枯草芽孢杆菌在鱼片保鲜中的应用

目的:为以生物膜形成能力为筛选依据的枯草芽孢杆菌生物保鲜剂开发提供新思路。方法:测定枯草芽孢杆菌的疏水能力、自凝聚率、共凝聚率及生物膜形成能力，并利用枯草芽孢杆菌对冰鲜罗非鱼片进行保鲜，测定罗非鱼片的鲜度和挥发性风味物质。结果:枯草芽孢杆菌的生物膜形成能力越强，对罗非鱼肉的保鲜效果最佳。枯草芽孢杆菌可显著降低鱼肉中的挥发性盐基氮含量，使鱼肉在贮藏第3天的TVB-N含量为24.43 mg/100 g，低于对照组的34.58 mg/100 g；并且显著抑制鱼肉中醇类、酚类、酯类和酸类，如异戊醇、苯酚、吲哚、乙酸等挥发性风味成分的产生。同时，较生物膜形成能力而言，枯草芽孢杆菌的抑菌能力并未体现出与保鲜能力的相关性。结论:枯草芽孢杆菌的自凝聚和生物膜形成能力与其对罗非鱼片的保鲜能力最为相关，可作为保鲜用枯草芽孢杆菌筛选的快速指标。     

樟树叶多酚抑菌活性及在冷藏草鱼肉保鲜中的应用

为研究樟树叶多酚的抑菌活性及其对食品保鲜的效果,测定樟树叶多酚对7株常见致病菌、腐败菌的最低抑菌浓度、最低杀菌浓度,并研究其对冷藏草鱼肉菌落总数、pH值、挥发性盐基氮含量、三甲氨含量的影响。结果表明,樟树叶多酚对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、青霉、黑曲霉、毛霉等均有明显抑制作用,抑菌效果顺序为:荧光假单胞菌枯草芽孢杆菌金黄色葡萄球菌=大肠埃希菌青霉=黑曲霉=毛霉;最小抑菌浓度分别为0.500,0.625,1.250,1.250,2.500,2.500,2.500mg/mL;最小杀菌浓度分别为1.000,1.250,2.500,2.500,2.500,2.500,2.500mg/mL。新鲜草鱼肉添加5,10mg/g樟树叶多酚,可明显抑制冷藏草鱼肉中微生物生长,鱼肉pH值、挥发性盐基氮含量、三甲氨含量增加速度明显降低,使冷藏鱼肉货架期从3d分别延长至6,8d。樟树叶多酚可作为鱼肉保鲜用天然抑菌剂。     

脱脂对肉骨粉品质的影响

对脱脂前后肉骨粉的品质进行了分析.结果表明,脱脂后肉骨粉的风味和色泽明显改善,粗脂肪含量由9.80％下降到0.37％,粗蛋白含量由54.50％提高到61.20％,蛋白质体外消化率由86.01％提高到90.45％,酸值(KOH)由9.00 mg/g降到2.60 mg/g,挥发性盐基氮(TVB-N)含量由60.0 mg/100 g降到40.0 mg/l00 g,组胺含量由20.1 mg/kg降到19.6 mg/kg.脱脂显著提高了肉骨粉的品质.     

山西老陈醋优良芽孢菌与醋酸菌、乳酸菌的相互作用

对分离自山西老陈醋酿造过程中的54株芽孢菌产乙偶姻、多酚、酯及不挥发性酸性能进行测定,结果显示解淀粉芽孢杆菌1539产多酚(750.96μg/mL)及不挥发性酸(2.93 g/L)的能力最强,枯草芽孢杆菌803产乙偶姻和酯的性能最强,分别为0.92 mg/mL和9.63 g/100 mL。将二者以体积比为1∶10的接种比例进行共培养,乙偶姻、多酚、总酯及不挥发性酸含量显著高于纯培养,分别为3.65 mg/mL,197.52μg/mL,8.79 g/100 mL,8.26 g/L;其中,草酸、丙酮酸、酒石酸和乳酸几种食醋中主要的不挥发性酸,分别提高了89.78%,88.32%,22.92%,32.98%,并且挥发性香气的种类和含量也显著高于纯培养。再将解淀粉芽孢杆菌1539和枯草芽孢杆菌803(体积比为1∶10)与巴氏醋杆菌33、植物乳杆菌19等体积比例接种进行共培养,结果表明多种菌株共培养下的乙酸乙酯、异戊酸乙酯、1-辛烯-3-醇、癸醛等山西老陈醋的特征挥发性香气成分含量显著高于各菌株纯培养。本试验为山西老陈醋发酵专用复配菌剂的开发提供了基础研究数据支持。     

混合菌固态发酵豆粕制备大豆活性肽

以枯草芽孢杆菌(Bacillus subtilis J3)和植物乳杆菌(Lactobacillus plantarum JNX)为发酵菌株,以发酵产物中小肽含量和挥发性盐基氮含量为检测参数,优化了混合菌固态发酵豆粕以制备大豆肽的生产工艺参数,并对发酵产生的大豆肽的性质进行了初步研究。确定的固体发酵工艺为:植物乳杆菌和枯草芽孢杆菌菌种比例为2∶1、料水比1∶0.6、接种量6%、30℃发酵24 h,该条件下发酵产物中小肽含量最高为10.64%,挥发性盐基氮含量最低为50.70 mg/100 g。SDS-PAGE电泳结果表明,发酵后豆粕提取液中的蛋白类产物的分子质量均为10k Da以下,其抗氧化活性最高可达65.76%。氨基酸组成成分分析表明,混合菌固态发酵豆粕后的提取液中甲硫氨酸、亮氨酸、缬氨酸、苯丙氨酸和异亮氨酸等必需氨基酸的含量提高了5倍以上。     

两种微生物水解脱淀粉小麦中蛋白效果的比较研究

为研究枯草芽孢杆菌（Bacillus subtilis）和米曲霉（Aspergillus oryzae）对脱淀粉小麦中蛋白质的水解效果,采用前发酵和后发酵获得发酵液,比较两种微生物培养过程中性蛋白酶活力和发酵液的pH值、可溶性无盐固形物、氨基酸态氮含量、氨基酸组成,并对其发酵液进行感官评价。结果表明,在最适前发酵工艺的条件下,枯草芽孢杆菌和米曲霉中性蛋白酶活力分别为1 060.82 U/g和908.02 U/g;两种微生物最终发酵液pH值为7.08和5.37,可溶性无盐固形物为15.60%和18.98%,氨基酸态氮含量为0.73 g/100 mL和0.75 g/100 mL,总游离氨基酸含量为4.35 mg/mL和9.04 mg/mL,蛋白质水解度为55.99%和59.71%。枯草芽孢杆菌发酵液中必需氨基酸的组成和比例更符合氨基酸模式谱,必需氨基酸与总游离氨基酸的比值（EAA/TAA）、必需氨基酸与非必需氨基酸（EAA/NEAA）的比值也高于米曲霉。感官评价结果显示,米曲霉发酵液好于枯草芽孢杆菌。     

双菌株联合固态发酵冷榨核桃粕提高产品纳豆激酶活性的研究

为提高纳豆芽孢杆菌单菌发酵品的纳豆激酶(nattokinase,NK)活性并减少产品的不良氨味,采用戴尔凯氏有孢圆酵母、植物乳杆菌分别与纳豆芽孢杆菌联合固态发酵核桃粕。结果表明:纳豆芽孢杆菌与戴尔凯氏有孢圆酵母在接种量3%、菌种配比2∶1、发酵温度34℃、发酵时间60 h的条件下得到的核桃粕发酵品NK活性达2040.82 U/g,提高了70.42%,挥发性盐基氮含量为64.18 mg/100 g,降低了84.37%;纳豆芽孢杆菌与植物乳杆菌在接种量9%、菌种配比1.5∶1、发酵温度42℃、发酵时间60 h的条件下得到的发酵品NK活性为1966.02 U/g,提高了64.18%,挥发性盐基氮含量为62.68 mg/100 g,降低了84.74%。混合菌种发酵品的氨味显著减少,改善了传统发酵品的风味。     

风干肠加工和贮藏过程中蛋白质的降解规律

以总氮、非蛋白氮、氨基酸态氮、挥发性盐基氮、游离氨基酸以及不同种类蛋白质（肌浆蛋白、肌原纤维蛋白、碱溶蛋白和碱不溶蛋白）为指标,分析研究风干肠加工和贮藏过程中蛋白质的降解规律。结果表明：风干肠加工和贮藏过程中总氮含量没有显著变化;非蛋白氮含量持续升高,从原料肉的469.4 mg/100 g增加到成品肠的786.4 mg/100 g,贮藏240 d后增加至1 256.1 mg/100 g;多肽氮和氨基酸态氮含量在加工和贮藏过程中均持续增加,挥发性盐基氮含量在风干过程中没有显著变化,在贮藏180 d后迅速增加;大部分游离氨基酸含量经过加工和贮藏均有所提高,只有半胱氨酸含量明显降低;在加工过程中,肌浆蛋白和肌原纤维蛋白含量均因降解而减少,基质蛋白含量明显增加;在贮藏过程中,肌浆蛋白含量持续降低,肌原纤维蛋白含量在贮藏前180 d无明显变化,贮藏至240 d明显减少,基质蛋白含量没有显著变化。     

枯草芽孢杆菌腐乳发酵过程中主要成分的变化

考察了不同温度条件下枯草芽孢杆菌在腐乳中的生长情况,并对腐乳在发酵过程中的蛋白、脂肪、游离脂肪酸、氨基态氮的含量变化进行了研究。结果表明:枯草芽孢杆菌在35℃左右生长良好,2天左右即可生长成熟。腐乳后酵7周后,蛋白含量由后酵起始的25.7g/100g缓慢降解到20.1g/100g;脂肪含量先是缓慢上升,后酵2周后稳定到24.5g/100g左右;游离脂肪酸含量总体呈降低趋势,达到6.4g/100g;游离氨基酸含量后发酵5周就可达到1.51g/100g,达到腐乳成熟的标准。     

宣恩火腿蛋白质降解规律

分析测定了宣恩火腿从原料腿到成品的整个加工过程中蛋白质的变化情况,结果显示:宣恩火腿中非蛋白氮含量从原料腿中的685.9 mg/100 g增加到成品的1724.3 mg/100 g,非蛋白氮中的多肽氮在整个加工周期内持续上升,发酵末期上升幅度更大,氨基酸态氮含量在发酵中前期快速升高,末期略有下降,挥发性盐基氮含量变化规律跟氨基酸态氮一致。呈味氨基酸含量在整个加工过程中上升明显,从315.8 mg/100 g增加到2171.3 mg/100 g,其中鲜味较强的谷氨酸含量增加了29.6倍。宣恩火腿各蛋白质中,肌浆蛋白和肌原纤维蛋白均由于降解而含量下降,特别是在发酵中后期降幅更大,肌浆蛋白比肌原纤维蛋白降解更彻底。肉基质蛋白含量在发酵初期由于蛋白质的热变性而升高,随后保持稳定。总而言之,蛋白质的水解伴随着整个宣恩火腿的加工过程,尤其是在发酵中后期,这种水解程度更为明显,为火腿特有风味的形成产生重要作用。     

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.     

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.     

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.     

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.