葡萄糖为原料,碳酸铵为催化剂,利用高压反应制备4-甲基咪唑含量低、色率及红色素指数高的焦糖色素。采用正交试验设计考察了反应温度、反应时间、催化剂添加量(以NH₄+计)、葡萄糖液质量浓度四个因素对焦糖色素的色率、红色指数、4-甲基咪唑含量的影响。结果表明,利用综合平衡法确定生产参数为135 ℃、80 min、3% NH₄+及500 g/L 葡萄糖浓度,制备得到的氨法焦糖色素色率6.73×104 EBC,红色素指数5.21,4-甲基咪唑的含量198.34 μg/mL。通过对焦糖色素的生产工艺进行优化,得到了4-MeI明显降低的焦糖色素,为其生产提供了理论依据。     

甘蔗糖蜜生产焦糖色素的研究

本文研究了甘蔗糖蜜生产焦糖色素的可行性，提出了去除糖蜜中灰分和胶体的预处理方案和优化的焦糖生产工艺。糖蜜以硫酸调节pH至2．3，同时添加适量的澄清剂，经离心获得的糖蜜清液适于制造澄清度极好的焦糖色素。正交试验结果表明，温度、反应时间和(NH4)2SO4添加量对焦糖色率和红色素指数都有显著的影响。在115℃，添加糖蜜量的条件下反应120min，可生产出澄清度高，色率为≥30000EBC，红色素指数≥5．5，耐酸性极好的优质焦糖色素。     

正交实验法优化酱油用焦糖色素的制备工艺

以葡萄糖和碳酸铵为原料,优化酱油用焦糖色素的制备工艺。采用正交实验法,研究保温温度、保温时间、助剂质量分数及糖液质量浓度对焦糖色素的色率和红色指数的影响。结果表明:在保温温度140℃,保温时间70min,助剂质量分数7%,葡萄糖质量浓度为50%(w/v)的条件下可获得具有较好色率的产品,色率可达76579BEC。在保温温度130℃,保温时间60min,助剂质量分数5%,葡萄糖质量浓度为40%(w/v)的条件下可获得具有较好红色指数的产品,红色指数可达5.569。在保温温度135℃,保温时间60min,助剂质量分数6%,葡萄糖质量浓度为50%(w/v)的条件下可获得同时具有高色率和高红色指数的产品,色率可达43632BEC,同时红色指数达到5.34,优于市售焦糖色素。     

甘蔗糖蜜生产焦糖色素的研究

本文研究了甘蔗糖蜜生产焦糖色素的可行性,提出了去除糖蜜中灰分和胶体的预处理方案和优化的焦糖生产工艺。糖蜜以硫酸调节pH至2.3,同时添加适量的澄清剂,经离心获得的糖蜜清液适于制造澄清度极好的焦糖色素。正交试验结果表明,温度、反应时间和(NH4)2SO3添加量对焦糖色率和红色素指数都有显著的影响。在115℃,添加糖蜜量 的条件下反应120 min,可生产出澄清度高,色率为≥30000EBC,红色素指数≥5.5,耐酸性极好的优质焦糖色素。     

化学法制备赤藓糖的研究

赤藓糖是一种带有还原性醛基的四碳糖,在常规条件下结构不稳定,可通过加氢反应进一步制备赤藓糖醇。化学法制备赤藓糖的成功打破了赤藓糖醇行业目前仅由发酵法来实现的局限,对行业整体生产成本的降低具有重要的意义。本文所提的工艺是用葡萄糖酸钠配成溶液,在搅拌及一定的温度条件下,以六水氯化钴为催化剂,通过双氧水氧化制备赤藓糖。先通过单因素试验确定了葡萄糖酸钠的浓度、六水氯化钴和双氧水的用量、反应温度、双氧水加入时间等条件的变化曲线。通过正交实验筛选出葡萄糖酸钠氧化制备赤藓糖的最佳工艺条件,即六水氯化钴添加量为葡萄糖酸钠质量的1.4%、双氧水添加量和葡萄糖酸钠质量相同、葡萄糖酸钠溶液的浓度10%、氧化温度控制在40℃、在此最佳工艺条件下葡萄糖酸钠氧化为赤藓糖的转化纯度为59.9%。     

高品质焦糖色素(Ⅳ)的制备工艺优化

为优化制备高色率焦糖色素的工艺,以葡萄糖为反应物,亚硫酸铵为助剂,制备焦糖色素(Ⅳ)。通过控制葡萄糖浓度、铵含量、反应温度、反应时间等因素,以色素色率为主要检测指标,红色指数和黄色指数为辅助检测指标对结果进行优化。结果表明,高品质焦糖色素(Ⅳ)的最佳工艺条件为:葡萄糖浓度1000g/L,亚硫酸铵添加质量分数(以NH4+的量计)为6%,反应温度为150℃,反应时间为60min。制成焦糖色素的色率达7.47×104EBC。     

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.