乳酸及乳酸钠的鲜肉保鲜中的应用

本试验采用乳酸、乳酸钠及其二者的混合物按不同比例加入鲜猪肉中，在室温３０摄氏度湿度８５－９５％条件下贮存，定时进行肉的鲜度检测，并与未添加任何添加剂的肉作比较，试验结果表明，单一使用与混合使用这二种添加剂均有不同程度的保鲜效果，以０．２１％乳酸、２．７９％乳酸钠添加量保鲜效果较好，可延长保鲜期１－３天。     

复合防腐剂在常熟叫化鸡加工中的应用

研究了Nisin、山梨酸钾、乳酸钠复合防腐剂对常熟叫化鸡的保鲜效果。通过单因子试验和正交试验,对叫化鸡在不同贮存期作感官评定及菌落总数测定,研究复合防腐剂的保鲜作用。结果表明,乳酸链球菌素、山梨酸钾、乳酸钠添加量分别为0.02%、0.2%、4%时,防腐效果较好。     

乳酸钠对冷鲜肉保鲜效果的影响

目的:主要研究乳酸钠及乳酸钠与乳酸链球菌素复配液用于冷鲜肉的保鲜。方法:配制0%、1%、2%、3%、4%、5%5个不同乳酸钠浓度的保鲜液,用浸泡的方法对肉进行处理,无菌包装,冷藏,通过测定4个指标(细菌总数、p H值、挥发性盐基氮、感官指标)找出最有效的保鲜浓度;利用全面试验,以细菌总数为检测指标,研究乳酸钠和乳酸链球菌素复配液对冷鲜肉的保鲜效果。结果:乳酸钠有效保鲜浓度为3%,最佳的复配浓度是乳酸钠10 g/kg、乳酸链球菌素(nisin)0.3 g/kg。结论:一定浓度下,乳酸钠能有效对冷鲜肉进行保鲜,与乳酸链球菌素复配能提高保鲜效果。     

低温禽肉制品非冷藏保鲜液配方的研究

以溶菌酶、Nisin（乳链菌肽）、乳酸钠和双乙酸钠为保鲜剂应用于低温禽肉制品保鲜，采用正交试验方法，对配比成分的比例进行优选。结果表明0．05％Nisin＋0.05％溶菌酶＋2％乳酸钠＋1％双乙酸钠的保鲜液配方较优，用此保鲜液处理再结合真空包装能使低温禽肉制品在15℃～20℃条件下保鲜20d。     

复配防腐剂在熏煮香肠中的应用

实验以熏煮香肠为研究对象,以处理前后香肠中挥发性盐基氮(TVB-N)含量和菌落总数的变化作为评价指标,研究单一防腐剂乳酸钠、双乙酸钠、乳酸链球菌素的防腐保鲜作用,并通过筛选不同防腐剂复配比例优化防腐效果。结果显示,当双乙酸钠添加量0.04%、乳酸钠2.0%、乳酸链球菌素0.006%时,防腐效果最佳。     

酱鸭保鲜技术的研究

利用乳酸钠和乳酸链球菌素在肉制品保鲜中的协同作用,将乳酸钠和乳酸链球菌素结合真空包装、低温杀菌技术应用于酱鸭保鲜。实验结果表明,乳酸钠和乳酸链球菌素对酱鸭均具有明显的保鲜效果,且以乳酸钠30g／kg和乳酸链球菌素0.20g/kg为最佳配比,可使酱鸭在常温(20~25℃)下,保质期达到30d。     

响应面法优化山药鱼肉饼的生物抑菌保鲜剂配方

研究了生物保鲜剂对山药鱼肉饼的抑菌效果。在单因素试验的基础上,采用响应面法分析了壳聚糖、乳酸钠、乳酸链球菌素对山药鱼肉饼抑菌保鲜作用的影响,建立了二次回归方程,得到复合生物抑菌保鲜剂的最优配方为:壳聚糖0.35%、乳酸钠4.0%、乳酸链球菌素250 mg/kg,添加此配方保鲜剂的山药鱼饼冷藏10 d测得细菌生长对数值为2.56。     

基于神经网络法优化即食皱纹盘鲍栅栏模式

以栅栏技术理论为指导,采用神经网络模型优化不同栅栏模式对即食鲍鱼（Haliotis discus hannai Ino）产品的防腐保鲜效果。通过研究几个栅栏因子（烘干后产品的水分活度（aw）、乳酸链球菌素（Nisin）、乳酸钠的添加量以及杀菌温度）组合得到的不同栅栏模式的防腐保鲜效果以及对产品品质的影响,以菌落总数及感官评分作为响应值建立神经网络模型并进行优化。结果表明：产品最适栅栏模式为：aw为0.92,Nisin、乳酸钠添加量分别为0.39 g/kg、1.6%,杀菌温度89 ℃,此栅栏模式防腐保鲜效果好,且能较好地保持产品的质地和风味。     

乳酸链球菌素应用于延长软雪糕奶浆保质期的研究

通过对乳酸链球菌素(Nisin)、溶菌酶、苯甲酸钠、乳酸钠4种防腐剂、保鲜剂对软雪糕奶浆的保鲜效果研究,确认软雪糕奶浆中添加50～100mg/kgNisin可达到在4℃的环境中保鲜12d以上,有效地延长了软雪糕奶浆的保质期,并且保持了软雪糕奶浆的风味。     

乳酸、乳酸钠与Nisin复合对冷却羊肉的保鲜效果

用乳酸、乳酸钠与Nisin复合保鲜剂对冷却羊肉进行处理,自封袋包装后在4±1℃的环境中贮藏,测其在贮藏期间的菌落总数、挥发性盐基氮、p H和感官评分,用权重对不同配比的保鲜液对冷却羊肉的保鲜效果进行综合评估,并在此基础上进行优化。结果表明:乳酸浓度0.15%、乳酸钠浓度0.3%、乳酸链球菌素浓度为0.05%时保鲜效果最佳,该处理下的样品在贮藏20 d时各项品质指标仍能保持在鲜肉范围内。     

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.