褐变抑制剂对干制香蕉片护色效果的影响

为了提高香蕉片干制后的颜色品质,获得最佳护色方法,以褐变度和L*值为考察指标,研究植酸、抗坏血酸、氯化钠、EDTA、柠檬酸5种褐变抑制剂对干制香蕉片颜色品质影响,并优选出提高干制香蕉片颜色品质的护色方法。结果表明:单一护色剂护色效果依次为植酸柠檬酸EDTA氯化钠抗坏血酸,将鲜切香蕉片放入植酸(质量分数为0.9%)和柠檬酸(质量分数为0.3%)组成的复合护色液中浸泡20 min,干制后的香蕉片L*值达65.93,褐变抑制率达84.4%。     

鲜切富贵菜护色保鲜剂组合的筛选及其对生理指标的影响

本文以富贵菜[Gynura divaricata(L.)DC.]为实验材料,通过正交试验优选出最佳组合护色保鲜剂,并使用其保鲜鲜切富贵菜,在贮藏期间定期检测鲜切富贵菜的色泽(L值)、叶绿素含量、丙二醛含量、维生素C含量及多酚氧化酶和过氧化物酶的活性。结果表明:对鲜切富贵菜外观色泽影响的主次因素依次为:A(抗坏血酸)>B(柠檬酸)>C(氯化钙)>D(植酸),复合护色保鲜剂最佳组合:0.1%抗坏血酸+0.1%柠檬酸+2.0%CaCl2+0.4%植酸。对鲜切富贵菜的生理品质指标的影响发现,该护色保鲜剂可以较好地抑制鲜切富贵菜的褐变和PPO活性,保持较高的叶绿素含量、Vc含量、POD活性和较低的丙二醛含量。     

茄子鲜切片护色技术的研究

茄子是具备较高营养价值和药用价值的夏秋两季经常食用的蔬菜。利用茄子生产鲜切片是一种新兴的净菜生产方式。然而,鲜切茄片在贮藏和货架销售过程中发生褐变、萎蔫导致营养物质损失、品质劣变。使用保鲜护色剂是延缓组织衰老、延长货架寿命的有效措施。本文以几种常见天然护色剂复配,通过单因素试验和正交试验对茄子鲜切片的护色技术进行研究,结果表明各因素对茄子鲜切片护色效果的影响顺序为大蒜提取液植酸壳聚糖抗坏血酸,最佳护色工艺条件为A3B2C1D3,即复合护色液的各成分配比为大蒜提取液8%、植酸0.2%、壳聚糖0.15%、抗坏血酸0.1%。方差分析表明大蒜提取液在0.1显著水平上达到了差异显著。     

复合护色液对鲜切牛蒡的防褐变研究

研究了影响鲜切牛蒡护色效果的因素,在单因素试验的基础上进行正交试验,通过感官评定来确定最佳护色工艺。试验结果表明,单一的0.6%抗坏血酸、1.0%柠檬酸和1.0%的亚硫酸氢钠处理均能很好地抑制鲜切牛蒡褐变,三种护色剂对护色效果的影响顺序为亚硫酸氢钠>柠檬酸>抗坏血酸;在考虑护色时间和料液比的基础上,通过L9(34)正交试验,确定了鲜切牛蒡的最佳护色组合为A1B3C3,即0.4%抗坏血酸、0.8%柠檬酸、0.15%亚硫酸氢钠按1:2的料液比浸泡30 min,可以有效地防止鲜切牛蒡加工过程中的褐变。     

响应面法优化山药粉的护色工艺

以鲜山药为原料,采用热风干燥法制备山药粉。在单因素实验的基础上,通过响应面法研究了柠檬酸、抗坏血酸、植酸、氯化钙4因素对山药粉白度的影响,可以得出热风干燥法制备山药粉的最优护色工艺条件为:柠檬酸浓度1.28%、L-抗坏血酸浓度0.05%,植酸浓度0.12%,氯化钙浓度0.3%,山药粉的实际甘茨白度为23.56。实验研究表明,以甘茨白度作为山药粉色泽评判的指标,并用响应面法对山药护色工艺的优化合理可行,为山药粉护色工艺提供一定的理论支持。     

均匀设计法优化鲜切山药的护色工艺

鲜切山药在空气中容易被氧化产生褐色素,影响其品质。通过单因素实验,研究了常用护色剂EDTA-2Na、抗坏血酸、氯化钠及柠檬酸对鲜切山药的护色效果,并确定了其单独使用时的较佳浓度。通过均匀设计安排实验,对鲜切山药的护色工艺进行优化,得到优化护色配方:0.8%EDTA-2Na,2.0%柠檬酸,0.2%抗坏血酸。通过对照实验,研究了不同前处理0.005%,0.010%Na Cl O消毒及65℃烫漂对鲜切山药的护色效果,结果表明:0.005%,0.010%Na Cl O消毒及65℃烫漂对鲜切山药均具有良好的护色效果,其中0.005%Na Cl O效果优于0.010%Na Cl O。     

柠檬酸亚锡二钠对鲜切莲藕护色作用的研究

柠檬酸亚锡二钠(DSC)是一种新型护色剂。将DSC用于鲜切莲藕预处理阶段,抑制莲藕多酚氧化酶活力及褐变,探讨影响DSC对鲜切莲藕片护色作用的因素,并与其他常用护色剂的护色效果进行对比。结果表明:DSC对鲜切藕产品低温保藏期间的褐变和多酚氧化酶活力都有很好的抑制作用,在pH 3～6条件下用0.05%～0.2%DSC浸泡液处理15min后,鲜切藕产品可保持较低的褐变度和多酚氧化酶活力,同时在4℃、20d内DSC的护色效果稳定;与其他常用护色剂比较,在0.1%的等量护色剂浓度下,DSC护色效果优于柠檬酸、抗坏血酸、异抗坏血酸钠,与亚硫酸氢钠效果相当。     

护色剂对鲜切莴笋褐变的影响

运用正交试验方法确定最佳护色配方,研究其对鲜切莴笋贮藏期间品质变化的影响.结果表明,在鲜切莴笋贮藏过程中,用0.4%半胱氨酸、0.6%柠檬酸、0.7%抗坏血酸、1.5% 氯化钙的复合护色液浸泡8 min,能有效的抑制鲜切莴笋褐变,抑制PPO活性,提高鲜切莴笋的感官品质.     

鲜切荸荠的护色工艺研究

以新鲜荸荠为原料,结合单因素实验和正交实验,根据褐变度研究酸液烫漂和护色剂浸泡对荸荠护色效果的影响,筛选出鲜切荸荠的最佳护色组合。结果表明,酸液漂烫和护色剂浸泡对鲜切荸荠都具有较好的护色效果。鲜切荸荠的最佳漂烫工艺条件为70℃下0.3%柠檬酸溶液中漂烫90 s;最佳护色工艺条件是将漂烫过的荸荠浸入1.0%氯化钙溶液+0.15%亚硫酸氢钠溶液+0.3%植酸溶液中浸泡20 min。     

一种复配保鲜剂对鲜切油豆角贮藏品质的影响

以东北油豆角为原料,研究抗坏血酸、植酸和壳聚糖三种保鲜剂的复配对鲜切油豆角贮藏期间品质的影响,以蒸馏水为对照组,选取褐变度为指标进行单因素及正交试验,并选取叶绿素含量、抗坏血酸含量等作为指标,验证复配保鲜剂的保鲜效果。结果表明,抗坏血酸、植酸和壳聚糖三种保鲜剂的最佳浓度分别为0.25%,0.25%和1.0%;正交试验得出,鲜切油豆角的最佳复配保鲜剂由1.0%的壳聚糖溶液、0.30%抗坏血酸溶液和0.30%植酸溶液组成,影响顺序为:抗坏血酸植酸壳聚糖,得到的复配保鲜剂对鲜切油豆角有较好的保鲜作用。     

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.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the