高温蒸煮结合酶解改性豆渣膳食纤维

采用高温蒸煮结合纤维素酶酶解的方法,改性豆渣不溶性膳食纤维,制备水溶性膳食纤维。以水溶性膳食纤维的得率为考察指标,分别对高温蒸煮改性、高温蒸煮结合纤维素酶酶解改性工艺进行研究,并应用正交试验设计法优化高温蒸煮结合纤维素酶酶解改性工艺。结果显示,在优化的高温蒸煮结合纤维素酶酶解改性的反应条件下,即固液比为1:20 g/mL、酶解温度为45℃、酶底比为0.3%、酶解时间为4 h、pH值为5.0时,改性后水溶性膳食纤维的得率为31.89%,明显高于单独采用高温蒸煮法(130℃、60 min)改性的水溶性膳食纤维得率(10.85%)。     

复合纤维素酶法制备玉米水溶性膳食纤维

以玉米皮水不溶性膳食纤维为原料,对复合纤维素酶法制备水溶性膳食纤维(SDF)进行了研究。采用六偏磷酸钠及高温蒸煮等处理方法强化酶解过程以提高水溶性膳食纤维得率。结果表明,高温蒸煮有助于提高玉米皮水溶性膳食纤维得率,条件为121℃,3 h。在单因素实验的基础上,采用L9(34)正交实验对复合纤维素酶法制备水溶性膳食纤维的条件进行优化。结果表明,玉米水溶性膳食纤维的较佳提取条件为:复合纤维素酶的添加量2%,底物浓度40 g/L,酶解温度55℃,pH4.0,酶解11 h。在此条件下,玉米SDF得率达到10.37%。     

双酶改性制备玉米皮水溶性膳食纤维的工艺研究

以玉米皮超声提取天然水溶性膳食纤维后的副产物——不溶性玉米皮渣为试材,应用木聚糖酶和纤维素酶组合酶解制备水溶性膳食纤维,采用单因素和正交试验组合研究确立一套由水不溶性膳食纤维改性制备水溶性膳食纤维制备工艺。结果表明,最佳工艺参数为纤维素酶添加量40mg/g 底物、木聚糖酶添加量40mg/g 底物、料液比1:14(g/ml)、酶解时间90min,水溶性膳食纤维得率为5.96%。     

生物酶法改性玉米皮渣膳食纤维工艺研究

该研究以玉米皮渣为原料,经处理后获得不溶性膳食纤维,采用生物酶法对膳食纤维进行改性处理,主要研究双酶酶解工艺对水溶性膳食纤维得率的影响。结果表明,木聚糖酶和纤维素酶酶解玉米皮渣可显著提高可溶性膳食纤维得率,最佳的酶解条件为纤维素酶添加量为30 mg/g底物、木聚糖酶添加40 mg/g底物、料液比1∶12（g/mL）、酶解时间90 min,在该条件下,水溶性膳食纤维得率为2.996%。     

豆渣可溶性膳食纤维酶法制备工艺及其品质分析

为了获得高得率的豆渣可溶性膳食纤维,以碱处理豆渣制备可溶性膳食纤维后剩余的不溶性残渣为原料,采用纤维素酶对其进行酶解改性。通过单因素试验和响应面优化试验,研究了不同酶解条件对豆渣可溶性膳食纤维得率的影响。结果表明:对豆渣可溶性膳食纤维得率的影响因素依次为加酶量>酶解时间>酶解温度>酶解pH,最佳酶解工艺条件为:加酶量1.80%,酶解时间3.5 h,酶解温度48℃,酶解pH4.8。在此条件下,豆渣可溶性膳食纤维得率可达到7.64%,且其品质符合国家粮食行业标准规定的指标。扫描电镜结果表明,酶法制备的豆渣可溶性膳食纤维的颗粒较小,呈现蜂窝状,有利于其水合特性的提高。     

酶法制备豆渣水溶性膳食纤维

采用酶法从豆渣中提取水溶性膳食纤维,对四种纤维素酶进行了筛选,并确定了最佳酶制剂.研究了料水比、纤维素酶的添加量、反应时间、反应温度和溶液pH 5个因素对水溶性膳食纤维提取量的影响,通过单因素和正交实验,确立了制备水溶性膳食纤维的最佳工艺条件.在此工艺条件下,水溶性膳食纤维的得率为10.45%.     

玉米皮水溶性膳食纤维的酶法制备

本研究采用复合纤维素酶和木聚糖酶对经过处理的玉米皮进行酶解,制备玉米皮水溶性膳食纤维(SDF),通过单因素和正交试验确立了一套最佳制备工艺。结果表明,复合纤维素酶和木聚糖酶混合改性制备SDF的最佳工艺参数为:酶添加量0.8%、酶解温度58℃、酶解pH 5.5、酶解时间8 h,SDF得率为13.82%。本方法中,玉米皮表面蛋白和淀粉杂质去除比较充分,产品纯度和得率高,工艺简单,适应工业化生产,得到的SDF产品黏度低、持水力及溶胀性好。     

木聚糖酶改性玉米麸皮膳食纤维粉工艺研究

以玉米麸皮为原料制备膳食纤维粉,采用木聚糖酶对其进行改性,以提高膳食纤维品质。通过木聚糖酶法,可溶性膳食纤维得率为27.49%;其最适反应条件为:木聚糖酶添加量25.7 U/g、酶解时间1.96 h、酶解温度56.09℃、酶解pH 4.68。     

酶法制取玉米水溶性膳食纤维的研究

采用纤维素酶和木聚糖酶对脱去淀粉和蛋白质的玉米皮进行处理, 以得到水溶性膳食纤维.通过正交试验探究酶解过程的最佳工艺条件,从而提高不溶性膳食纤维的转化率.结果表明,在温度为45℃、pH值为4.8、料液比为1:12、酶解时间为8h、纤维素酶和木聚糖酶的添加量分别为1%和0.3%时,转化率最高,可以达到6.57%.其中,纤维素酶的添加量对试验影响显著性最大.     

以大豆皮为原料酶法制备水溶性膳食纤维工艺研究

研究了以大豆皮为原料酶法制备水溶性膳食纤维（SDF）的工艺,并对影响SDF得率的主要因素进行了探讨。结果表明,影响SDF得率的主要因素依次为酶解时间、pH、酶添加量、酶解温度;通过正交试验得到优化工艺条件为酶解时间18h,pH4,酶添加量2．5％,酶解温度50℃。在优化条件下,SDF得率为11．84％,纯度高达76．08％。     

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.