不同体积分数CO_2对气调冷藏带鱼品质的影响

在(4±1)℃冷藏条件下,采用40%CO2+10%O2+50%N2、60%CO2+10%O2+30%N2、80%CO2+10%O2+10%N2含不同体积分数CO2气调包装带鱼。以感官评分、细菌总数、挥发性盐基氮(TVB-N值)、pH值、硫代巴比妥酸(TBA值)和汁液流失率为指标,研究不同体积分数CO2气调包装带鱼在冷藏条件下品质的影响。结果表明,气调包装能够有效抑制细菌的生长繁殖,延缓挥发性盐基氮的上升,高体积分数的CO2抑菌效果较为明显,但随CO2体积分数升高,鱼样汁液流失严重;在抑制鱼样脂肪氧化方面,气调包装效果不明显。80%CO2+10%O2+10%N2气调包装能够显著延长新鲜带鱼的保鲜期至14d以上。     

气调小包装对冷鲜人工养殖大鲵分割肉货架品质的影响

研究了气体成分对气调小包装冷鲜大鲵分割肉的品质影响。共有6组不同的气体成分,分别是:0%O2+70%CO2+30%N2;10%O2+70%CO2+20%N2;20%O2+60%CO2+20%N2;30%O2+60%CO2+10%N2;10%O2+50%CO2+40%N2;21%O2+0%CO2+79%N2。结果表明:10%O2+70%CO2+20%N2比例的气体成分保鲜效果最好,可有效延缓大鲵肉的色泽下降及汁液流失率与挥发性盐基氮含量的升高,抑制微生物的生长繁殖,使大鲵肉保持较高的感官品质,贮藏到第22天时,感官分值与色泽仍较高,分别为10分和51.2,汁液流失率、TVB-N值及菌落总数则较低,分别为5.4%、25.7 mg/100 g和4.6×105CFU/g。     

冰温条件下贮藏军曹鱼最佳气调包装参数的研究

在冰温下贮藏,研究不同的包装条件对军曹鱼品质的影响,确定冰温气调包装军曹鱼最佳气调包装参数。对照组为空气贮藏,实验组气体配比为6组,分别为100%N2、75%N2+25%CO2、50%N2+50%CO2、30%N2+65%CO2+5%O2、25%N2+75%CO2、100%CO2,包装袋以纯PE、一般阻隔性、高阻隔性3种材质的包装材料为对象进行研究,气调包装后在冰温袋-1.01~0℃范围内贮藏,贮藏期间考察K值、挥发性盐基氮(TVB-N)含量、细菌总数和汁液流失率等品质指标的变化。结果表明,K值、TVB-N含量、细菌总数、汁液流失率均在贮藏期间有不同程度的增加,并且对照组和实验组有显著性差异(p<0.05),以K值、TVB-N含量、细菌总数增长速度慢,汁液流失率少为评定标准,综合比较几种品质指标的变化规律,最终确定为使用高阻隔性包装袋并充以50%N2+50%CO2的气体配比进行冰温气调包装军曹鱼为最佳。     

复合生物保鲜剂结合气调包装对海湾扇贝柱冷藏保鲜效果的研究

本文以海湾扇贝柱为对象,采用复合生物保鲜剂及保鲜剂结合气调包装处理,测定其在(0±1)℃冷藏过程中菌落总数、理化和感官等指标的变化,评价复合生物保鲜剂结合气调包装的保鲜效果。结果表明:各处理组的挥发性盐基氮、细菌总数、感官评分、pH、Ca2+-ATPase活性变化均与贮藏时间相关(P0.05)。空气包装组海湾扇贝柱冷藏货架期为4 d,复合生物保鲜剂处理的货架期大约为9 d;生物保鲜剂结合气调包装能够显著延长冷藏扇贝货架期,具有良好的抑菌保鲜作用,高体积分数的CO2抑菌效果较为明显,但随CO2浓度升高汁液流失严重;生物保鲜剂结合80%CO2+20%N2气调包装组冷藏贮存10 d,海湾扇贝柱的菌落总数为5.20lg(cfu/g),TVB-N值为0.12 mg/g,Ca2+-ATPase活性为0.0310μmol Pi/(mg·h)。总体结果表明,复合生物保鲜剂结合气调包装能有效延长冷藏海湾扇贝柱的货架期。     

冷藏物流过程中不同气调包装对三文鱼品质的影响

为研究3种不同体积分数CO2(50%CO2+50%N2,60%CO2+40%N2及70%CO2+30%N2)的气调包装对存在温度波动的冷藏物流链中三文鱼品质保持的作用,通过测定冷藏物流过程中三文鱼的感官评分、红度值、p H、菌落总数、TVB-N值及K值的变化情况,分析不同体积分数CO2对三文鱼肉品质的影响。结果表明,不同体积分数CO2的气调包装对冷藏物流中温度变化导致的三文鱼品质下降均有减缓作用,其中气体比例为70%CO2+30%N2的气调包装的效果最好。70%CO2的气调包装能够使三文鱼肉维持较低的TVB-N值,同时能抑制微生物的繁殖,保证三文鱼在贮运末期仍有良好的品质。因此,在冷藏物流链中出现温度波动的情况下,采用气调包装能够有效减缓三文鱼肉品质的下降。     

不同气调包装条件下冷却猪肉贮藏过程中的品质变化

研究不同CO2、O2、N2气体组分配比的气调包装条件对气调包装冷却猪肉品质的影响,对6组在不同气调组分条件下,冷却猪肉在7d冷藏期内的菌落总数、挥发性盐基氮(TVB-N)值、脂肪氧化值(TBA)、感官指标进行监测。结果表明:不同气调保鲜条件下冷却猪肉贮藏过程中的品质变化显著;气调包装组分为40%CO2+40%O2+20%N2时,冷却猪肉的菌落总数未达到腐败水平,TVB-N值、TBA值均符合新鲜肉的标准,可作为优选气调保鲜条件用于实际肉类贮藏。     

几种栅栏因子在即食海蜇保鲜中的应用研究

通过对即食海蜇样品感官评定以及测定样品中肉毒梭状芽孢杆菌、菌落总数、TVB-N值、汁液流失率作为评价指标,研究温度、pH、包装方式等物理栅栏因子对即食海蜇保鲜的影响。盐矾海蜇经前处理后,分别采用普通包装、真空包装以及各种不同气体比例的气调包装（A：60%CO2/40%N2、B：60%CO2/35%N2/5%O2、C：60%CO2/30%N2/10%O2、D：50%CO2/45%N2/5%O2、E：50%CO2/40%N2/10%O2、F：40%CO2/55%N2/5%O2、G：40%CO2/50%N2/10%O2）后,分别在3℃、室温贮藏。实验结果表明：所有样品在保藏期间均没有肉毒梭状芽孢杆菌的检出;低温结合气调包装D处理可以明显延长即食海蜇制品的保质期,其保质期是常温贮藏A处理样品的1.5倍;用不同浓度柠檬酸溶液（Ⅰ：1%、Ⅱ：0.5%、Ⅲ：0.1%）浸泡处理结合气调包装D处理的即食海蜇样品,其中0.5%、1%柠檬酸浸泡处理的样品,分别在3℃低温贮藏56d后,海蜇质构变软,感官不可接受。0.1%柠檬酸浸泡处理过的样品,在贮藏70d后,感官评分较高,TVB-N值3.6152mgN/100g,菌落总数为2.85×104cfu/g。     

低温结合气调包装处理对鲜切胡萝卜品质的影响

该研究以鲜切胡萝卜为对象,采用低温结合气调包装对鲜切胡萝卜进行处理,研究不同保鲜方式对鲜切胡萝卜品质的影响。鲜切胡萝卜经气调(气体组成分别为5%O2+5%CO2+90%N 2、5%O2+10%CO2+85%N 2、10%O2+5%CO2+85%N 2)包装后,(4±1)℃下在保鲜盒中贮藏,每3 d测定感官品质、失重率、可溶性固形物含量、抗坏血酸含量、胡萝卜素含量、菌落总数、丙二醛(malondialdehyde,MDA)含量和以及超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性等指标。结果表明,低温结合5%O2+10%CO2+85%N 2气调包装处理组有效地保持了鲜切胡萝卜的品质,减少了水分的流失,延缓了营养物质可溶性固形物、胡萝卜素以及抗坏血酸含量的下降,抑制了MDA含量的增加,提高了抗氧化酶活性,同时延缓了菌落总数的增加。在贮藏15 d后,仍有商品价值和食用价值。结果表明,低温结合5%O2+10%CO2+85%N2气调包装处理可以维持鲜切胡萝卜贮藏品质并延缓采后衰老过程。     

气调包装对酱卤鸭翅品质和保鲜效果的影响

目的 研究酱卤鸭翅储藏过程中,不同气体比例气调包装对酱卤鸭翅品质和保鲜效果的影响,并确定最佳气调包装条件。方法 将酱卤鸭翅置于3种不同气体比例气调包装中,分别在13 ℃储藏1、3、5、7、10天,测量样品pH、硫代巴比妥酸（thiobarbituric acid,TBA）值、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、菌落总数和质构。结果 30%N2+70%CO2气调包装组比其他两组的pH、TBA值、TVB-N值、菌落总数均低;30%N2+70%CO2气调组和50%N2+50%CO2气调组随着储藏时间的延长酱鸭翅的嫩度和硬度均上升,而70%N2+30%CO2气调组随着储藏时间的延长酱鸭翅的嫩度和硬度呈先增高后降低的趋势。 结论 酱卤鸭翅在气调包装气体比例为30%N2+70%CO2时保鲜效果最佳。     

不同CO_2比例气调包装对冰温贮藏鲜罗非鱼片品质的影响

采用不同的气体组成A(50%CO2/10%O2/40%N2)、B(60%CO2/10%O2/30%N2)、C(70%CO2/10%O2/20%N2)和空气(对照)分别包装鲜罗非鱼片,在-0.5±0.2℃贮藏,研究不同CO2比例气调包装在冰温贮藏条件下对鲜罗非鱼片品质的影响。实验结果表明,罗非鱼的冰点在-0.8～-0.9℃之间,贮藏7d以后,与对照相比,气调包装能显著抑制产品细菌菌落总数和嗜冷菌数的增长(p<0.05)。在冰温贮藏期间,气调包装样品的肉汁渗出率要高于对照产品,随着贮藏时间的延长,四组样品的TVB-N值均有不同程度的上升,但是贮藏10d以后,对照的TVB-N值开始高于三种气调包装样品;包装方式对产品pH的影响并不明显,但是对照的pH随着贮藏时间的延长基本呈上升趋势,四种处理的罗非鱼片在整个贮藏期间TBA值几乎都没有变化。三组CO2比例气调包装样品在贮藏期间的品质差异并不明显,但是在冰温条件下,气调包装处理能明显延长鲜罗非鱼片的货架期。     

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.     

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.     

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.