响应面法优化超声波辅助提取苹果籽油的工艺研究

通过预试验选取液料比、超声频率和超声时间作为Box-Behnken设计的变量,利用响应面法分析得到超声波辅助提取苹果籽油的优化工艺条件。结果表明,超声波辅助提取苹果籽油的适宜工艺参数是液料比12.6,超声频率60 kHz,超声时间35 m in,超声温度40℃,物料粉碎度为60目,在此条件下的苹果籽油提取率达到21.06%。     

苹果籽油提取工艺研究

采用溶剂浸提法和超声波辅助提取法对苹果籽油的提取进行了研究.溶剂浸提法结果表明:石油醚为提取苹果籽油的适宜溶剂,通过单因素和正交试验得出苹果籽油提取的优化工艺条件为:提取温度45℃,提取时间7h,料液比1∶6.超声波辅助提取法的结果表明:超声强化可以降低提取温度、缩短提取时间和节省溶剂用量;超声波功率和提取时间对于苹果籽油的提取均有显著的影响.试验得出,在料液比1∶6条件下,功率为250W和时间25min时提取效果最佳.     

苹果籽油的超声波辅助提取条件优化

以苹果籽为原料,以传统的索氏提取法为参照,采用超声波法辅助提取苹果籽油,研究超声功率、超声时间、超声温度、溶剂用量和物料粒度等单因素对苹果籽出油率和提取率的影响,在单因素的基础上,优化超声波辅助提取条件,并分析苹果籽油的脂肪酸组成,结果表明在粉碎粒度为50目、超声温度45℃、溶剂液料比7:1(mL:g)、超声功率为400 W、超声时间为30 min的条件下苹果籽油的出油率和提取率最高.GC-MS分析表明苹果籽油主要含不饱和脂肪酸,以亚油酸、油酸、棕榈酸为主,三者的含量总和占总脂肪酸总量的93%,索氏法和超声辅助法获得的油的成分没有明显差异.     

超声波辅助酶法提取苹果籽油工艺优化及其脂肪酸组成分析

采用超声波辅助酶法提取苹果籽油,通过单因素试验和响应面法对提取工艺进行优化,并利用气相色谱-质谱联用法测定苹果籽油的脂肪酸组成。结果表明,超声波辅助酶法提取苹果籽油的优化工艺条件为复合蛋白酶添加量1.5%(以底物质量计)、超声波频率28 kHz、超声时间20min、料液比1∶8.43、pH 7.43、酶解时间6.38 h。在优化工艺条件下,苹果籽的理论出油率达31.03%。气相色谱-质谱联用测定结果表明苹果籽油中富含不饱和脂肪酸,总含量达到89.371%,其中油酸、亚油酸含量分别为36.276%、53.095%。     

苹果籽油的超声波辅助提取及成分分析

以液料比、超声时间、超声功率3个因素对超声波辅助提取苹果籽油进行二次通用旋转优化设计试验,得到了苹果籽油提取率的回归方程,并确定最佳提取条件为:液料比8.13:1,超声时间31.3 min,超声功率165.2 W.最佳条件下苹果籽油提取率24.40%.经GC-MS分析,苹果籽油中不饱和脂肪酸含量为85.31%,其中油酸35.05%、亚油酸49.19%.     

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。     

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%。     

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。     

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.     

苹果籽油提取工艺研究

本试验采用溶剂浸提法和超声波法对苹果籽油的提取进行了研充。溶剂浸提法结果表明：石油醚为提取苹果籽油的适宜溶剂，通过单因素和正交实验得出苹果籽油提取的优化工艺条件为提取温度45℃、提取时间孙、料液比1：6。采用超声波提取结果表明：超声强化不仅可以降低提取温度、缩短提取时间和节省溶剂耗量，超声波功率和提取时间对于苹果籽油的提取均有显著的影响。试验得出，在料液比1：6条件下，以功率250w和时间25min时提取效果最佳。     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.