玫瑰花浸提条件及玫瑰花饮料工艺的研究

将观赏后的玫瑰花瓣用于浸提,研究了浸提温度、浸提时间、柠檬酸含量、料液比对玫瑰花瓣浸提的影响,确定了最佳浸提条件为:温度90℃、时间60min、柠檬酸0.6%、料液比1∶3。根据上述单因素试验结果进行了3因素3水平的正交试验,筛选出玫瑰花饮料最佳配方为:玫瑰花0.6%柠檬酸浸提液15%、白砂糖9%、柠檬酸0.12%。     

对各种涂料抗有机酸性能进行鉴评

11种食品罐头商品涂料试样对8种有机酸的抗性得到鉴评。各种涂料的试样印铁后在以下试液中经121℃处理60分钟:(i)3%氯化钠,1%柠檬酸(ii)1%氯化钠,3%醋酸 (iii)10%蔗糖,2%柠檬酸(iV)1%柠檬酸,0.5%酒石酸(v)1%乳酸     

甲壳素清洁生产过程中柠檬酸钙回收工艺研究

以红虾虾壳为原料,通过碱性蛋白酶脱蛋白、柠檬酸脱钙制备甲壳素,结合超声辅助法,优化副产物柠檬酸钙回收工艺条件,并对甲壳素成品和柠檬酸钙进行主要质量指标检测。在单因素实验的基础上,通过Box-Behnken实验设计对柠檬酸浓度、液料比和超声时间进行优化,得出了柠檬酸钙回收的最佳工艺条件为:柠檬酸浓度10%,液料比12:1 mL/g,超声时间50 min,柠檬酸钙得率为93.49%±0.07%,甲壳素的得率达到18.93%±0.06%,甲壳素成品质量达到食品级标准,柠檬酸钙成品质量符合我国柠檬酸钙食品添加剂要求。本研究为甲壳素清洁生产过程中柠檬酸钙的回收利用提供科学的理论依据。     

4-己基间苯二酚对切分果蔬及莲藕汁护色效果的研究

用4-HR(4-己基间苯二酚)对苹果、马铃薯、香蕉切片和莲藕汁的护色进行了研究。实验结果表明4-HR组合防褐试剂对上述四种材料均表现良好的护色效果,其中对苹果切片的最佳组合是A2B2C1,即0.02%4-HR、0.03%抗坏血酸、0.5%柠檬酸;香蕉最佳组合是A2B2C2,即0.02%4-HR、0.03%抗坏血酸、0.75%柠檬酸;马铃薯切片和莲藕汁的最佳组合都是A1B1C2,即0.01%4-HR、0.02%抗坏血酸、0.75%柠檬酸。     

牡蛎壳制备柠檬酸钙的工艺研究

以柠檬酸钙产率为指标研究牡蛎壳制备柠檬酸钙的工艺,通过单因素实验探讨盐酸用量、碳酸钠用量对碳酸钙得率的影响及柠檬酸用量、水用量和结晶时间等因素对柠檬酸钙产率的影响。结果表明:1 g牡蛎壳粉在20 m L1 mol/L盐酸、1.5 g碳酸钠的条件下制备的碳酸钙得率最佳,达到92.3%;在此条件下,1.5 g柠檬酸与碳酸钙在15 m L水中反应,30℃下结晶4 h,柠檬酸钙的产率为91.24%。说明牡蛎壳用此工艺制备柠檬酸钙产率高,可实际应用。     

鲜切西洋芹联合保鲜技术的研究

对鲜切西洋芹过氧化氢、柠檬酸与氯化钙的联合保鲜研究表明 ,0 .1 5 %过氧化氢 0 .1 %柠檬酸 0 .4 %氯化钙可有效杀灭鲜切菜表面的微生物 ,抑制酶的活性 ,降低呼吸作用和蒸腾作用 ,固形物含量、pH值、Vc等理化指标及感官品质均优于对照     

刺梨复合果糕的研制

以刺梨和红枣为主要原料,通过单因素试验研究混合原料（刺梨汁和红枣汁）、复配胶凝剂、白砂糖、柠檬酸的添加量对刺梨复合果糕的影响。结果表明：选择混合原料配比为刺梨汁与红枣汁体积比1∶2;选择琼脂、卡拉胶、果胶3种胶凝剂的复配质量比1∶1∶2,通过正交试验得出：混合原料、白砂糖、复配胶凝剂和柠檬酸4个因素对刺梨复合果糕的影响程度为混合原料＞白砂糖＞复配胶凝剂＞柠檬酸;刺梨复合果糕的最佳配方：35%混合原料、15%白砂糖、1.5%复配胶凝剂和0.3%柠檬酸,感官评分最高为89.95。     

分光光度法测定柠檬酸发酵成品中硫酸盐与氯离子的研究

研究采用可见光-分光光度比色法代替目视比色法检测柠檬酸成品中硫酸盐与氯离子的含量,结果表明,检测波长为400nm、柠檬酸测定浓度为4%(1g定容至25mL)时,柠檬酸成品中硫酸根与氯离子含量与透光率具有很好的线性关系,线性方差可达到99.8%.     

蜂蜜果冻的研制

介绍了蜂蜜取代白糖制作果冻的意义;对以蜂蜜、柠檬酸和复合胶粉为原料制作果冻的工艺配方进行了研究。结果表明,当蜂蜜30%、柠檬酸0.25%、复合胶粉1%～1.2%时生产出的果冻具有天然蜂蜜的风味,口感良好。     

芦荟番石榴蜂蜜果冻的研制

试验以芦荟、番石榴、蜂蜜为原料,添加适量的柠檬酸、胶凝剂,研制出口感优良,风味独特,质量稳定的复合果冻。通过正交试验和感官评定确定产品的最佳配方为:芦荟与番石榴混合果汁30%,甜味剂5.3%,柠檬酸0.03%,混合胶凝剂(果冻粉:琼脂粉:海藻酸钠=1:2:1)0.6%。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.