高能电子束辐照对草莓常温贮藏品质的影响

为提高草莓采后品质和延长保鲜时间,促进电子加速器在鲜活农产品保鲜方面的研究和应用,文中研究了0.5、2.0、3.5和5.0kGy不同剂量电子束辐照处理对丰香草莓常温贮藏性状的影响及微生物控制效果。结果显示:电子束辐照后常温(18-20℃)贮藏期间,2.0-3.5kGy辐照处理能够有效控制微生物的生长,使草莓保鲜期延长了2-6d(腐烂指数<0.3),且3.5kGy辐照对果实硬度、水分、糖、酸及Vc等贮藏品质的保持效果较好。5.0kGy辐照虽然能够有效抑制微生物的生长,但是对草莓营养品质有一定负面影响,可作为电子束辐照草莓的最高极限剂量。     

电子束辐照对即食凤爪品质的影响

以即食凤爪为试材,研究了电子加速器辐照处理对凤爪品质的影响,分析了不同剂量处理条件下凤爪的脂质氧化TBARS值、总挥发性盐基氮、弹性、汁液流失率、感官品质和菌落的变化情况。结果表明:当辐照剂量达到6.0 kGy时,产品贮藏180 d后其菌落总数为4 300 cfu/g,菌落总数电子束辐照的D10值在1.84～2.22 kGy;辐照剂量大于6.0 kGy时,TBARS值与空白相比有显著差异,而TVB-N则无显著差异;辐照剂量超过8.0 kGy时,则凤爪的弹性与汁液流失率有显著的影响。辐照剂量在一定范围内(8.0 kGy),对产品的感官品质不会产生明显的影响。常温下180 d的贮藏实验结果显示,采用电子束辐照可以显著降低并控制即食凤爪微生物含量,延长产品的货架期。     

电子束辐照对松花粉脂质氧化及其品质的影响

以原松花粉为试材,研究电子束辐照对其杀菌效果、脂肪酶活力、脂质氧化性能和营养品质的影响,并分析了破壁松花粉在加速氧化过程中色泽、过氧化值和挥发性成分的变化。结果表明,电子束辐照可显著降低松花粉中微生物含量,且辐照剂量越大,杀菌效果越显著;菌落总数、霉菌酵母数和大肠菌群的D10值分别为2.20、1.95和1.84 kGy;随着辐照剂量的增加,松花粉中脂肪酶活力、类胡萝卜素含量和游离脂肪酸含量显著降低,过氧化值略有升高但总体仍处于较低水平,当辐照剂量为8 kGy时,脂肪酶灭活率为53.52%,类胡萝卜素保留率为60.81%,游离脂肪酸含量为1.38 mg/kg,过氧化值为0.46 meq/kg;此外,8 kGy剂量辐照对松花粉的基本营养成分及氨基酸含量无明显影响,在加速氧化过程中,破壁松花粉的色泽无明显变化,过氧化值、己醛和己酸含量增幅不大。表明8 kGy电子束辐照对松花粉营养品质影响不大,并能有效杀灭微生物,抑制脂质氧化,提高产品储藏稳定性。     

电子束辐照对鲜牡蛎杀菌保鲜效果的影响

以新鲜牡蛎为材料,采用不同剂量电子束辐照,通过测定菌落总数、大肠菌群、T-VBN值及感官评分,评价电子束辐照对鲜牡蛎的杀菌效果及其冷藏保质期。结果表明:1)经1~9kGy剂量电子束辐照,鲜牡蛎的组织弹性几乎没有变化,而9 kGy剂量组产生明显异味;2)辐照剂量越高,杀菌效果越好。当鲜牡蛎的初始菌落总数为4.6×105CFU/g时,D10=2.22 kGy;1,3 kGy和5 kGy剂量电子束辐照对鲜牡蛎的抑菌效果明显,冷藏条件下的保质期由对照组的3 d分别延长到7,10 d和11 d。该结果可为电子束辐照应用于生食鲜牡蛎保鲜提供依据。     

电子束冷杀菌对即食鱿鱼丝保藏作用的研究

利用电子束处理即食鱿鱼丝,在贮藏期间对鱿鱼丝总挥发性盐基氮、过氧化值、酸价和菌落总数进行测定,分析不同剂量电子束对鱿鱼丝的杀菌效果及其保藏作用.结果表明:电子束处理后鱿鱼丝T-VBN值、POV、AV均有不同程度的增加,但随着贮藏时间的延长,对照组样品T-VBN值、POV、AV的上升速度大于辐照组样品;除色泽略有加深外,电子束处理时鱿鱼丝感官影响不明显;电子束处理能有效降低鱿鱼丝的菌落总数,其中D10=3.62kGy,D=8.98kGy.使用电子束处理鱿鱼丝能延长产品保质期.     

辐照对蚕蛹贮藏期品质特性的影响

以真空包装的蚕蛹为材料,经0、3、6 kGy 60Co-γ射线辐照后,在4 ℃条件下贮藏0～60 d,研究不同辐照剂量和不同贮藏时间（0、30、60 d）条件下蚕蛹的感官指标与品质的变化。结果表明：1）辐照蚕蛹的色度值、酸值、脂肪含量、微生物数量显著降低,硬度、咀嚼性、过氧化值显著升高;感官评分、蛋白质含量和弹性无显著变化。2）在贮藏期间,辐照蚕蛹的色度值、微生物数量随辐照剂量的增加而降低;硬度、咀嚼性、脂肪含量随剂量的增加而增加;过氧化值增加的幅度低于对照,且辐照剂量较高的处理增加幅度较为缓慢;酸值无明显变化。3）6 kGy辐照对蚕蛹具有显著的杀菌效果。由此可见,辐照改善了蚕蛹的贮藏品质,杀菌效果显著,有利于延长蚕蛹的保鲜期。     

电子束辐照的熟制鲢鱼块贮藏品质分析

该研究以熟制鲢鱼块为原料,使用0、4、8 kGy电子束辐照处理后,分别置于常温和4 ℃中贮藏,通过测定贮藏期间样品菌落总数（TVC）、pH值、硫代巴比妥酸值（TBA）、过氧化值（POV）、挥发性盐基氮值（TVB-N）与质构的变化,研究不同辐照剂量及贮藏温度对熟制鲢鱼块贮藏品质的影响。结果表明,辐照剂量越高对熟制鲢鱼块杀菌效果越好,4 ℃贮藏杀菌效果优于常温贮藏。贮藏温度对鲢鱼块pH值无明显影响,但8 kGy辐照处理会降低鱼块pH值（P<0.05）。鲢鱼块TBA值随着辐照剂量的增加而增加,但不同辐照剂量、不同贮藏温度之间无显著差异（P>0.05）。与未辐照组相比,电子束辐照能有效抑制鱼块POV值和TVB-N值的升高（P<0.05）。质构测定结果显示,当贮藏温度为4 ℃、辐照剂量为4 kGy时,可保持杀菌效果的同时改善熟制鲢鱼块的硬度、弹性和咀嚼性等指标。综合考虑,以4 kGy辐照剂量处理熟制鲢鱼块,并选择贮藏温度4 ℃,其保鲜效果最佳。以上研究可为鲢鱼电子束辐照贮藏保鲜技术的推广应用提供理论依据。     

浒苔多酚协同低剂量电子束辐照对鳗鱼鲞菌落总数和油脂氧化的作用

为筛选合适的多酚预处理保护措施以减缓低剂量电子束辐照处理鳗鱼鲞中油脂的氧化酸败,延长其贮藏期,本实验对比对照（CK）、3 kGy电子束辐照、0.15%浒苔多酚（Enteromorpha prolifera polyphenols,EPP）＋3 kGy电子束辐照和0.3% EPP＋3 kGy电子束辐照4 种不同预处理措施对在4 ℃条件下贮藏6 月的鳗鱼鲞菌落总数及油脂氧化过程的影响。通过对比不同预处理后鳗鱼鲞菌落总数和油脂的硫代巴比妥酸反应物值、酸价、碘价、过氧化值、p-茴香胺值、脂肪氧合酶活力的变化,确定适合低剂量辐照鳗鱼鲞的EPP预处理方法。结果表明,低剂量电子束辐照处理促进了鳗鱼鲞的油脂氧化,EPP能有效抑制电子束处理导致的油脂劣化进程,0.3% EPP＋3 kGy电子束辐照处理能够有效减缓贮藏期间鳗鱼鲞油脂的氧化进程,并对菌落总数增长有明显的抑制作用,在整个贮藏期内,菌落总数始终不高于0.2（lg（CFU/g））,延缓了鳗鱼鲞的品质下降,延长了其货架期。     

电子束辐照对丹棱冻粑杀菌效果及保质期的影响

以白糖味丹棱冻粑为试材,采用1、2、3、4、5、6 kGy剂量电子束辐照后贮藏在3±1℃条件下,对贮藏期内丹棱冻粑大肠菌群、菌落总数、霉菌进行测定,结合感官评价分析不同剂量电子束辐照对丹棱冻粑杀菌效果及保质期的影响。结果表明:当辐照剂量为3 kGy时,丹棱冻粑的大肠菌群(CFU/g)由初始的"400/300/450/400/500"降低到"10/10/10/10/10";当辐照剂量为4 kGy时,丹棱冻粑的霉菌(CFU/g)由初始的"350"降低到"10";当辐照剂量为5 kGy时,丹棱冻粑的菌落总数(CFU/g)由初始的"6 000/7 000/9 000/5 000/6 000"降低到"10/10/10/10/10";3、4 kGy剂量辐照处理丹棱冻粑后贮藏在3±1℃条件下,保质期分别为15、24 d;丹棱冻粑在3±1℃贮藏前采取3-4 kGy电子束辐照处理较为合适。     

酱鸭的辐照保质技术研究

为了研究酱鸭的常温非制冷保藏技术,以60Coγ射线辐照酱鸭真空包装制品。结果显示：采用6kGy辐照并于(25±0.5)℃条件下贮藏的产品保质期为90d,在贮藏期内既可以保证其微生物安全性,又对感官与营养价值无显著影响,TBA值相对较低。进一步对该产品先采用90～95℃、30min的巴氏低温二次杀菌作为预处理,再以6kGy辐照及(25±0.5)℃条件下贮藏,则保质期可延长至120d。     

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.