柑橘生物酶法脱囊衣技术研究

本实验进行了生物酶法脱除柑橘囊衣的优化工艺条件研究。同时利用扫描电镜观察了酶解过程中囊衣结构变化。结果表明,复合酶制剂脱囊衣的优化酶解工艺为酶浓度0.35%(g/L)、变电频率40Hz、pH4.5、在40℃下酶解50min。柑橘生物酶法脱囊衣桔瓣呈现优良的外观,组织紧密和光泽好。     

酶法脱囊衣工艺优化及对甜橙囊胞品质的影响

以甜橙为原料,优化酶法脱囊衣工艺条件,在此基础上比较研究酶法与酸碱法脱囊衣对甜橙囊胞品质的影响。结果表明,酶法脱囊衣优化工艺参数为戊聚糖复合酶添加量0.35%、酶解温度50 ℃、酶解时间40 min。酸碱法脱囊衣后,囊胞汁液中VC、总酸、还原糖、总糖和香气成分的保存率分别为78.71%、56.01%、75.17%、79.45%、82.72%;酶法脱囊衣后,囊胞汁液中主要营养成分的保存率均可达96%以上,香气成分保存率也提高了15.46%。综合各项指标,酶法脱囊衣效果优于酸碱法。     

橘瓣酶解脱囊衣工艺及其罐头品质的研究

研究利用酶制剂脱除温州蜜柑橘瓣囊衣的方法。通过试验筛选最佳的酶及酶解工艺,结果表明使用和氏璧果胶酶,在酶液质量分数1.0%、pH 3.5、酶解温度45℃、酶解时间45 min条件下,可以得到较佳的脱囊衣效果;酶解过程中使用超声波辅助酶解,可以提高酶解效果。通过感官分析、理化指标检测,对比酶解脱囊衣和传统酸碱脱囊衣的橘瓣罐头的品质,结果显示酶解工艺提高橘瓣破碎率5.5%,降低维生素C含量20.4%,而不影响橘瓣的硬度、色差、滋味和气味。温州蜜柑橘瓣的酶解脱囊衣工艺可用于工业化生产橘瓣罐头。     

山药多糖脱蛋白方法的研究

以蛋白脱除率和多糖保留率为指标,通过比较Sevage法、三氯乙酸(TCA)法、胰蛋白酶法、十六烷基三甲基溴化铵(CTAB)法、胰蛋白酶-TCA联用法、胰蛋白酶-Sevage联用法、胰蛋白酶-CTAB联用法,对山药块茎多糖进行脱蛋白研究。试验结果表明:胰蛋白酶-TCA法脱蛋白的效果最好,蛋白脱除率为87.25%,多糖保留率为92.48%,而且试验耗时短,操作简单。其最佳脱蛋白条件为:胰蛋白酶用量为0.4 mL,酶解时间为45 min,酶解pH为7.5,酶解温度为37℃,TCA浓度为6%。     

灵芝多糖酶解-Sevage法联合脱蛋白工艺研究

本文采用正交试验优化Sevage法对灵芝多糖脱蛋白的工艺参数,在最佳的工艺参数下,分别研究木瓜蛋白酶、胰蛋白酶和链霉蛋白酶在脱蛋自作用中的最适酶液浓度和酶解时间,然后进一步采用正交试验优化酶解-Sevage法联合脱蛋白工艺参数,实验结果表明：在酶解-Sevage法联合脱蛋白的工艺中,酶解时间及胰蛋白酶浓度对灵芝多糖脱蛋白率起主要作用,最佳工艺参数为木瓜蛋白酶浓度0．8％;胰蛋白酶浓度为0．8％;链霉蛋白酶浓度1．0％;各自酶解时间4h;脱蛋门次数3次,多糖蛋白脱除率为99．64％,与单一Sevage法脱蛋白比较,多糖中的蛋白基本可以脱除,且多糖损失率降低了20．64％,说明酶解和Sevage法联合使用对灵芝多糖具有很好的脱蛋白效果。     

蕨麻粗多糖酶法脱蛋白工艺

摸索蕨麻粗多糖脱蛋白工艺条件,为蕨麻粗多糖的纯化提供理论依据。实验选取了木瓜蛋白酶、中性蛋白酶、胰蛋白酶进行蕨麻粗多糖脱蛋白实验,采用正交试验研究了酶添加量、酶解温度、酶解时间、pH值对蕨麻粗多糖脱蛋白工艺的影响。选取胰蛋白酶进行脱蛋白实验,最佳脱蛋白条件为酶添加量0．25g、酶解温度30℃、酶解时间4h、pH值7．8。     

速冻蜜橘酶法脱除囊衣研究

研究利用酶法脱除速冻蜜橘囊衣的方法.通过试验筛选出合适的酶,在单因素试验的基础上进行正交试验,确定最佳酶解工艺.结果表明,果胶酶A和纤维素酶按2:1混合.去囊衣效果最理想;最佳的酶解工艺参数为:酶浓度0.3%(g/L),温度50℃,PH值4.5,酶解时间60 min.酶法去囊衣作用效果明显,品质良好,外观整齐,散瓣率低,安全性高,应用方便且对环境无污染,是一个切实可行的方法.     

复合酶解法脱除柑橘囊衣工艺研究

以浙江产中晚熟温州蜜柑为试材,采用L_9(3~4)正交实验设计对复合酶解脱除柑橘囊衣工艺参数进行优化,并提出以酶解产物中还原糖含量作为酶解效果的评价指标.结果表明:pH3.4,温度50℃,果胶酶与纤维素酶的使用比例为1:1,酶解时间达到38min,可得到完整而紧实的全去囊衣产品.     

红松松塔粗多糖酶法脱蛋白工艺的研究

摸索红松松塔粗多糖脱蛋白工艺条件,为松塔粗多糖的纯化提供理论依据。从三种蛋白酶中筛选出脱蛋白效果最佳的蛋白酶为胰蛋白酶,并利用单因素和正交试验研究了酶添加量、酶解温度、酶解时间和pH值对松塔粗多糖脱蛋白工艺的影响。研究结果表明,胰蛋白酶最佳脱蛋白条件为pH值为4．5,酶添加量为0．10％,酶解温度为60℃和酶解时间为2．0h。     

柑桔罐藏酶法去囊衣试验研究

本试验着重研究了果胶酶(Pectinase,Serva),纤维素酶(Cellulase,Yakult)及混合酶(包括果胶酶,纤维素酶,半纤维素酶及脂肪酶)用于温州蜜柑(Satsuma mandarin)桔瓣去囊衣处理的最佳工艺条件,比较了不同品种原料除去囊衣的难易程度,探讨了金属高于,表面活性剂对酶解去囊衣时间的影响,并对酶处理前后囊衣的超微结构进行了电镜观察。本研究结果表明:酶法脱囊衣所需时间明显少于传统酸碱法处理,营养成分损失少,V。保存率在90%以L,糖龄比无明显变化,而且颜色更加美观,风味更为优美,口感也优于酸碱处理。电镜观察结果表明:果胶酶处理后,囊衣细胞间的果胶质被水解,纤维素酶水解细胞壁中纤维素,造成整个囊衣结构崩溃。     

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