鸭骨泥酶解条件优化及游离氨基酸组成分析

以鸭骨泥为原料,预处理后经定向酶解得到富含氨基酸的酶解液,从而为制备热反应型肉味香精提供底物。主要研究了预处理温度和时间对鸭骨泥酶解作用的影响,通过正交实验优化了酶法水解的条件,并对酶解液的游离氨基酸组成进行了测定。实验结果表明:鸭骨泥最佳预处理温度和时间为80℃,40min;鸭骨泥最佳酶解条件为胰蛋白酶用量10000IU/g,酶解温度45℃、pH7.5,料液比1:30,酶解时间5h,在此最佳酶解条件下,鸭骨泥水解度达63.18%,平均肽链长度1.58%,氮回收率59.43%;鸭骨泥酶解液含有16种氨基酸,其中必需氨基酸有7种,必需氨基酸占氨基酸总量的56.26%。     

黑大蒜粉喷雾干燥工艺条件研究

为采用喷雾干燥方法制备黑大蒜粉,在单因素实验的基础上,采用正交实验对影响黑大蒜粉制备质量的进风温度、进料流量、黑蒜液可溶性固形物含量、β-环糊精添加量进行了研究,得到最佳工艺条件:进风温度210℃,进料流量28 mL/min,黑蒜液可溶性固形物含量18％,β-环糊精量6％.该条件下制备的黑蒜粉溶解性好、香味浓,干燥过程中不粘壁.     

喷雾干燥法制备鸭血粉的工艺研究

以新鲜鸭血为原料,采用喷雾干燥法制备鸭血粉,研究了鸭血浓度、进风温度和进料速度对鸭血粉喷雾干燥效果的影响。试验结果表明:喷雾干燥法可用于制备鸭血粉,其最佳制备工艺参数为鸭血体积分数65%,进风温度190℃,进料速度0.057 ml/s,在此最佳制备工艺参数下制得的鸭血粉感官质量较高,水分含量低,溶解度较高;并初步建立了鸭血粉的质量指标。     

基于响应面分析法的小球藻藻粉喷雾干燥工艺优化

以小球藻藻粉得率为主要目标,选取进料浓度、进风温度和进料速度三个因素进行中心组合实验(Box-Benhnken),通过响应面分析法对小球藻藻粉干燥工艺进行优化研究。利用Design Expert软件,得到了小球藻粉最佳的喷雾干燥条件:进风温度200℃,进料浓度77.8g/L,进料速度100mL/h。在此工艺条件下,喷雾干燥所得的藻粉得率最高,其最大得率理论值为48.18%,与实测值47.20%基本一致。     

枇杷叶速溶粉制备工艺优化及其性能研究

为采用喷雾干燥制备速溶枇杷叶粉,采用正交实验对影响溶解度的进风温度、进料流量、枇杷叶提取物固形物含量、β-环糊精添加量进行研究,并对喷雾干燥制备的枇杷叶粉的特性进行研究。结果表明:喷雾干燥制备枇杷叶速溶粉的最佳工艺条件为:进风温度210℃、进料流量28mL/min、固形物含量23%、β-环糊精量5%。该条件下制备的速溶粉,粒度(D90)=232.5±2.1μm,总三萜、总黄酮含量分别达到15.52±1.53mg/kg、9.02±1.13mg/kg,溶解性达到(3.1±0.1)s,表明喷雾干燥是速溶枇杷叶粉制备的适宜方法。     

骨素酶解液喷雾干燥工艺的响应面法优化

为了降低半固态骨素类香精香料的贮运成本,延长产品保藏期,以骨素酶解液为原料,在单因素实验基础上,采用响应面法优化了骨素酶解液的喷雾干燥工艺.以风速、进料量、进风温度为影响因素,骨素酶解液的L值、a值、b值及风味、色泽为优化指标.拟合结果发现,风速、进料量、进风温度与骨素酶解液的b值及风味间存在显著相关性(p＜0.05),验证实验结果表明,所得模型具有一定可靠性.在拟合基础上,对骨素酶解液的喷雾干燥工艺进行了限值优化,结果表明,风速86.63m/s,进料量60.00mL/min,进风温度118.93℃为骨素酶解液的最优喷雾干燥工艺.此时骨素酶解液的风味得到了较好保留,色泽破坏较少.     

草莓速溶粉喷雾干燥工艺的研究

探究草莓速溶粉的最佳喷雾干燥工艺条件,以草莓为原料,进行草莓速溶粉喷雾干燥工艺优化研究。以草莓速溶粉出粉率为指标,对进样流量、β-环糊精添加量、可溶性固形物含量和进风温度4个因素根据Box-Behnken中心组合试验设计原理进行响应面分析。结果表明:进料流量850 mL/h、β-环糊精添加量0.7%、可固形物含量16%、进风温度180℃、出粉率达到44.27%此条件下喷雾干燥效果最佳。     

喷雾干燥法生产胡萝卜粉的工艺研究

采用正交试验对喷雾干燥法制备胡萝卜粉的工艺条件进行研究,结果表明,喷雾干燥最佳工艺参数是进风温度190 ℃,进料速率25 mL/min,β-环糊精添加量8%,此时集粉率可达22.8%.     

鹅骨泥酶解条件优化及游离氨基酸组成分析

以鹅骨泥为原料,预处理后经定向酶解得到富含氨基酸的酶解液,为制备热反应型肉味香精提供底物。主要研究了预处理温度和时间对鹅骨泥酶解作用的影响,通过正交实验优化了酶法水解的条件,并对酶解液的游离氨基酸组成进行了测定。实验结果表明:鹅骨泥最佳预处理温度和时间为80℃,40 min;鹅骨泥最佳酶解条件为胰蛋白酶用量10 000 IU/g,酶解温度45℃、pH值7.5,料液比1∶30,酶解时间5 h,在此酶解条件下,鹅骨泥水解度达63.09%,平均肽链长度1.59%,氮回收率56.78%;鹅骨泥酶解液含有16种氨基酸,其中必需氨基酸有7种,必需氨基酸占氨基酸总量的61.35%。     

南极磷虾蛋白粉的制备工艺

以南极磷虾为原料,研究其酶解及喷雾干燥工艺,以及南极磷虾蛋白粉的营养成分指标。研究结果表明,采用木瓜蛋白酶酶解南极磷虾的最佳工艺参数:每100 g南极磷虾肉糜中木瓜蛋白酶酶用量3 000 U/g蛋白、料液比为1∶2(g∶m L)、温度55℃、p H 6. 5、时间2 h;南极磷虾酶解液最佳喷雾干燥条件:进料量250 g/L、进风温度180℃、进料温度30℃、进料速度12 m L/min;南极磷虾蛋白粉为白色粉状,吸湿性较强。南极磷虾蛋白粉脂肪含量较低且具有丰富的矿物元素,关于南极磷虾及其高附加值产品的研究具有很强的开发前景。     

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.