姬松茸深层发酵培养基的优化

通过姬松茸碳氮源筛选的单因素实验 ,确定玉米粉、蔗糖为碳源 ,豆粕粉、麸皮汁为氮源 ;在此基础上 ,进行了碳氮源质量浓度及比例实验、摇瓶发酵正交实验 ,优化培养基配方 ,确定姬松茸摇瓶发酵培养基的最佳配方为 :玉米粉 1 .5g/dL ,蔗糖 0 .5 g/dL ,麸皮汁 0 .5 g/dL ,豆饼粉 2 .0 g/dL .     

羊肚菌液体深层发酵条件

以羊肚菌为材料，研究了发酵过程中碳源、氮源、无机盐、培养条件对菌丝体生物量、胞外多糖的影响，以及发酵过程中菌丝体生物量、胞外多糖、总糖及还原糖质量浓度、培养基PH值的动态变化，并在此基础上确定了羊肚菌液体深层发酵的最佳条件。结果表明：羊肚菌液体深层发酵的最优培养基配比为：玉米粉4．0g／dL、葡萄糖1．0g／dL、黄豆粉2．0g／dL、酵母粉0．3g／dL、KH2PO4 0．2g／dL、MgSO4 0．1g／dL、CaSO4 0．1g／dL；最优培养条件为：24℃，起始pH5．8，250mL的摇瓶装液量为100mL，接种量10mL，摇瓶转速140r／min，发酵时间为108h。     

香菇深层发酵培养条件的优化

通过单因子试验,研究了装液量、培养基pH值、培养温度、培养时间及转速对香菇菌丝摇瓶发酵的影响,并通过正交试验确定了香菇深层发酵的优化条件,即采用250mL摇瓶发酵,培养基初始pH值为6,装液量100mL,培养温度26℃,转速125r／min,发酵14d。采用优化的发酵条件进行香菇菌丝摇瓶发酵,干菌丝体得率高达0．729g/100mL。     

金针菇深层发酵产呈味核苷酸培养条件的研究

通过单因子实验,研究了温度、装液量、pH及转速对金针菇摇瓶发酵产呈味核苷酸的影响,确定了金针菇深层培养的最佳条件为：250mL摇瓶发酵装液量为100mL,最适培养温度为26℃,适宜培养pH6～7,摇床转速120r/min。利用此培养条件进行了最适培养期试验,结果表明26℃培养7～8d,金针菇菌丝生物量达26.52g/L,呈味核苷酸产量达0.26g/L。     

鸡腿蘑菌株筛选及深层发酵培养基的优化

对4个鸡腿蘑菌株进行了发酵筛选,选出生物量较高的菌株农林鸡腿蘑(NL),并通过单因素试验,确定玉米粉、蔗糖为碳源,麸皮为氮源;在此基础上,以筛选的碳源、氮源和无机盐KH2PO4和MgSO4·7H2O为考察因素,以生物量为主要指标利用正交试验优化培养基配方比例,确定鸡腿蘑摇瓶发酵培养基最佳配方为:玉米粉 4 g/dL,蔗糖 2 g/dL,麸皮 4 g/dL,KH2 PO4 0.1g/dL,MgSO4·7H2O 0.1 g/dL.     

平菇液体菌种摇瓶和发酵罐生长动力学模型的比较

作者选用玉米粉豆粕粉蔗糖液体培养基,分别采用摇瓶和40 L全自动机械搅拌通风发酵罐培养平菇天达300液体菌种,两种培养方式的茵丝体生长动力学模型均符合Logistic方程.摇瓶培养周期为8 d,最大比生长速率是0.050 h-2,茵丝体质量浓度是1.5001 g/dL,发酵罐培养周期是84 h,最大比生长速率是0.110 h-1,菌丝体质量浓度是1.4750 g/dL.应用发酵罐培养平菇天达300液体菌种更为高效.然而,摇瓶培养的液体菌种菌丝球直径小,单位体积培养液中菌丝球数量是发酵罐的1.4倍,可能与发酵罐培养过程中培养液的粘度下降速度快于摇瓶有关.     

深层液体发酵生产纳他霉素的工艺研究

在前期摇瓶发酵培养研究的基础上,采用自行设计的50L小型直叶搅拌通风发酵罐,利用在线监控手段直接监测分析褐黄孢链霉菌ZC128深层液体通风发酵生产纳他霉素的工艺条件,得出最佳发酵工艺为葡萄糖20g/L,淀粉50g/L,酵母粉5g/L,黄豆饼粉25g/L,温度28℃,pH值7.0~7.2,通气量1.8m3/h,转速700r/min,发酵12h左右时加入0.3g/L的豆油。在上述条件下进行流加糖分批发酵培养96h,培养液中纳他霉素的产量可达到4287μg/mL,比该菌种的摇瓶分批发酵产量(3252μg/mL)提高了31.8%。     

杏鲍菇液态发酵培养的初步研究

杏鲍菇是一种珍贵的药食皆宜的真菌.为在较短时间内大量获得杏鲍菇菌体,该试验探讨了液态发酵方法制备杏鲍菇.试验以杏鲍菇菌丝体干重为指标,通过单因素试验和正交试验,对杏鲍菇液态发酵培养基和液态发酵条件进行了优化.试验结果表明,杏鲍菇液态发酵的最佳碳源为葡萄糖,最佳氮源为蛋白胨,当培养基配方为葡萄糖30g/L、蛋白胨5g/L、KH2PO40.8g/L、MgSO41.2g/L、VB110mg/L时杏鲍菇菌丝体生物量较高.在摇瓶培养条件中研究了种龄、装液量、初始pH值、接种量、温度、转速、培养时间等对液态发酵杏鲍菇菌体生物量的影响.得出最佳培养条件:种子培养6d,装液量20％ (v/v),接种量为10％ (v/v),培养基的初始pH值为自然,培养温度为25℃,摇瓶转速为140r/min,发酵8d,杏鲍菇菌丝产量可达8.23g/L.     

菌株SFGi-1产赤霉素发酵条件的研究

通过摇瓶培养对菌株SFGi-1产赤霉素的培养基和培养条件进行了优化,确定最佳发酵培养基为液化淀粉100g/L,花生饼粉15g/L,豆粕粉3g/L,硫酸镁0.75g/L,磷酸二氢钾1.0g/L:培养条件为培养温度30℃,接种量5%,250mL摇瓶装液量为35mL,起始DH值为5.5,发酵时间204h.在此条件下,菌株SFGi-1赤霉素发酵最高效价可达到1424mg/L.     

混合菌株固态发酵玉米皮生产饲料蛋白

以玉米皮为基本碳源,通过单因素试验和正交试验,对康宁木霉和假丝酵母混合固态发酵生产饲料蛋白进行了研究.以提高木聚糖酶活和真蛋白含量为主要目的,优化得到最佳培养条件为:麸皮25 g/dL,玉米皮75 g/dL,初始固液比为1:1.5,酵母接种体积分数为10%,30℃培养7d.在此条件下,最终得到的产品的木聚糖酶活力为1 300 IU/g左右,真蛋白含量达到20%以上.     

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.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.