盐生野菜(黄须菜)干制工艺研究

黄须菜用500mg/kgZnCl2溶液(pH8～9)热烫90s,然后80℃入箱干燥15min后调至60℃,恒温干燥10～12h后回潮包装,即可得到色泽浓绿的合格产品。     

单粒莲子热风干燥特性及其干燥动力学

为了提高莲子干燥品质、缩短干燥时间并降低能耗,采用恒温和分段变温两种干燥方式对单粒莲子进行了50~90℃恒温和60(2~4 h)~80℃变温热风干燥试验,研究莲子表观变化、复水性、干燥能耗及干燥特性,计算不同干燥条件下的有效扩散系数和活化能。试验表明:在恒温干燥条件下,温度越高,干燥时间越短,而莲子色泽、复水性等品质则越差;在分段变温条件下,干燥时间较60℃恒温干燥缩短了,但品质均有所提高,60℃(3 h)~80℃变温干燥莲子的复水性优于60℃(2 h)~80℃和60℃(4 h)~80℃变温干燥,为169.41%,单位能耗比60℃恒温干燥减少2033 k J/g。根据菲克第二定律,得到莲子50~90℃恒温干燥有效扩散系数变化范围为1.79×10~(-9)~5.83×10~(-9) m~2/s,60℃(2~4 h)~80℃变温干燥平均有效扩散系数变化范围为2.97×10~(-9)~2.44×10~(-9) m~2/s。由Arrhenius方程建立有效扩散系数与温度的关系,得到莲子水分活化能为28.33 k J/mol。试验结果为莲子干燥工艺参数优化及干燥设备设计提供参考。     

腐竹热干燥特性及工艺优化研究

为缩短腐竹热干燥时间,得到色差,碎裂性及感官指标均最优的腐竹,对腐竹热干燥工艺进行优化。通过60、70、80、90、100℃恒温干燥腐竹,结果显示：90℃和100℃条件下可明显缩短干燥时间,但腐竹色差和感官效果不可接受;60～80℃范围内干燥,腐竹品质相近,色差较好,但易碎。设计高温→低温和低温→高温共5种温度梯度干燥方案,得到腐竹干燥最佳方案：100℃＋风＋1h→80℃＋风＋1.5h→60℃＋1.5h,共耗时4h。得到的干腐竹L＊值下降幅度小,a＊值上升幅度小,b＊值稳定;硬度和碎裂度值均达到最大值;感官上,腐竹表面出油很少,淡黄色,光泽好,豆香味浓郁,结实不易碎。     

热泵穿流干燥核桃的特性研究

为研究核桃深层装载形式下热泵穿流干燥特性,探讨干燥温度对不同堆积厚度层核桃含水率及干燥速率的影响。以陕西省"香玲"核桃为试验原料,研究装载深度为90 cm,干燥温度为35℃、45℃、55℃时厚度层为30、60、90 cm处核桃干燥特性。结果表明,核桃干燥过程中,各层均为降速干燥,干燥温度在干燥初期对干燥速率影响较大,55℃时核桃的最大干燥速率达到0.027 kg/(kg·h),分别是35℃和45℃时的1.34、1.21倍;在干燥中后期,温度增加对各层干燥速率的影响较小。     

鸭儿芹干制品的加工工艺研究

研究了鸭儿芹干制品的加工工艺及其加工过程中的护色 技术。结果表明,用0.15％NaHCO3烫漂液于90℃条件下 水浴烫漂90s,鸭儿芹的护色效果最佳。鸭儿芹冻干制品 较其热风干制品有更好的色泽、天然香味和质地。从成本 和制品品质综合考虑,选择干燥初期55℃／h,中期75℃／ 1h,末期55℃／1.5h的热风干燥方式为最好。     

微波和热风联合干燥薄层黄花菜的方法研究

在薄层黄花菜干制工艺中,选择的干制方法直接影响物料干燥时间的长短和产品质量的好坏.为了确定干燥薄层黄花菜的最佳干制方法,以湖南黄花菜的主栽品种鲜猛子花为材料,用热风干燥箱将受试材料在60、70、80、90℃及100℃等干燥温度条件下和用微波炉在高、中及低功率条件下进行干燥试验.结果表明热风干燥温度小于80℃时,干燥时间长(3.5～4h),生产效率低,但产品质量好;干燥温度大于90℃时,干燥时间短(1.5～2h),生产效率高,但产品质量差,因而薄层黄花菜的最佳干燥温度为90℃;与热风干燥相比,无论哪种微波功率干燥时间都较短,但产品质量差;先微波干燥再热风干燥可显著缩短干燥时间,但产品质量不好,先热风干燥再微波干燥不但明显地缩短干燥时间,而且可保证产品质量.同时建立了黄花菜薄层干燥的数学模型MR=(r=e-4.3154+0.05631T,n= 0.5228+ 0.01007T), 可较好地描述干燥过程中物料含水率与干燥时间的关系.     

速煮紫薯丁的干燥方法研究

通过对比热风干燥、真空干燥、冷冻加热风干燥对速煮紫薯丁的品质影响,选择适合速煮紫薯丁的干燥方法,并对其进行优化.结果表明:(1)采用热风干燥的工艺生产的速煮紫薯丁品质优于其他方法.原料经处理后,先90℃热风干燥2.5h至水分质量分数30％,再70℃热风干燥4h至水分质量分数10％,制成的速煮紫薯丁具有良好的复水性,花青素保留率也较高;(2)在相同干燥温度条件下,花青素保留率随水分的降低而降低;(3)速煮紫薯丁干燥水分临界点为质量分数30％.     

酱油黄豆曲热风干燥工艺研究

研究以酱油黄豆曲为试验材料,对其进行恒温热风干燥和分阶段控温热风干燥的对比试验,找出最优热风干燥黄豆曲的工艺。试验结果表明:分阶段控温干燥优于恒温干燥,曲料经分阶段控温干燥后蛋白酶相对酶活力较高,干燥时间也较短。最优的黄豆曲热风干燥工艺:初始温度42℃10h,中间温度55℃6h,最终温度62℃4h。干燥结束后黄豆曲含水率为10.19%,中性、酸性蛋白酶相对酶活力分别为91.40%,78.64%。     

热溶胶结合高温干燥降低琼脂溶胶温度的研究

琼脂在食品工业中具有重要的应用价值,将琼脂溶化温度降低至90℃以下有利于琼脂在乳制品中的应用.文章探究了加热溶胶后高温干燥对琼脂性质的影响,并探索琼脂与常用水溶性胶体复配后经加热溶胶、高温干燥制备低温溶解琼脂复配胶体的技术.研究发现琼脂在热处理时间1.5 h、热处理温度120℃条件下进行热处理并经高温烘干后其溶化温度最...     

海藻糖对纤维素酶的干燥保护作用

纤维素酶液中加入不同剂量的海藻糖作为干燥保护剂,喷雾干燥后纤维素酶活力的回收率由空白对照的63.7%提高到89.0%;硅藻土吸附酶液经50℃干燥后,空白对照的酶活力回收率为60.5%,海藻糖组的回收率为65.8%;90℃10min造粒后,纤维素酶活力的回收率由空白对照的62.4%提高到92.7%。造粒的纤维素酶置50℃保存240h后,空白对照的剩余酶活力为70.5%,而海藻糖组的酶活力仍保持在81.2%。结果表明,海藻糖在纤维素酶的干燥和保存过程中有较好的保护效果。     

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