响应面法优化微波提取阳荷水溶性膳食纤维工艺

研究野生阳荷水溶性膳食纤维的最佳提取工艺,以提取时间、料液比、微波功率和浸提液pH值为影响因素,进行四因素三水平的响应面试验设计,对其提取工艺条件进行优化,结果表明：最佳提取工艺条件为提取时间151.4 s、料液比1∶33（g/mL）、微波功率264 W、浸提液pH 3.65,此条件下水溶性膳食纤维的提取率为5.52%,与理论值5.75%相差较小。由此可知,响应面法优化微波辅助提取阳荷水溶性膳食纤维具有时间短、能耗低、提取率高等特点。     

微波提取花生茎中水溶性膳食纤维的工艺优化

以花生茎为原料,微波提取花生茎中水溶性膳食纤维。通过对浸泡时间、微波时间、微波功率、微波温度和料液比等影响因素进行单因素及正交试验,获得花生茎水溶性膳食纤维的最佳提取工艺条件：浸泡时间55min、微波时间4min、微波功率800W、微波温度90℃、料液比1:14(g/mL),水溶性膳食纤维提取率达到6.0%,NSP 含量为94.68%,SDF 综合评分为65.12%。     

微波辅助提取芹菜渣水溶性膳食纤维工艺条件研究

以芹菜榨汁后的芹菜渣为原料,采用微波法提取芹菜渣水溶性膳食纤维。研究了浸泡时间、微波时间、微波功率和料液比等对水溶性膳食纤维得率的影响,在单因素试验基础上,通过L9(34)正交试验确定提取芹菜渣水溶性膳食纤维的最佳工艺条件为:浸泡时间50 min,微波时间3 min,微波功率600 W,料液比1∶30(g/m L)。此条件下,芹菜渣水溶性膳食纤维的得率达到13.13%。试验得到的芹菜膳食纤维,颜色为淡黄色,无任何特殊气味,是较为理想的水溶性膳食纤维。该方法提取芹菜渣中的水溶性膳食纤维具有便捷、高效、节能的特点。     

超声波-微波协同提取沙棘果皮渣中可溶性膳食纤维工艺优化

采用超声波-微波协同法提取沙棘果皮渣中可溶性膳食纤维的工艺条件。通过单因素实验研究柠檬酸质量分数、料液比、微波功率、提取时间对沙棘果皮渣中可溶性膳食纤维提取得率的影响,进一步用Box-Behnken法优化沙棘果皮渣中可溶性膳食纤维最佳提取工艺。结果表明,在柠檬酸质量分数为3%,料液比1:16 g/mL,微波功率620 W,提取时间60 min的条件下,沙棘果皮渣中可溶性膳食纤维提取效果最佳,提取得率为11.07%±0.26%,与模型预测值10.83%误差为2.22%。制备的沙棘果皮渣可溶性膳食纤维持水力为8.02 g/g,持油力为4.19 g/g,膨胀力为3.82 mL/g。超声波-微波协同法是一种提取沙棘果皮渣中可溶性膳食纤维的有效方法。     

荞麦皮粉中膳食纤维的制备工艺研究

以荞麦皮粉为原料,采用碱法提取膳食纤维,通过单因素及正交试验得出最佳提取工艺条件,并对所得膳食纤维进行性质测定。结果表明,最佳提取工艺条件为:碱解温度80℃,氢氧化钠质量分数1.0%,料液比1:16(g/mL),碱解时间80min。在此条件下膳食纤维得率为20.39%,水不溶性膳食纤维持水力为5.97 g/g,膨胀力为7.4 mL/g,水溶性膳食纤维溶解率为96%。     

微波提取香蕉茎干中水溶性膳食纤维的工艺研究

探讨了以香蕉茎干为原料,用微波提取水溶性膳食纤维的工艺及其操作条件,并与直接水提法进行比较。结果表明,微波法最佳工艺条件为提取时间2min、提取功率900W、液料比为2ml/g、pH4,此条件下SDF 干基产率达到9.86%。微波法工艺明显优于直接水提法。     

超声波辅助提取花生壳水溶性膳食纤维工艺研究

以花生壳为原料,采用超声波辅助法提取水溶性膳食纤维,在单因素试验基础上,通过正交试验确定提取花生壳水溶性膳食纤维最优工艺。结果表明,提取花生壳水溶性膳食纤维最优工艺条件为:提取温度80℃、提取时间20 min、料液比1:15(g/mL)、超声波功率320 W;在此工艺条件下,花生壳水溶性膳食纤维提取率为18.54%;所得水溶性膳食纤维膨胀力为6.73 ml/g、持水力为7.21 g/g,成品呈黄褐色,气味良好。     

响应面优化苣荬菜中水溶性膳食纤维提取及其理化性质

为优化超声波法提取苣荬菜中的水溶性膳食纤维工艺,考察提取液pH、料液比、超声功率、提取时间和温度等单因素对水溶性膳食纤维素得率的影响,并通过三因素三水平Box-Benhnken试验设计及响应面分析优化工艺参数。结果表明,最佳提取条件为:pH 3,料液比1:25 g/mL,超声波功率320 W,超声时间22 min,提取温度70℃。在此条件下苣荬菜中水溶性膳食纤维的得率为3.65%±0.02%。水溶性膳食纤维的持水力为465%,溶胀力为5.53mL/g。     

雪莲果中SDF的提取工艺及特性研究

以雪莲果为材料,采用单因素试验和正交试验对热水浴法制备水溶性膳食纤维的工艺进行优化设计。影响雪莲果中水溶性膳食纤维提取的得率主要因素有:酸的种类、料液比、反应液的pH、提取时间、提取温度。实验表明,雪莲果水溶性膳食纤维的最佳提取工艺条件:盐酸浸提、料液比1∶5(g/g)、pH为6.0、提取时间120 min、温度80℃,此条件下雪莲果水溶性膳食纤维的提取率可达到5.43%。各因素的影响次序为:料液比提取温度反应时间pH。雪莲果水溶性膳食纤维的持水力、膨胀力、结合水力分别为2.676 g/g、1.904 mL/g、1.545 g/g,对不饱和脂肪酸的吸附力为1.370 g/g。     

微波辅助提取金针菇、香菇菇柄中氨基酸的研究

为充分利用金针菇、香菇加工、食用过程中产生的副产物,以金针菇、香菇菇柄为原料,通过微波辅助提取其中的游离氨基酸。研究了微波功率、料液比、微波时间等单因素对提取游离氨基酸的影响,通过正交试验研究了微波辅助提取的最佳条件。结果表明,影响金针菇菇柄游离氨基酸提取的各因素的主次顺序为微波功率料液比处理时间,最佳提取条件为微波功率150 W、料液比1︰20(g/m L)、微波时间3 min,在此条件下金针菇菇柄中游离氨基氮提取率为8.38 mg/g。影响香菇菇柄游离氨基酸提取的各因素的主次顺序为微波功率料液比处理时间。最佳提取条件为微波功率150 W、料液比1︰40(g/m L)、微波时间3 min,在此条件下香菇菇柄中游离氨基氮提取率为4.60 mg/g。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.