乌龙茶酸奶的工艺研究

以乌龙茶和酸奶为主要原料,对乌龙茶汁的提取方法以及乌龙茶酸奶发酵工艺进行研究。对茶汁提取时间、提取温度、料液比和乌龙茶酸奶的菌种接种量、蔗糖添加量、稳定剂添加量、茶汁添加量酸奶的影响因素进行研究,利用单因素试验和正交试验,确定最佳的制作工艺配方。研究结果表明:乌龙茶汁提取条件是温度90℃、时间5min、茶和水的料液比为1:30,牛奶中添加乌龙茶汁量为5%,蔗糖6%,稳定剂添加量0.05%,菌种接种量2%,42℃发酵24h。制作出的乌龙茶带着乌龙茶特有的清香,口感顺滑。     

不同茶类酸奶的研制

目的研制茶味酸奶,增加酸奶产品的多样性。方法采用6大茶类为原料,利用响应面优化方法确定茶叶酸奶的最佳配方。结果普洱茶、红茶、白茶、黄茶、绿茶、乌龙茶制作的茶叶酸奶最佳配方为:浸提茶汤茶水比为1:10,浸提温度为90℃,浸提时长为20min;牛奶中茶汤添加量5%,白砂糖添加量8%,菌种接种量2%,发酵时间6 h,发酵温度为42℃时制作的茶叶酸奶品质具佳。结论鲜牛奶中添加5%茶汤,在42℃下发酵6 h制作的茶叶酸奶奶香浓郁,与牛奶融合较好,具有独特口感与茶香,比普通酸奶滋味醇厚。     

马铃薯面包加工工艺研究

以高筋小麦粉和马铃薯全粉为主要原料制作面包。通过单因素实验和正交试验筛选马铃薯面包的最佳加工工艺,最终确定马铃薯面包的最佳配方为:马铃薯全粉添加量7.5%,盐添加量0.5%,酵母添加量1.6%,糖添加量10%;最佳工艺为:发酵时间100 min,焙烤温度面火180℃、底火160℃,焙烤时间10 min。在此条件下制作的马铃薯面包口感松软,内部气孔均匀,具有马铃薯的特殊香味。     

糯米酒制作凝固型酸奶的工艺研究

试验利用糯米酒制作凝固型酸奶,米酒发酵液的最适灭菌条件为95℃、5min,原料奶总固体物最佳含量16%.对蔗糖添加量、米酒发酵液添加量、发酵温度、发酵时间和发酵剂添加量做单因素试验,以米酒酸奶的感官评价为指标,通过正交试验,得出凝固型米酒酸奶最佳工艺组合蔗糖添加量7%、米酒发酵液添加量18%、发酵剂添加量1%、发酵温度42℃、发酵时间4h.其中米酒发酵液添加量对米酒酸奶品质影响显著.     

棕榈油基绿豆糕的制备工艺研究

传统绿豆糕的制作多采用大豆油或以大豆油为基础油的调和油,为提高产品的货架期、经济价值和营养价值,选用5℃棕榈油、24℃棕榈油和45℃棕榈油分别部分替代大豆油制作绿豆糕,以棕榈油添加量、复配油脂添加量和复配油脂加热时间为试验因素,以产品的感官评分和硬度为参考指标进行优化试验。结果表明:5℃棕榈油基绿豆糕,棕榈油添加量为80%、复配油脂添加量为20%、复配油脂加热时间为3.5 min;24℃棕榈油基绿豆糕,棕榈油添加量为80%、复配油脂添加量为23%、复配油脂加热时间为3.0 min;45℃棕榈油基绿豆糕,棕榈油添加量为60%、复配油脂添加量为12%、复配油脂加热时间为4.5 min。按上述工艺制作的绿豆糕,其感官评分和硬度与传统绿豆糕相近。     

麻球实验室制作工艺及配方优化

以麻球品质评分为考核指标,采用单因素和正交试验的方法,对麻球制作工艺参数中的初始油温、油炸温度、油炸时间、饧面时间,以及配方中加水量、加糖量、小麦粉添加量、熟粉团比例等因素进行研究。结果表明:影响麻球品质评分的工艺参数主次顺序为油炸温度油炸时间初始油温饧面时间,最佳制作工艺条件为饧面时间3h,初始油温100℃,油炸温度120℃,油炸时间20min。影响麻球品质评分的配方主次顺序为加水量加糖量熟粉团比例小麦粉添加量,最佳制作配方为加水量90%,加糖量15%,小麦粉添加量5%,熟粉团比例10%。     

红枣山楂桂圆酸奶的研制

结合红枣、桂圆、山楂和牛奶的有益作用,研制出集营养与保健功能于一体的红枣山楂桂圆酸奶。以牛奶、红枣、桂圆、山楂为原料,以乳酸菌为发酵剂,通过单因素和正交试验确定红枣山楂桂圆发酵乳的制作工艺。试验表明,果汁最佳添加量为15%,蔗糖添加量为7%,接种量为11%,发酵温度45 ℃,发酵时间为5 h,4 ℃后熟12 h。利用此工艺制备的酸奶风味独特,营养丰富,感官评分为95.6分。     

利用蜂蜡制备菜籽油基凝胶油的研究

以菜籽油为基料油,添加一定量的蜂蜡,采用加热搅拌和冷却的方法制备菜籽油基凝胶油,研究蜂蜡添加量、加热时间、加热温度、冷却时间对凝胶油硬度及漏油率的影响。结果表明:当蜂蜡添加量为6%～10%时,随着蜂蜡添加量的增加,漏油率呈下降趋势,硬度呈上升趋势。不同蜂蜡添加量组90℃时漏油率均最低,硬度最为适中。此外,除6%蜂蜡添加量组外,不同蜂蜡添加量组在加热时间30 min、冷却时间24 h时的硬度均为最大,漏油率均为最低。进一步用在蜂蜡添加量10%、加热温度90℃、加热时间30 min、冷却时间24 h条件下制备的凝胶油制作饼干,发现与相同配方下制作的黄油饼干相比,其硬度和脆性均略大。     

豆渣饼干的研制

以大豆渣和低筋面粉为主要原料研制含有豆渣的饼干。通过单因素试验和正交试验确定豆渣饼干的最佳配方参数。结果表明:制作豆渣饼干的最佳配方是豆渣粉∶低筋面粉质量比20∶80、泡打粉添加量1.8%、绵白糖添加量30%、全脂奶粉添加量5%、花生油添加量12%,最佳烘烤温度是180℃、烘烤时间为6 min。按照此法制作的豆渣饼干口感松脆,色泽金黄,有较好的豆香味。     

茯苓糙米黑豆保健馒头研制

通过单因素试验及正交试验研究了茯苓、糙米、黑豆保健馒头的最佳工艺,试验结果表明,茯苓、糙米、黑豆与小麦粉混合的最佳配比是茯苓粉添加量12%、糙米粉添加量15%、黑豆粉添加量10%。馒头制作的最佳工艺条件为加水量50%(以混合粉重量计)、酵母量1%(以混合粉重量计)、发酵温度38℃、湿度88%、发酵时间40 min,成型后在发酵温度38℃、湿度88%下再次醒发15 min,蒸汽蒸制20 min,取出冷却到室温。此条件下生产的馒头具有较好的品质和较高的营养价值。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.