凝固型香椿酸奶生产工艺的研究

以香椿和新鲜牛奶为试材,采用单因素试验及正交试验方法,研究了凝固型香椿酸奶生产的关键技术,优化了香椿的添加量及发酵条件。结果表明:凝固型香椿酸奶生产中香椿提取液添加量为5.0%,最适乳酸菌接种量为5.0%,在39℃发酵8h,所生产的酸奶表面柔滑、无气泡和乳清析出,色泽均一,酸甜适口,口感细腻,具有香椿特有香气和发酵乳香。     

极大螺旋藻酸奶加工工艺的研究

以鲜牛奶和极大螺旋藻提取液为主要原料,使用保加利亚乳杆菌和嗜热链球菌混合菌种(1:1)发酵生产极大螺旋藻酸奶.通过正交试验设计,得出极大螺旋藻酸奶的最佳配料及发酵条件为:极大螺旋藻提取液6%,白砂糖8%,酸奶稳定剂0.2%,发酵剂的接种量4%,发酵温度为43℃,发酵时间3.5h.     

无糖保健香椿酸奶的研制

无糖香椿酸奶是以香椿、鲜奶、木糖醇为主要原料制成的营养保健酸奶。本文详细介绍了无糖香椿酸奶的制作工艺，并通过L9(34)正交试验，探讨了香椿汁添加量，稳定剂用量，发酵奶用量及木糖醇添加量对酸奶质量的影响。最终表明：香椿汁添加量为15％，稳定剂用量为2．5％o，发酵奶用量为50％，木糖醇用量为8％时酸奶质量最佳。     

白灵菇酸奶加工工艺的研究

以白灵菇和鲜牛奶为主要原料,采用保加利亚乳杆菌和嗜热链球菌混合菌种发酵生产白灵菇酸奶.通过正交试验设计.得出白灵菇酸奶的最佳配方为:白灵菇汁用量(白灵菇汁:鲜牛奶,体积分数)为1:2.5、羧甲基纤维素钠(CMC)添加量为4 g/L、白砂糖添加量为80 g/L;白灵菇酸奶的最佳发酵条件为:接种量0.9 g/L、发酵时间5 h,发酵温度43℃.     

苦荞茶酸奶的研制

以苦荞茶和鲜牛奶为主要原料,以保加利亚乳杆菌和嗜热链球菌按1∶1为发酵剂,发酵温度为42℃下,对苦荞茶酸奶的加工工艺进行了研究。采用L9(34)正交试验,得出最佳试验工艺为:苦荞茶鲜牛奶比为1∶60;蔗糖添加量为7%;接种量为4%;发酵时间为3 h。以最佳工艺生产的苦荞茶酸奶色、香、味、组织状态等俱佳。     

银杏保健酸奶的研制

研究了以银杏果和鲜牛奶为原料的保健酸奶的制作。从酸乳发酵菌种的选择,食品添加物对酸奶发酵速度的影响,各种食品添加物添加量的确定,银杏酸奶配方的确定等5个方面研究了银杏酸奶的制作条件。结果表明,在银杏汁添加量为6%,低聚糖添加量为5%,稳定剂添加量为0.2%(均为质量分数),酸度为70°T时,所得产品的品质最佳。     

冬凌草酸奶的研制

以冬凌草汁和鲜牛奶为主要原料,先将冬凌草汁发酵制成发酵冬凌草汁,再与鲜牛奶混合,接种保加利亚乳杆菌和嗜热链球菌为发酵剂。采用5因素4水平正交试验,获得了制作冬凌草保健酸奶的最佳工艺参数:即发酵温度为41℃,发酵冬凌草汁体积分数为12%,蔗糖质量浓度为7g/100mL,接种发酵剂体积分数为3.5%,发酵时间为4.5h。     

发酵型菠萝酸奶生产工艺

以鲜牛奶和菠萝鲜果为主要原料,以白砂糖为调味剂,以保加利亚乳杆菌和嗜热链球菌为发酵菌种,通过测定酸度变化确定前发酵(40℃恒温)时间为2.5h,通过鲜牛奶与菠萝汁配比单因素试验确定配比量为体积比5∶1,通过接种量单因素试验确定菌种接种量为体积的3%,通过白砂糖用量单因素试验确定白砂糖用量为质量的4%,通过保加利亚乳杆菌与嗜热链球菌配比单因素试验确定菌种配比量为质量比1∶1。最后通过正交试验确定发酵型菠萝酸奶的最佳生产工艺组合为:鲜牛奶与菠萝汁按体积5∶1配比、接种量按体积3%、白砂糖用量按质量4%、发酵温度为40℃恒温发酵。并对最优产品的感官、理化和微生物指标进行了检验。     

糯玉米酸奶的研制

以糯玉米和鲜牛奶的混合液作为发酵基质,研制出糯玉米酸奶。其最佳工艺条件为:糯玉米与鲜牛奶按1∶2混合,加入10%的蔗糖,接入4%的保加利亚杆菌和嗜热链球菌(1∶1),在42℃下发酵6h可得到品质较优的糯玉米酸奶。其最佳复合稳定剂为琼脂∶黄原胶0.15%∶0.15%。     

莲藕风味酸乳饮料的研制

以新鲜莲藕汁和鲜牛奶为主要原料,采用保加利亚乳杆菌和嗜热链球菌（1∶1）发酵鲜牛奶的工艺,研制出一种风味独特兼具营养与保健作用的莲藕酸奶。通过L（934）正交试验优化了发酵工艺参数,即藕汁酶解时间为30min、蔗糖用量3%、莲藕水解液与牛奶配比为1∶5（w/w）、发酵时间10h;制成的莲藕酸奶香气浓郁,具有较高的营养和保健价值。     

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.