甘蓝泡菜发酵菌种的复配研究

研究了用于蔬菜发酵的3种天然优势乳酸菌菌株——短乳杆菌、干酪乳杆菌、植物乳杆菌单独或复配使用对发酵甘蓝品质的影响。甘蓝接种后,常温条件(约23℃)下发酵3d,监测pH值、总酸、亚硝酸含量、乳酸菌总数的变化情况及感官品质。结果表明短乳杆菌与植物乳杆菌按1∶1复配,总接种量为2%～3%,泡菜的发酵效果最好。当总接种量为2%时,发酵后泡菜的pH为3.35,总酸为0.74%,乳酸菌活菌数为8.93×10~7cfu/mL,感官品质最佳,评分值达到12.1/15,亚硝酸盐含量为14.2mg/kg。     

海芦笋腌渍工艺条件优化

以海芦笋为原料,探讨其在腌渍过程中,亚硝酸盐含量的变化。研究内容包括不同浓度的食盐、不同维生素C加入量及添加时间、接种乳酸菌对腌渍产品中亚硝酸盐含量的影响,以确定腌渍海芦笋的优化工艺及配方。从而能更好控制腌制过程中出现不利因素,为绿色腌渍提供更好的方法。结论:1.腌渍食盐浓度越低亚硝酸盐起始值就越小,峰值出现早,峰值小;浓度越高,峰值出现晚,峰值高。实验得出10%食盐腌渍效果较好。2.在腌渍中后期加入维生素C和初期加入维生素C相比,前者能更好地控制亚硝酸盐浓度。3.接种乳酸菌腌渍比常规腌渍能更好抑制亚硝酸盐的生成,其中植物乳杆菌的抑制效果比较明显。     

植物乳杆菌对黄秋葵泡菜亚硝酸盐含量的影响及其发酵工艺研究

该研究以新鲜黄秋葵为主要原料,探讨植物乳杆菌（Lactobacillus plantarum）发酵对黄秋葵泡菜亚硝酸盐含量的影响,并以亚硝酸盐含量为考察指标,通过单因素试验及响应面试验对其发酵工艺参数进行优化。结果表明,与自然发酵相比,植物乳杆菌发酵制作的黄秋葵泡菜的亚硝酸盐含量（最高达9.78 mg/kg）更低,成熟期更短;植物乳杆菌发酵黄秋葵泡菜的最优发酵工艺为接种量3.5%,发酵温度30 ℃,发酵时间5.5 d,食盐水浓度4.0%,在此优化工艺条件下,黄秋葵泡菜中的亚硝酸盐含量最低,为（2.98±0.02） mg/kg,低于国家腌渍蔬菜亚硝酸盐的限量标准（≤20 mg/kg）,比优化前降低1.21 mg/kg。     

人工接种乳酸菌对泡菜感官品质和亚硝酸盐含量的影响

研究了不同的乳酸菌菌种、添加比例、添加量和加糖量对泡菜pH和亚硝酸盐含量的动态变化。通过单因素研究和优化实验,确定了乳酸菌菌种、添加比例、添加总量和加糖量。结果表明,植物乳杆菌和干酪乳杆菌混合发酵泡菜,添加比例为2∶1时,泡菜的发酵时间明显缩短,泡菜的色、香、味较好,亚硝酸盐含量显著降低。     

不同乳酸菌发酵萝卜干的品质动态变化研究

为了缩短生产周期,提高产品质量和安全性,本文以萝卜干为原料,分别接种肠膜明串珠菌、玉米乳杆菌、副干酪乳杆菌和乳酸乳球菌,以自然发酵为对照,研究不同乳酸菌对萝卜干品质的影响。结果表明,接种发酵和自然发酵p H随发酵时间先降低后保持稳定;亚硝酸盐含量随发酵时间先增加后减小,55 d时接种发酵亚硝酸盐含量明显小于自然发酵(p0.05),肠膜明串珠菌和玉米乳杆菌发酵亚硝酸盐峰值出现的时间比副干酪乳杆菌、乳酸乳球菌和自然发酵早22 d左右;接种发酵和自然发酵的总酸度、挥发酸、挥发酯和游离氨基酸随发酵时间呈上升趋势。乳酸菌纯种发酵萝卜干,可以加快发酵速度,降低亚硝酸盐含量,改善产品品质,其中肠膜明串菌表现最佳。     

不同益生菌发酵剂对复合果蔬汁品质的影响

以沙棘、胡萝卜和黑枣为原料制备复合果蔬汁,分别接种植物乳杆菌、鼠李糖乳杆菌及其组合（1∶1,体积比）进行发酵,比较复合果蔬汁发酵过程中乳酸菌总数、pH值、总酸、可溶性蛋白、还原糖、有机酸、总黄酮、总多酚和体外抗氧化活性等指标的变化。结果表明,植物乳杆菌、鼠李糖乳杆菌及其组合发酵复合果蔬汁中还原糖含量无显著差异。相比直接接种植物乳杆菌或鼠李糖乳杆菌单一菌种发酵复合果蔬汁,植物乳杆菌和鼠李糖乳杆菌耦合发酵可显著增加乳酸菌的菌落总数（P<0.05）,提高总酸、总黄酮、总多酚、乙酸和乳酸等物质的含量（P<0.05）,增加体外抗氧化活性（P<0.05）。     

乳酸菌降低发酵烤肠中亚硝酸盐残留量的研究

本实验针对乳酸菌降低发酵烤肠亚硝酸盐残留量进行了研究,以发酵烤肠的亚硝酸盐的残留量、pH值为指标,并兼顾产品的品质。针对影响发酵烤肠的四个主要因素：发酵菌种(植物乳杆菌、嗜热乳链球菌:保加利亚乳杆菌=1:1混合菌、德国科汉森乳酸菌)、接种量、发酵温度和发酵时间进行了单因素试验;在确定较优工艺参数的基础上,以产品的亚硝酸盐残留量的降解率和感官评分为指标,进行了正交试验,最终确定最优化的工艺参数为：发酵菌种是德国科汉森复合乳酸菌,接种量为2.0%,发酵温度为30℃,发酵时间为22h。     

乳酸菌对低盐腌制榨菜理化性质及风味成分的影响

为了获得一种更为安全健康的榨菜腌制方法,以乳酸菌（植物乳杆菌）为发酵剂在低盐条件下接种腌制榨菜。对一次接种、分次接种低盐腌制榨菜以及传统高盐腌制榨菜腌制过程中的pH值、乳酸菌数、亚硝酸盐含量,以及最终榨菜产品的氨基态氮含量以及风味物质成分进行了测定。分次接种和一次接种相对于对照组,在初腌阶段,可以迅速降低pH到4以下,增加乳酸菌数达到108 cfu/mL,促使亚硝酸盐峰值提前4~6 d出现,亚硝酸盐峰值仅为1 μg/mL;而复腌时分次接种可以维持腌制后期卤水pH为3.6~3.8,,乳酸菌数保持稳定,并能再次降低亚硝酸盐峰值低于0.3 μg/mL。氨基态氮含量的测定结果也表明接种乳酸菌腌制榨菜多于对照组;GC-MS测定风味物质,接种榨菜风味成分优于对照组,而分次接种腌制榨菜更优于一次接种腌制榨菜。     

几株应用于发酵肉制品的乳酸菌的筛选

为了筛选出符合发酵肉制品优质乳酸菌发酵剂,对不同乳酸菌发酵性能进行研究,通过实验筛选出耐盐、耐亚硝酸盐、不分解蛋白质和脂肪、适于肉类发酵的优质乳酸菌。试验表明,植物乳杆菌、发酵乳杆菌和乳酸乳球菌三株乳酸菌均能在6%食盐溶液和1.5×10-4亚硝酸盐溶液下能够很好生长,因而这三种乳酸菌可耐受食盐和亚硝酸盐,并且均不分解蛋白质和脂肪。得出结论,植物乳杆菌、发酵乳杆菌、干酪乳杆菌和德氏乳杆菌均为适宜于使用在发酵肉制品中的发酵剂。     

接种乳酸菌对大白菜腌渍发酵的影响

以接种乳酸菌和自然发酵进行大白菜腌渍,测定发酵过程酸,pH,亚硝酸盐,硝酸盐及成品中Vc含量,结果表明,接种发酵使腌渍过程酸快速积累,pH值迅速下降,亚硝酸盐生成曲线平缓,峰值低,成品中亚硝酸盐含量低,硝酸盐分解被控制,成品中硝酸盐含量高,成品在Vc含量高。     

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.     

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.