桑椹果醋发酵工艺的优化

通过对接种量、装瓶量、初始pH、初始酒度、发酵温度的醋酸发酵单因素试验,以及对初始酒度、接种量、初始pH和发酵温度的醋酸发酵四因素三水平,即L9（34）正交试验,发酵时间8d,以总酸产量为优化指标,试验得出：影响桑椹果醋发酵的主次因素为初始酒度〉发酵温度〉初始pH〉接种量;醋酸发酵的最佳工艺参数为初始酒度7%,接种量9%,初始pH 4.5,发酵温度30℃,在此条件下,桑椹果醋总酸产量为63.02g/L。根据对桑椹果醋各项指标的评定和测定,桑椹果醋的感官指标、理化指标、微生物指标均符合中华人民共和国国家标准。     

杏果醋液态深层发酵工艺优化

采用酒精发酵和液态深层醋酸发酵两步法,研究了杏果醋的发酵工艺。通过L9(34)正交试验优化得到最佳酒精发酵工艺条件为:初始糖度16°Bx、酵母接种量3%、酒精发酵温度30℃,发酵液的酒精度达8.6%。采用4因素二次通用旋转组合试验设计,通过响应面法对醋酸发酵条件进行了研究。结果表明,起始酒精度、醋酸菌接种量、摇床转速及发酵温度4个因素对杏果醋总酸含量有极显著影响(P<0.01)。在初始酒精度为6.7%、醋酸菌接种量为13%、发酵温度为34℃、摇床转速为153 r/min的最佳工艺条件下,杏果醋酸发酵液的总酸(以醋酸计)为7.11 g/100 mL,挥发酸(以醋酸计)为6.23 g/100 mL。     

发酵秸杆生产耐高温纤维素酶工艺条件的研究

对绿色木霉110发酵秸秆生产纤维素酶上艺条件进行了研究，通过正交试验和扩大试验，确定了绿色木霉固体发酵生产纤维素酶的最佳工艺条件为干料：水=1：1，原料配比（稻草：麸皮）为6：4，容器装料量7％，接种量3％，培养温度38℃，发酵周期72h，试验因素的影响顺序为水分〉原料配比〉装料量〉接种量。在最佳工艺条件下，产酶酶活超过25300U/g。     

液体发酵柿子醋的工艺研究

通过正交实验确定了柿子醋生产过程中酒精发酵的最佳工艺参数:发酵温度30℃,发酵周期5d,接种量10%;正交实验确定了醋酸发酵的主要工艺参数:初始酒精度5%,发酵温度34℃,醋酸菌接种量10%。醋酸发酵液经过滤直接作为调味品,也可以调配成不同风味的果醋饮料。     

枸杞枣醋的研制

利用枣制品下脚料枣液和枸杞通过酶解、酵母发酵、醋酸发酵等工艺研制了枸杞枣保健醋。通过正交实验确定了酵母发酵最佳工艺为总糖含量10％，酵母接种量0．02％，发酵温度30℃；醋酸发酵最佳工艺为糖液：麸皮：稻糠砣=3：3，发酵温度43℃，醋酸菌接种量0．3％，枸杞液占糖液比例为20％。生产的果醋枣香浓郁，营养丰富。     

菊芋果醋发酵工艺研究

以菊芋为主要原料,经酒精发酵、醋酸发酵制得菊芋果醋.研究分析了菊粉酶添加量,醋酸菌接种量、发酵温度、初始pH、通风量对醋酸发酵的影响.试验结果表明:菊芋汁中菊粉酶的添加量为0.15％；醋酸发酵最佳发酵条件为菌种接种量10％,发酵温度36℃,初始pH 5,通风量250 r/min(以摇床转速计)；在最佳发酵工艺条件下醋酸发酵时间为168 h.     

一步发酵法加工柿果醋工艺参数优化

在传统自然发酵工艺基础上,为了缩短柿果醋发酵时间,以水柿为原料,采用二次正交旋转组合设计试验方案,通过响应面法研究只接种了酿酒活性干酵母的柿果醋的发酵规律及工艺参数.结果表明:发酵温度对醋酸含量有极显著的影响(P<0.01),酵母菌接种量对醋酸含量有显著影响(P<0.05).建立了柿果醋一步发酵过程中发酵温度、酵母菌接种量和发酵时间3个因素时产品醋酸含量的二次多项式数学模型.最佳工艺参数为发酵温度30.9℃、酵母菌接种量0.87‰、发酵周期178 h.验证试验表明该模型可用于指导实际生产.     

液体发酵猕猴桃醋的研究

该文研究确定了猕猴桃醋生产过程中酒精发酵的最佳工艺参数,发酵温度25℃,发酵周期72h,接种量5%。正交实验确定醋酸发酵的主要工艺参数,初始酒精度5%,pH5.5,醋酸菌接种量12%。醋酸发酵液经过滤直接作为调味品,也可以调配成不同风味的果醋饮料。     

液体发酵法制备油桃果醋的工艺优化

研究确定了油桃醋生产过程中酒精发酵的最佳工艺参数,即发酵温度25℃,发酵周期72h,接种量5%。正交试验确定了醋酸发酵的最佳工艺参数,即初始酒精度5%,pH5.5,醋酸菌接种量12%。醋酸发酵液经过滤可直接作为调味品,也可以调配成不同风味的果醋饮料。     

响应面法优化荔枝醋酸发酵的工艺条件

为研究荔枝醋酸发酵的最佳工艺条件,通过响应面分析优化方法,考察了醋酸菌接种量、温度、初始酒精度等三个因素对荔枝醋酸发酵液总酸含量的影响。结果显示,醋酸菌接种量对荔枝醋酸发酵的总酸含量影响极显著（P＜0.01）,发酵温度和初始酒度对荔枝总酸含量有显著影响（P＜0.05）。研究表明,荔枝醋酸发酵的最优工艺参数为发酵温度32 ℃,初始酒精度5.5%vol,醋酸菌接种量0.42 g/L。在此优化条件下,总酸产量为4.91 g/100 mL。     

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.