响应面优化水酶法提取奇亚籽油工艺

以奇亚籽为原料,采用水酶法提取奇亚籽油。在单因素实验的基础上,采用响应面法对水酶法提取奇亚籽油的工艺条件进行优化。结果表明,水酶法提取奇亚籽油的最佳工艺条件为:碱性蛋白酶作为酶解用酶,酶解温度45℃,液料比8. 47∶1,pH 10,酶添加量5. 17%,酶解时间2. 16 h。在最佳条件下,奇亚籽油提取率为89. 53%。     

超声波—表面活性剂协同辅助提取江永香柚籽多糖工艺的优化

以江永香柚籽为原料,通过单因素试验研究超声时间、表面活性剂、提取温度、提取时间、料液比和搅拌转速对江永香柚籽多糖提取率的影响,在该基础上对提取温度、提取时间和料液比进行响应面优化。结果表明,江永香柚籽多糖的最适提取工艺为:超声时间4 min,SLS表面活性剂用量1.5%,提取温度71℃,提取时间50 min,料液比120(g/m L),搅拌转速150 r/min,该条件下江永香柚籽多糖平均提取率为4.69%。     

二次正交旋转组合设计优化水酶法提取牡丹籽油工艺

以牡丹籽为原料,采用水酶法提取牡丹籽油。通过单因素试验,研究酶解温度、酶解时间、酶添加量、液料比对牡丹籽油提取率的影响,在此基础上,采用二次正交旋转组合试验对提取工艺条件进行优化。结果表明,各因素对牡丹籽油提取率的影响强弱顺序依次为酶解温度、液料比、酶添加量、酶解时间,水酶法提取牡丹籽油的最优工艺条件为:酶解温度52℃、液料比3∶1、酶添加量3.6%(以牡丹籽质量计)、酶解时间4 h,在此条件下牡丹籽油提取率可达92.8%。     

水酶法提取石榴籽油工艺研究

以石榴籽为原料,利用水酶法提取石榴籽油.通过单因素及二次回归旋转组合实验研究了料液比、石榴籽粒度、酶的种类、酶解温度、提取时间、离心时间、pH以及酶的添加量等因素对出油率的影响,确定了水酶法提取石榴籽油的最佳工艺条件.结果表明,酶解最佳工艺参数为:用Alcalase蛋白酶添加量为1.0%(mL/g),原料粒度40目,料液比1:5(g/mL),提取温度50℃,提取时间6h,pH8.0,离心时间25min,在该工艺条件下石榴籽油出油率达18.2%.     

二次正交旋转组合设计优化水酶法提取猕猴桃籽油的工艺

以猕猴桃籽为原料,采用水酶法提取猕猴桃籽油。在单因素试验的基础上,采用二次正交旋转组合试验对猕猴桃籽油的提取工艺进行优化,建立了各主要影响因素与猕猴桃籽出油率之间的回归模型。试验结果表明:各因素对猕猴桃籽出油率影响的顺序为液料比>酶解pH>酶添加量>酶解温度,水酶法提取猕猴桃籽油的最优工艺参数为液料比10,酶解温度50℃,酶添加量2.5%,酶解pH 9.0。在此条件下,提取二次总出油率为27.17%,萃取率达86.75%。所建立的数学回归模型能够较准确预测猕猴桃籽油的出油率。     

水酶法提取茶叶籽油工艺条件研究

采用水酶法提取茶叶籽油,通过单因素实验和正交实验优化提取工艺条件。结果表明,水酶法提取茶叶籽油优化工艺条件为:纤维素酶用量1.1%、果胶酶用量2.0%、蛋白酶用量0.2%,料液比1:6,酶解温度45℃、酶解pH值5.0、酶解时间8h,茶叶籽油得率28.64%。     

复合酶法提取辣木籽油及其体外抗氧化活性

以辣木籽为原料,采用水酶法提取辣木籽油,并对其体外抗氧化活性进行研究。以辣木籽油提油率为指标,确定复合酶的组合及比例(蛋白酶∶纤维素酶=2∶1),在单因素试验基础上,采用正交试验优化提取工艺。结果表明水酶法提取辣木籽油的最佳工艺为料液比1∶4 (g/mL)、pH 4、酶添加量3%、酶解温度55℃,在此条件下,辣木籽油的提取率为61.35%。水酶法提取的辣木籽油具有较强的抗氧化活性。5 mg/mL辣木籽油对羟自由基(·OH)和DPPH·清除率分别为80.30%和62.67%。     

水酶法提取橡胶籽油的工艺研究

研究水酶法提取橡胶籽油的工艺,采用单因素试验分别研究了原料处理方式、选用酶的种类、酶解条件对游离油得率的影响。在此基础上,采用正交试验确定了最佳提取工艺,即固液比1∶4,酶解时间8 h,酶添加量0.5%,酶解温度50℃,pH 5.0,之后,在5 000 r/min下离心30 min,并对乳状液进行加热破乳分离油相,破乳条件为沸水浴加热10 min,然后在6 000 r/min下离心10 min。在此条件下橡胶籽油的得率为89.3%。采用水酶法得到的橡胶籽油色泽浅黄透明,气味芬芳。     

响应面优化超声波辅助水酶法提取茶叶籽油工艺

利用响应面法(RSM)优化超声波辅助水酶法提取茶叶籽油工艺条件,在单因素试验基础上,选取复合酶用量、酶解pH、酶解温度、酶解时间为影响因子,茶叶籽油得率为响应值,应用Box-behnken中心组合试验设计建立数学模型,进行响应面分析。结果表明,超声波辅助水酶法提取茶叶籽油工艺优化条件为:高压蒸煮20min,超声处理20min,超声温度60℃,料液比1:5、复合酶用量1.75%,酶解pH4.6,酶解温度44℃,酶解时间6.9h。茶叶籽油得率为29.88%。     

水酶法提取火麻籽油工艺研究

以火麻籽为原料,利用水酶法提取火麻籽油。通过单因素实验及中心组合实验研究酶的种类、料液比、加酶量、酶解时间等因素对火麻籽提油率的影响。结果表明,酸性蛋白酶和纤维素酶按1∶1进行复配且先加酸性蛋白酶作为提取酶时,提取效果最好;在此基础上,通过响应面优化得到水酶法提取火麻籽油的最佳工艺条件为:复合酶添加量1.10%(w/w)、料液比1∶3.6g/mL、酶解时间3.8h,火麻籽油的提油率为75.64%。     

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.