植物精油对水产品中常见微生物的抑制效应

研究植物精油对水产品中常见腐败致病微生物的抑制效果。采用滤纸片法测定植物精油的抑菌圈直径,筛选出3种效果较佳的精油;然后运用试管梯度稀释法测定精油对供试菌的最低抑菌浓度(MIC);采用棋盘稀释法对3种精油的联合抑菌活性进行了研究,并以FICI值对效果进行评价。通过抑菌圈的测定,筛选出肉桂精油、紫苏精油、丁香精油,各精油对供试菌的MIC值范围分别为:0.313~0.625,0.625~2.50,0.625~2.50μL/mL。棋盘稀释法结果表明复配精油对6种供试菌都显示出了协同或相加作用,不存在无关作用和拮抗作用。     

肉桂、紫苏精油对青霉和黑曲霉抑菌特性研究

以冬枣中常见致病菌青霉(Penicilliumsp.)和黑曲霉(Aspergillusniger)为控制对象,通过单因素和正交试验研究不同复配比、不同处理温度和pH条件下肉桂精油和紫苏精油对这两种霉菌的抑制效果。结果表明:(1)肉桂精油对青霉和黑曲霉的最小抑菌浓度(MIC)分别为:0.313μL/mL和0.156μL/mL;紫苏精油对青霉和黑曲霉的MIC分别是10μL/mL和5μL/mL;(2)肉桂精油与紫苏精油在总含量为0.42μL/mL,复配比为3∶1,处理温度为5℃和pH为3时抑菌效果最好,对青霉和黑曲霉的最大抑菌圈直径可高达24mm和22.7mm。说明复配精油对青霉和黑曲霉均有明显的抑制作用,是一种良好的冬枣贮藏霉菌抑制剂。     

肉桂精油复配香芹酚和百里香酚对食用畜禽有害微生物熏蒸的抗菌活性

通过测定抑菌圈直径确定肉桂精油及单离香料香芹酚和百里酚对食用畜禽有害微生物的敏感性,同时采用气相熏蒸法测定最低抑菌浓度（Minimum Inhibitory Concentration,MIC）和最低杀菌浓度（Minimum Bacterial Concentration,MBC）。结果表明：肉桂精油及香芹酚和百里酚对食用畜禽有害微生物都具有一定的抑杀能力。肉桂精油对黑曲霉的抗菌效果优于百里香酚和香芹酚,肉桂精油对黑曲霉的MIC和MBC为62.5 μL/L,而百里香酚和香芹酚的MIC和MBC均为125 μL/L;将肉桂精油与香芹酚进行复配,复配精油对白色葡萄球菌和黑曲霉均表现出相加作用（FICI≤1）,而对白色念珠菌则表现为无关作用。通过GC-MS分析,肉桂精油的主要挥发性化学成分中相对含量较高的为肉桂醛（78.19%）、2-甲氧基肉桂醛（8.70%）。采用电子鼻分析溶剂稀释后对复配精油抑菌活性的影响,抑菌能力大小为：丙二醇稀释≈无水乙醇稀释＞未稀释＞甘油稀释＞食用油稀释。实验表明：香芹酚与肉桂精油复配可以提高肉桂精油的抗菌活性,溶剂挥发性的差异会对复配精油的抑菌活性造成不同影响,稀释复配精油时溶剂的较优选择为丙二醇。     

甜橙精油的化学成分、抑菌和抗氧化活性研究

采用气相色谱-质谱法(GC-MS)对甜橙精油的挥发性成分进行分析,通过抑菌圈实验和试管二倍稀释法对其抑菌效果、最低抑菌浓度(MIC值)进行测定,采用3种方法(DPPH、ABTS和FRAP)对甜橙精油的抗氧化活性进行体外评价。结果表明:甜橙精油含有101种组分,鉴定出50种成分,主要为脂肪族(5.96%)和萜类化合物(78.39%);甜橙精油对6种供试菌均有较明显的抑制作用,其中对枯草芽孢杆菌的抑制作用最强(MIC值7.5μL/m L),绿色木霉最弱(MIC值15μL/m L);甜橙精油对DPPH自由基和ABTS+自由基有明显的清除作用,样品量与清除率间呈量效关系。     

复合精油对黄曲霉联合抑菌作用研究

采用联合抑菌评价方法,通过测定植物精油抑菌圈直径、最低抑菌浓度(Minimum Inhibition Concentration,MIC)、最低生长下降浓度(Reduction Concentration,RC)、联合抑菌指数(Fractional Inhibitory Concentration,FIC),对植物精油单独及联合使用后的抑菌效果进行评价,筛选最佳抑制黄曲霉活性作用的复合精油种类及配比。结果表明:大蒜、肉桂、丁香、薄荷精油单独或复合使用均有较强抑制黄曲霉活性的作用。大蒜与肉桂精油联合抑菌评价为相加作用。当大蒜精油与肉桂精油复合体积比为1∶3时,复合精油具有最佳抑制黄曲霉活性的效果。因此,复合精油作为有效防霉保鲜成分具有良好的研发与应用前景。     

11种精油对三种水产品特定腐败菌的抑制

通过抑菌圈、平板稀释法、气相扩散法等体外抑菌试验研究了11种精油对三种常见的水产品特定腐败菌(Specific spoilage organism,SSO)的抑制效果。结果表明:百里香和牛至精油的抑菌效果较好,对三种供试SSO的固相最低抑菌浓度(Minimum inhibitory concentration,MIC)均为0.3125μL/mL,对荧光假单胞菌与副溶血性弧菌的气相MIC为0.0625μL/mL,腐败希瓦氏菌的MIC为0.0313μL/mL。丁香精油在固相试验中有很好的抑菌效果,对三种菌的MIC不大于1.25μL/mL,但气相抑菌效果较差,对荧光假单胞菌与副溶血性弧菌的MIC>2μL/mL。     

复合香辛料精油对冷却猪肉中单核增生性李斯特菌的抑制作用

利用超临界CO2萃取丁香、肉桂及黑胡椒精油,研究三种精油对单核细胞增生性李斯特菌的抑制作用,并将复合精油应用于冷却猪肉保鲜。结果表明:三种精油对单增李斯特菌都有较强的抑制作用,黑胡椒精油的抑菌能力最强,最低抑菌浓度为48 mg/L,肉桂和丁香分别为72 mg/L和96 mg/L;通过正交实验确定最优复合精油菌比例,即丁香精油∶肉桂精油∶黑胡椒精油为3∶2∶2;复合精油MIC值为16 mg/L,精油复配产生相加作用,使复合精油的抑菌效果增强;复合精油对冷却肉中的单增李斯特菌具有抑制作用,可以延长冷却猪肉的保鲜期。     

基于Modified Gompertz研究食品模型中肉桂精油的抑菌活性

香辛料精油可以有效地抑制微生物生长,延缓食品腐败变质,但体内应用时其抑菌活性常受到食品成分的影响。本文以最低抑菌浓度(MIC)和抑菌圈直径(DIZ)为指标,发现肉桂、丁香、大蒜、生姜、百里香、鼠尾草、迷迭香、芥末和牛至9种香辛料精油中肉桂精油是对大肠杆菌和金黄色葡萄球菌抑菌活性均最高的精油,MIC分别为250μL/L和500μL/L,DIZ分别为31.8±1.7 mm和30.5±0.5 mm。通过Modified Gompertz生长模型,研究肉桂精油在蛋白质和碳水化合物两类食品模型中对两种受试细菌延滞期(λ)和最大比生长速率(μmax)的影响。结果显示:蛋白质和碳水化合物对肉桂精油抑菌活性均有加强作用;大肠杆菌在牛肉和马铃薯模型(含有1/4MIC肉桂精油)中的λ较Luria-Bertani培养基分别延长1.76倍和2.51倍;同样模型中,金黄色葡萄球菌在24 h内生长完全受到抑制。上述结果表明肉桂精油具有在蛋白质或碳水化合物成分高的食品中推广应用的潜力。     

药食两用植物提取液对李果实采后常见致腐真菌抑制作用

采用滤纸片法比较七种植物提取液对李果实采后常见致腐真菌的抑菌效果,研究甘草和肉桂复合提取液对褐腐病菌（Monilinia fructicola）的抑制效果及抑菌机理。结果表明,1.0g/mL甘草提取液对褐腐病菌抑制作用最强,抑菌圈直径为12.03mm;1.0 g/mL肉桂提取液对酵母菌（Saccharomyces）、黑曲霉（Aspergillus niger）、米曲霉（Aspergillus oryzae）抑制作用最强,抑菌圈直径分 别为21.25 mm、17.49 mm和13.28 mm。 甘草、肉桂提取液对褐腐病菌的最小抑菌浓度（MIC）值分别为7.81 mg/mL、15.63 mg/mL,两者 联合使用时对褐腐病菌的分级抑菌浓度（FIC）值为0.75,抑菌效果增强。 甘草、肉桂提取液处理后的褐腐病菌培养液相对电导率分别 达到96.64%、48.47%;可溶性蛋白质含量分别达到50.6 μg/mL、25.1 μg/mL。 推测其破坏了褐腐病菌细胞膜结构,改变了细胞膜渗透性,导致细胞质外泄,从而发挥抑菌作用。     

不同植物精油对大米青霉和黑曲霉的抑菌效果

为探明部分植物精油对大米的防霉效果,选取提自蓝桉叶、薄荷、山苍子、孜然、丁香、肉桂、花椒、香茅以及迷迭香的9种精油为研究对象,以大米青霉和黑曲霉为目标菌,通过测定抑菌圈直径、最小抑菌浓度、最低生长下降浓度和联合抑菌效果,以确定单一精油的抑菌效果、复配精油的协同抑菌效果及其最佳配比。结果表明,在所选9种精油中,肉桂和丁香精油对大米青霉和黑曲霉的抑菌效果最好,山苍子和蓝桉叶精油次之。在两两复配精油中,当肉桂精油与山苍子精油的比例为3:1(v/v)时,对大米青霉和黑曲霉的抑制效果最佳,其最小抑菌浓度为0.1 μL/mL,比单一精油的浓度下降了20~180倍。研究表明按适当比例复配的肉桂与山苍子复合精油是具良好应用前景的大米防霉保鲜剂。     

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.     

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.     

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.     

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.     

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 on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.