不同培养条件下的高温型红曲霉培养结果比较

从郎酒厂生产酱香型白酒的高温大曲分离出的14株高温型红曲霉中筛选出极具代表性的4株红曲霉,在不同的培养条件下培养,对其培养结果进行比较分析研充.结果表明,高温型红曲霉在不同的培养条件下,其生理、生化及其在发酵过程中的作用有所不同.     

酸和乙醇对高温型红曲霉培养过程的影响

研究酸和乙醇浓度对高温型白色类红曲霉1#在培养过程中的影响.结果表明,在适宜的浓度下,酸和乙醇在高温型红曲霉培养过程中对其生长情况、产生色素情况及产酯能力都有一定的促进作用;初步确定高温型红曲霉培养过程中比较适宜的酸、醇浓度.     

酱香型郎酒酱味来源之分析推测

通过对酱香型郎酒的生产用曲--高温大曲中几大类微生物的初步分离鉴定及实验室条件下培养,从部分生理特性及感官分析,初步推测高温型红曲霉可能是酱香型郎酒酱味来源的主要微生物种类之一.     

高温型红曲酯化菌株粗酶制剂酯化条件研究

以从郎酒厂酱酒生产用高温大曲中分离筛选出几株产酯能力相对较强的高温型红曲霉为菌种,对其粗酶制剂酯化条件进行初步研究.结果表明,温度相对升高对其酯化力的形成有一定的抑制作用;高温型红曲1#酯化菌株粗酶制剂的酯化力在乙醇浓度为4%vol、己酸含量为4mL时,产生己酸乙酯的能力随酯化时间的延长而增强;在适宜的乙醇浓度和己酸含量范围内,己酸含量对酯化酶粗酶制剂己酸乙酯生成影响比乙醇含量的影响大.     

高产酸性蛋白酶白曲霉培养条件的优化研究

以实验室保藏的白曲霉菌株为目标菌株，从生长条件、产酶活力的关键工艺因素进行研究分析，以提高白曲霉菌株酸性蛋白酶活力为目的，探究高产酸性蛋白酶白曲霉的实验室最佳培养条件。研究结果表明，以麸皮为主要原料，培养基水分添加量为100%，培养基pH值为5，培养温度38℃，培养时间72 h，为该实验菌株的实验室最佳培养条件。     

米曲霉菌种保藏方法的研究

<正> 糖化型米曲霉在食品发酵工业中,是一种常用的微生物菌种。为选择一种简便合适的保藏方法,一九七○年以来,在室温(波动2～40℃)条件下,对米曲霉菌种,采用麸皮法、砂土法和矿油法进行保藏试验,现将结果报道于下。     

Xi-3米曲霉菌株的保藏与复壮

介绍了Xi-3米曲霉菌株的保藏与复壮的具体做法。采用麸皮保藏法可以使Xi-3米曲霉保藏18年之久且菌种优良性状不变；行之有效的复壮措施，提高了保藏菌株的优良性状和生产性能，为种质资源的可持续发展作出了贡献。     

膨化黑毛豆仁保藏期间的品质稳定性

采用微波联合气流膨化技术制备黑毛豆仁脆粒产品,在不同温度和相对湿度条件下保藏6个月,考察其水分含量、水分活度、VC、叶绿素、花色苷、色泽、感官质量及微生物指标的变化情况。结果表明：高温、高湿都可导致产品水分含量和水分活度的增加,VC、叶绿素和花色苷含量降低,a*值增大。膨化黑毛豆仁在温度低于20℃、湿度低于70%的条件下保藏6个月,感官品质良好、符合食品卫生标准。     

发酵法生产衣康酸技术的研究—衣康酸生产菌株的选育（I）

以实验室保藏菌种土曲霉No.201为出发菌株，经餐外线，亚硝基胍（NTG），高温，硫酸二乙酯（DES）诱变处理和多次分离获得一支性能稳定的衣康酸高产突变株土曲霉HAT418，36℃摇瓶发酵72h，衣康酸产量72.1g/L，糖酸转化率60.08%，发酵条件优化后，在含糖120～160g/L的培养基上，产酸81.4～101.1g/L，糖酸转化率63.18%～67.83%，发酵液经高压液相色谱分析，衣康酸占总酸的98.6%。     

以糙米为主要培养基延长米曲霉菌种的保藏期

本研究以糙米为主要培养基并结合真空干燥(-0.1 MPa)和冷冻保藏(-80℃)工艺开发出一种米曲霉长期保藏技术。生产实验表明,利用该方法保藏20年的米曲霉菌种直接制备的大曲中中性蛋白酶、酸性蛋白酶、淀粉酶和葡萄糖淀粉酶的酶活分别达到1871、319、256和2110 U/g干曲。利用该大曲所生产的酱油总氮、氨基酸态氮、总糖、还原糖、无盐固形物含量及原料蛋白质利用率分别达到1.53、0.92、5.39、3.52、19.88 g/100 mL和82.20%。上述指标显著优于利用常规冻干管法保藏20年的米曲霉所制备大曲和酱油的相应指标(p0.05),与利用常规冻干管法保藏5年的米曲霉所制备大曲和酱油的相应指标无显著差异(p0.05)。由聚类分析可知,本方法可比冻干管法延长米曲霉保藏时间15年,在实际生产中可减少菌株复壮次数,避免传代过程中米曲霉突变和污染的几率,进而提高酱油质量稳定性。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

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.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

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.     

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.     

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.     

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.