红芸豆淀粉酶法提取工艺的研究

以红芸豆为原料,通过在传统的湿磨工艺中添加碱性蛋白酶来提取红芸豆淀粉。试验以淀粉提取率和淀粉纯度为考量指标,对pH、提取温度和酶量对淀粉提取率和纯度影响进行考察。在单因素试验基础上,通过响应面分析法确定红芸豆淀粉酶法提取工艺,同时建立红芸豆淀粉提取的数学模型并验证其可靠性。以pH、提取温度和酶量为自变量,探讨这3个因素交互作用和最佳提取条件,并对其进行验证。试验结果表明:红芸豆淀粉酶法提取的最佳工艺条件:pH为8.45、温度为55℃、酶量为2.5 mg/g,在此条件下红芸豆淀粉的提取率为53.51%,纯度为99.44%。     

超声波辅助酶法提取碎米中蛋白的研究

研究利用超声波辅助酶法提取稻谷加工业碎米中蛋白的工艺条件。探讨了加酶量、酶解时间、固液比、超声波功率及超声时间对蛋白提取率的影响。在单因素试验的基础上,通过正交试验得到最优提取条件为:最佳提取工艺条件是高温α-淀粉酶加酶量为20μL/g、酶解时间为2.5h、超声时间为24min,超声功率为380W,此条件下水溶性蛋白的提取率为91.19%。     

超声波辅助酶法提取青鱼鱼皮胶原蛋白工艺

以青鱼鱼皮为原料,考察超声波功率、超声波处理时间、加酶量、酶解温度、酶解时间、pH值对胶原蛋白提取率的影响,在单因素基础上对青鱼鱼皮胶原蛋白提取工艺进行正交试验和方差分析。结果表明,最佳提取工艺条件为:加酶量100 U/g、pH 7.5、酶解温度40℃、超声波处理时间50 min,胶原蛋白的提取率达45.3%。     

马铃薯渣中膳食纤维提取工艺的优化

目的:以马铃薯渣为原料,探究提取马铃薯渣中膳食纤维的最佳工艺条件。方法:通过生物法-酶法、超声波裂解、高速剪切等技术提取马铃薯渣中所含的膳食纤维,通过单因素试验和正交试验分析试验数据。结果:提取膳食纤维的最佳工艺条件为酶解p H为5、酶解温度45℃、酶添加量30U/g、酶解2.5h。结论:本研究膳食纤维的提取率达25.87%,并测得持水力和膨胀力分别为7.1g/g、7.5mL/g,该工艺条件可有效提取马铃薯渣中的膳食纤维。     

超声波协同复合酶法提取圣女果皂苷工艺优化

试验旨在优化超声波协同复合酶法提取圣女果皂苷的工艺。以圣女果皂苷提取率为评价指标,采用单因素试验和正交试验,确定最佳提取工艺参数。结果表明,提取过程中各因素对提取率的影响大小为:料液比酶浓度酶解时间超声时间;最佳超声波协同复合酶法提取优化工艺条件为:料液比1∶60 (g/mL)、酶浓度0.3%、提取时间1 h、超声时间20 min。该条件下圣女果皂苷提取率为0.37%。此次试验可为圣女果皂苷的工业化生产提供理论依据。     

酶法、酸法制备碎米多孔淀粉工艺研究及其比较

以碎米为原料,分别采用酶法、酸法制备多孔淀粉,通过单因素和正交试验,得到两种方法制备碎米多孔淀粉的最佳工艺条件,酶法制备碎米多孔淀粉最佳工艺条件为液料比4:1(mL/g)、加酶量23.0U/g、pH7.0、酶解温度60℃、酶解时间7h;酸法制备碎米多孔淀粉最佳工艺条件为液料比4:1(mL/g)、盐酸浓度0.4mol/L、酸解温度35℃、酸解时间6h。经比较酶法比酸法制得的多孔淀粉吸油率高13.3%。运用扫描电子显微镜对多孔淀粉的颗粒形态进行比较,结果表明酶法比酸法制得的多孔淀粉出孔率高、孔径大、孔穴深。     

超声波协同复合酶法提取香菇多糖的工艺优化

优化超声波协同复合酶法提取香菇中多糖成分的工艺。以香菇多糖提取率为评价指标,采用单因素试验和正交试验,确定最佳提取工艺参数。结果表明,超声波提取优化工艺条件为:料液比1∶15(g/mL),超声温度70℃,超声时间12 min。在此最佳超声提取条件下香菇多糖提取率为8.97%。在超声波优化的基础上,进行复合酶处理,最佳酶解工艺参数为:酶解时间50 min,复合酶(木瓜蛋白酶∶纤维素酶∶果胶酶=1∶1∶1,质量比)添加量3%,酶解温度60℃,酶解pH5.5,在此优化条件下香菇多糖提取率为12.46%。     

两种前处理方法提取辣椒中辣椒碱的最优工艺研究

以辣椒为原料,分别用纤维素酶乙醇提取法和超声波乙醇提取法对辣椒中的辣椒碱进行了提取并研究了两种工艺的最优工艺参数。实验结果表明:酶法提取的最优工艺条件为:酶解液初始pH5.5,酶量9mg/g,酶解时间1h,酶解温度40℃,此条件下辣椒碱的提取率为0.795%;超声波辅助提取最优条件为温度70℃,乙醇浓度70%,超声波功率60W,料液比1:11,此条件下辣椒碱的提取率为1.271%。     

酶法提取绿豆淀粉工艺研究

以绿豆为原料,对酶法提取绿豆淀粉工艺进行研究。通过单因素试验,研究酶解温度、酶解时间、蛋白酶添加量、料液比对淀粉提取率影响;通过四因素三水平正交试验确定酶法提取绿豆淀粉工艺最佳参数为:酶解温度46℃、酶解时间4.5 h、蛋白酶添加量700 U/g、料液比1∶3;在此条件下,绿豆淀粉提取率为96.97%。     

超声波辅助酶解法提取食用猪油工艺优化及胆固醇脱除

为开发猪油的提取新工艺,以猪脂肪组织为原料,采用超声波辅助中性蛋白酶酶解法提取食用猪油。在单因素试验的基础上,以猪油的提取率为考察指标,采用正交试验方法研究蛋白酶添加量、酶解时间、超声波功率和超声时间对猪油提取率的影响,并通过吸附条件的优化,研究β-环糊精、羧甲基纤维素及马铃薯变性淀粉3 种吸附剂对猪油胆固醇的脱除效果。结果表明：各因素对猪油提取率的影响从大到小依次为蛋白酶添加量＞酶解时间＞超声波功率＞超声时间;超声波辅助酶解提取食用猪油的最优工艺为蛋白酶添加量550 U/g、酶解时间80 min、超声波功率720 W、超声时间120 s,在此条件下,猪油的提取率为（95.14±1.65）%;3 种吸附剂对猪油胆固醇均具有明显的吸附效果,脱除能力依次为β-环糊精＞羧甲基纤维素＞马铃薯变性淀粉。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.