微波辅助提取辣木籽油的工艺优化研究

以辣木籽为原料,采用微波辅助法提取辣木籽油,研究液料比、微波时间、微波功率对辣木籽油提取率的影响。通过响应面分析方法得出优化的微波辅助提取辣木籽油的工艺条件:以石油醚(30~60℃)为提取溶剂、液料比9∶1(m L/g)、微波时间7 min、微波功率455 W,在此条件下辣木籽油的提取率为96.78%。通过GC法对提取的辣木籽油进行脂肪酸组成分析,与传统方法相比,脂肪酸组成无明显差异。     

超声波辅助溶剂萃取辣木籽油条件优化

用超声波辅助溶剂萃取辣木籽油,以出油率为评价标准,优化萃取过程的最佳工艺条件.通过4个因素的单因素试验、正交试验以及验证试验,优化出了影响辣木籽出油率的主要因素水平和最佳工艺条件.结果显示,超声波辅助溶剂萃取辣木籽油的最佳条件为:溶剂石油醚,提取次数2次,提取时间40 min,超声波频率28 kHz,液料比8:1(V/W),在此条件下,辣木籽的平均出油率为35.85%,提取率96%,表明超声波辅助溶剂萃取法是一种可用于萃取辣木籽油的适宜方法.     

响应面法优化微波辅助提取海蓬子籽油工艺

以成熟海蓬子种子为原料、石油醚为提取溶剂,采用微波辅助法提取海蓬子籽油。在微波温度、微波时间、料液比和微波功率对海蓬子籽油得率影响4 个单因素试验的基础上,通过响应面法优化微波辅助提取海蓬子籽油的最佳工艺条件。结果表明,微波辅助提取海蓬子籽油的最佳工艺条件为：微波温度55 ℃、微波时间5 min、料液比1∶10（g/mL）、微波功率700 W。在此条件下,海蓬子籽油得率为32.58%。与传统索氏抽提法相比,微波辅助提取海蓬子籽油的得率提高了0.15%,而提取时间仅为索氏抽提法的1.39%。     

正交试验法优化微波辅助提取树莓籽油工艺

以干燥的树莓籽为原料,正己烷为提取有机溶剂,优化微波辅助提取树莓籽油的最佳工艺。在微波温度、料液比、微波时间和微波功率4个单因素实验的基础上,采用正交试验法优化微波辅助提取树莓籽油的最佳工艺条件。实验结果表明,在所考察的各个因素中,微波功率对树莓籽油的提取得率影响最大,其次是微波时间和微波温度,料液比对树莓籽油的得率影响最小。微波辅助提取树莓籽油的最佳提取工艺条件为A2B3C3D1,即浸提树莓籽油宜选用的条件为微波温度55℃,微波时间9min,料液比1∶16(g/m L),微波功率400W。在此最佳提取条件下,微波辅助提取树莓籽油得率为16.52%。     

响应面法优化超声波辅助提取黄秋葵籽油工艺研究

以正己烷为提取溶剂,采用超声波辅助提取黄秋葵籽油。在单因素试验的基础上,以黄秋葵籽油得率为响应值,利用响应面法优化超声波辅助提取工艺条件。结果表明:黄秋葵籽油的最佳工艺条件为物料粒度80目、料液比1∶8、超声功率120 W、提取时间45 min、提取温度60℃、提取次数2次;对优化的工艺条件进行验证,黄秋葵籽油的得率为17.27%,与预测值接近。     

微波辅助提取罗勒籽油的响应面法优化

采用微波辅助提取法从罗勒籽中分离罗勒籽油.在单因素实验设计和分析的基础上,通过响应面法对微波辅助提取罗勒籽油的最佳工艺条件进行优化;此外,就三种不同方法对罗勒籽油得率的影响进行了研究.结果表明:微波辅助提取罗勒籽油的最佳工艺条件为:微波时间3 min,料液比1∶13(g/mL),微波功率600W,微波温度60℃,在此条件下罗勒籽油得率为18.53％.与索氏提取法和有机溶剂回流提取法相比,微波辅助法提取罗勒籽油得率最高,并具有时间最短、效率最高等优点.     

超声波辅助与溶剂萃取番木瓜籽油的比较研究

以番木瓜籽为原料,对2种提取番木瓜籽油的工艺和效果进行比较。通过正交试验得到溶剂法提取番木瓜籽油的最佳工艺条件为:溶剂选用石油醚,料液比1∶8(g∶m L),提取时间2 h,提取温度80℃,番木瓜籽油提取率为35.8%;超声波辅助法提取番木瓜籽油的最佳工艺条件为:溶剂选用石油醚,料液比1∶4(g∶m L),超声温度50℃,超声时间20 min,超声功率120 W,番木瓜籽油提取率为38.8%。结果表明,超声波辅助法提取的番木瓜籽油得率比溶剂法高,并且超声波辅助法比溶剂法提取的时间短、温度低,是一种短时高效的提取方法。     

超声波辅助提取辣木油的工艺研究

本实验通过超声波辅助提取辣木油的正交试验,研究了影响辣木油提取的主要因素,以及辣木油超声波辅助提取的最佳萃取工艺。结果表明,在提取次数2 次、提取时间40min、超声波频率28kHz、液料比8:1(V/m)的条件下,辣木油平均得率为35.85%(占辣木种子含油率的96%)。     

超声波辅助溶剂浸出法提取巴塘核桃油工艺优化及脂肪酸组分分析

研究超声波辅助溶剂浸出法提取巴塘核桃油的最佳工艺及其脂肪酸组分。通过单因素以及L₉(33)正交实验研究料液比、单次超声时间与间歇时间比及超声时间3个因素对提油率的影响,得到最佳提取条件;采用气相色谱(GC)法测定脂肪酸组分,并与超声波辅助水酶法提取核桃油的脂肪酸组分进行对比分析。结果表明:超声波辅助溶剂浸出法提取该油的最佳工艺条件为:料液比为1:7.5 g/mL,单次超声时间与间歇时间比为3:8 s/s,超声时间为10 min,该条件下提油率达到58.90%;超声波辅助溶剂浸出法与超声波辅助水酶法提取的核桃油脂肪酸主要组分均为亚油酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚麻酸,且相对含量差异不显著(p>0.05)。结论:超声波辅助溶剂浸出法操作简单、快速、得率高,提取出的核桃油营养丰富、品质优良,为工业化应用提供了精确有效的参考标准,为广泛开发利用巴塘核桃油资源提供了良好的参考价值。     

石榴籽油提取工艺的研究

以石榴籽为原料,利用超声波辅助有机溶剂提取石榴籽油,在单因素试验的基础上,通过正交试验研究了料液比、提取时间、提取温度、超声波功率对石榴籽油得率的影响,确定了超声波辅助提取石榴籽油的最佳工艺条件。结果表明,石榴籽油的最佳提取工艺条件为:料液比1∶20,提取时间40 min,提取温度50℃,超声波功率400 W。在该条件下石榴籽油得率为21.77%。     

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.