两种包装材料结合真空贮藏对油炸脆枣货架期的预测

为探究低温油炸脆枣贮藏过程中品质劣变规律,采用PET真空包装、PET真空+脱氧剂包装、铝箔真空包装、铝箔真空+脱氧剂四种包装方式,分析不同贮藏温度(25、35、45℃)下酸价和过氧化值的变化,结合Arrhenius公式建立低温油炸脆枣货架期的预测模型。结果表明：不同贮藏温度下四种包装方式的油炸脆枣的酸价、过氧化值呈上升趋势,25℃变化速率低。从包装效果来看,铝箔真空+脱氧剂包装方式油炸脆枣的氧化速率最低(酸价动力学模型K值=0.0131,过氧化值动力学模型K值=0.0147),预测货架期模型R2>0.90,拟合度良好,货架期预测值模型误差小于10%。通过比较不同包装方式真空低温油炸脆枣的品质变化,铝箔真空+脱氧剂包装效果最佳,该包装方式下常温贮藏60 d,酸价上升了0.322 mg/g,过氧化值上升了0.026 g/100 g,预测货架期达180 d。     

油炸裹糊牡蛎贮藏品质的变化与货架期预测

为探讨油炸裹糊牡蛎的货架寿命,以感官评分、pH、挥发性盐基氮（total volatile basic nitrogen, TVB-N）含量、菌落总数为指标,研究在4、15、25 ℃下贮藏的油炸裹糊牡蛎的品质变化规律,建立并验证油炸裹糊牡蛎在4～25 ℃贮藏温度下的货架期预测模型。结果表明:随贮藏时间的延长,油炸裹糊牡蛎的感官评分不断下降,pH呈先下降后上升的趋势,TVB-N含量和菌落总数不断增加,且贮藏温度越高,变化越快。感官评分与TVB-N含量的相关性较pH与菌落总数的高,以TVB-N含量作为关键品质指标,建立的油炸裹糊牡蛎货架期预测模型预测的货架期相对误差小于6%,可用于快速准确地预测4～25 ℃贮藏温度下油炸裹糊牡蛎的货架寿命。     

香菇牛肉酱贮藏过程中品质变化及动力学模型构建

以香菇牛肉酱为对象,分析不同贮藏温度下香菇牛肉酱的感官品质、酸价和过氧化值的变化规律,在Arrhenius动力学方程的基础上,建立感官品质、酸价和过氧化值与贮藏温度之间的动力学模型。结果表明:随着贮藏时间的延长,香菇牛肉酱的感官品质逐渐下降,酸价和过氧化值逐渐上升。将酸价作为指标,建立动力学模型可预测香菇牛肉酱的货架期,模型的活化能(E_a)和回归系数(K_0)分别为23 627.556 6 J/mol和48.623 2。经验证,此动力学模型可快速预测贮藏温度在25℃和35℃贮藏条件下香菇牛肉酱的货架期,误差在±5.0%以内。     

核桃坚果贮藏期品质变化动力学模型及货架期预测

为了研究核桃坚果在贮藏中脂肪氧化的动力学规律及其货架期预测模型,本研究通过将核桃坚果贮藏在0、10、20、30℃条件下,测定了核桃坚果的感官指标、酸价与过氧化值指标的变化。在Arrhenius动力学方程基础之上,建立了酸价、过氧化值与贮藏时间及贮藏温度之间的动力学模型。试验表明,随着贮藏时间的延长,核桃感官指标得分不断降低,且随温度的升高而迅速降低;与此同时,随着贮藏时间的延长,质量指标酸值和过氧化值不断增加,且随温度升高而迅速增加。酸价和过氧化值的变化规律符合一级化学反应动力学模型,对Arrhenius方程也有很高的拟合精度(≥0.9),以此建立的山核桃货架期预测值准确率在±10%以内,可通过酸价、过氧化值指标变化对0~30℃范围内的核桃坚果货架期进行预测。     

发芽糙米百香果曲奇饼干贮藏品质变化及货架期预测

以发芽糙米百香果曲奇饼干为研究对象,分析不同温度贮藏期间饼干过氧化值和酸价的变化规律。采用加速货架期试验法结合Arrhenius方程,建立过氧化值和酸价及贮藏温度间的动力学模型,并预测产品货架期。结果表明:随着贮藏时间的延长和贮藏温度的升高,饼干过氧化值和酸价均呈现上升趋势,饼干品质逐渐降低。以过氧化值和酸价为指标,在25℃贮藏下饼干货架期预测值分别为133 d和201 d。     

糊辣牛肉在不同温度条件下的贮藏特性及其货架期预测

以糊辣牛肉为实验材料,研究其不同贮藏温度条件下的贮藏特性和贮藏期间各品质指标的Pearson相关系数,建立了货架期预测模型。结果表明:贮藏期间产品pH值先降后升,伴随着菌落总数、TVB-N值和TBA升高,感官品质和硬度下降;贮藏温度越低,产品品质保存越好,货架期越长;在5℃、15℃、25℃、37℃和45℃货架期分别为16.0 d、12.5 d、8.5 d、3.0 d和1.5 d;不同温度条件下菌落总数与感官品质、pH、TVB-N、TBA和硬度均呈极显著相关(p0.01);依据贮藏特性的动态变化,开发出多元回归模型、温度与货架期关系回归模型和tTVB-N、tTVB-N和tHardness动力学货架期模型。通过模型验证发现,温度与货架期关系模型能快速有效预测5℃~25℃范围内方便菜肴糊辣牛肉货架期,相对误差范围为0.29%~2.36%;5℃~37℃范围内多元回归模型预测效果较佳,相对误差范围为1.07%~7.89%;tTVB-N、tTVB-N和tHardnes动力学货架期模型预测效果较差。     

冷却猪肉货架期预测模型建立及验证

建立针对不同贮藏温度下冷却猪肉的货架期预测模型,为猪肉贮藏和物流过程中品质评价、货架期预测提供技术支持。分析了0,2,4,6,8,10℃不同贮藏温度下猪肉的挥发性盐基氮(TVB-N)、pH值、色差(a*)、水分活度(Aw)与感官评定结果的相关性,利用一级反应动力学方程和Arrhenius方程求得TVB-N变化反应的活化能(E0)为87.19 kJ/mol,指前因子(k0)为2.169×1014,速率常数k为2.169×1014e-87190/RT,在此基础上建立了以TVBN为指标的冷却猪肉货架期预测模型。在0,4,8,10℃贮藏条件下对TVB-N预测模型进行验证,相对误差均小于10%,准确度和偏差度均为1.03,在可接受范围内。TVB-N是预测冷却猪肉货架期的有效指标,用其建立的货架期预测模型准确实用。     

不同贮藏温度下两种发酵香肠品质变化及货架期预测模型的建立

对玫瑰低硝半干发酵肠（M）和传统半干发酵肠（P）在3个温度（4、25、35 ℃）贮藏过程中的品质变化进行了评价,并运用动力学和Arrhenius方程建立了两种发酵肠货架期预测模型。研究表明,温度对两组香肠的红度值和质构特性影响较大,在贮藏期间,各贮藏温度下的酸价、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值和菌落总数( total viable count,TVC)随贮藏时间推移而升高,且温度越高变化越快;以TVB-N值和TVC为关键因子建立动力学模型,并结合Arrhenius方程构建两种发酵肠的货架期预测模型,P发酵肠的TVB-N值和TVC预测模型中活化能E_a分别为52.37 kJ/mol和43.39 kJ/mol,指前因子k₀分别为69859734.72、8806494.34;M发酵肠的TVB-N值和TVC预测模型中活化能E_a分别为46.46 kJ/mol和43.53 kJ/mol,指前因子K₀分别为5373553.61和8016399.99。选取4、30 ℃验证模型可靠性,两种发酵肠货架期理论值与实测值的相对误差在11.18%以内,可准确预测4～35 ℃范围内的货架期。此外,在不同贮藏温度下M发酵肠的品质均优于P发酵肠,并具有较长的保质期限。     

滚筒催化红外—热风联合干燥核桃的贮藏特性

以酸价和过氧化值为评价指标,研究不同贮藏温度和时间下核桃氧化酸败反应动力学过程,建立评价不同贮藏温度下核桃货架期的预测模型。结果表明,干燥处理后核桃贮藏期间酸价和过氧化值均随贮藏时间的延长而不断升高。变温滚筒催化红外—热风联合干燥处理的核桃酸价和过氧化值增幅最小,贮藏90 d后酸价为1.27 mg/g,过氧化值为0.019 9 g/100 g,其次是恒温滚筒催化红外—热风联合干燥核桃,最高的为单一热风干燥核桃,但均未超过国家规定标准,且品质良好。核桃的氧化酸败反应符合一级化学反应动力学模型。此外,分别以酸价和过氧化值建立了变温滚筒红外—热风联合干燥核桃的货架期预测模型,其R²＞0.99,相对误差＜9%,表明该预测模型在5~35 ℃内可较好地预测核桃的货架期。     

微波处理后坛子肉在不同温度下产品的贮藏特性及其货架期预测

以坛子肉半成品为试验材料,经2450MHz,12kW的微波设备在80℃进行杀菌3min后,探究不同贮藏温度(4℃,10℃,25℃,37℃)对贮藏期间坛子肉的感官品质、pH值、挥发性盐基氮、过氧化值、菌落总数的的影响及指标间的相关性,结合回归方程及方差分析构建货架期预测模型。结果表明:贮藏温度与感官品质、挥发性盐基氮、过氧化值、菌落总数相关性极显著;经温度和货架期预测回归方程求出在4℃,10℃,25℃和37℃下货架期分别为422.15d、374.43d、255.14d和159.70d,经验证预测货架期和实际货架期间相对误差为1.87-8.53%,该货架期预测模型效果优良。     

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.