乳清酸奶的研制

利用干酪副产物乳清,添加部分大豆蛋白制备发酵酸奶,通过正交试验优化乳清酸奶的配方.结果表明,乳清酸奶的最佳配方为大豆蛋白液浓度为14%,大豆蛋白液与乳清的比例为1:2,加糖量为7%,混合菌种接种量为2.5%,发酵时间为4h.     

乳清多肽的制备及其发酵饮料的开发

研究了乳清多肽的制备、性质及其发酵饮料的开发,结果表明,碱性蛋白酶比中性蛋白酶水解乳清蛋白的能力强,且更经济,水解最佳条件为加酶量为7000(U/g蛋白)、底物添加量为5%、水解温度为60℃、水解初始pH值为8.5,最大乳清蛋白水解度可达到22.45%。最优酒精发酵条件为接种量5%、初始pH7.5、温度22℃、时间45h。乳清多肽发酵饮料的配方为酸量0.1%,蔗糖量为8%,-β环状糊精量为0.5%。     

响应面法优化乳清梨酒发酵工艺的研究

以乳清粉作为试验原料,通过单因素试验研究了酵母菌接种量、发酵温度、发酵时间、蔗糖添加量对乳清梨酒发酵的影响,并且借助响应面设计,对乳清梨酒发酵工艺进行了优化。结果表明,乳清梨酒最佳发酵条件为接种量6%、发酵温度28 ℃、发酵时间79 h。在此最佳条件下,乳清梨酒酒精度为8.10%vol,酸度17.72 g/L。乳清梨酒呈淡黄绿色,酒香清雅,酒体醇厚,酸甜爽口。     

发酵型乳清沙棘饮料的研制

以经过蛋白澄清的乳清作为底物,采用混合乳酸菌对其进行发酵,并利用发酵乳清与沙棘汁调配制成发酵型沙棘汁乳清饮料。试验中,通过正交试验确定了混合发酵剂对乳清发酵的最佳条件为:嗜热链球菌与保加利亚杆菌比例1∶2,接种量4%,发酵温度38℃。在该条件下发酵4h,pH达到4.96,酸度达到26.8°T,乳糖含量为6.81%。同时,通过正交试验确定了对产品品质影响最大的沙棘汁、蔗糖和稳定剂的添加量,得到发酵型沙棘汁乳清饮料的最佳配方为沙棘汁7.5%、蔗糖6%、稳定剂0.3%。     

瑞士乳杆菌发酵乳清产物抗氧化活性的条件优化

应用产蛋白酶活力强的瑞士乳杆菌发酵乳清,讨论了发酵时间、发酵温度、发酵初始pH值和瑞士乳杆菌接种量等条件对产物抗氧化活性的影响。在单因素实验的基础上,进行正交实验,得到抗氧化活性最高产物的发酵条件为发酵温度37℃、乳清初始pH值为6.0、瑞士乳杆菌接种量(体积分数)5%和连续培养18 h。在此条件下,发酵产物的羟自由基清除能力达到54.73%。证明了瑞士乳杆菌发酵乳清产物具有优于未发酵乳清的较强抗氧化活性,在现有酶解法的基础上开辟了制备乳清源抗氧化肽的新途径。     

乳清多肽的制备及乳清多肽酒的研制

采用蛋白酶水解乳清粉,并对乳清多肽进行酵母菌发酵,并对发酵所得乳清酒进行风味调配。乳清粉最佳的水解条件为:[E/S]=1%、T=60℃、pH=9.0、时间=120min,水解度为DH=21.22%。乳清多肽酒的最优发酵条件:接种量为5%、起始pH为7.5、温度为22℃、发酵60h,酒度可达到3.9。多肽乳清酒的最佳基本调配是:酸量(苹果酸:柠檬酸=1:1)为0.1%、蔗糖为7%、环状糊精为0.6%。     

乳清多肽酒的开发

采用蛋白酶水解乳清粉,并对乳清多肽进行酵母菌发酵,对发酵所得乳清酒进行风味调配。乳清粉最佳的水解条件为:[E/S]=1%、T=60℃、pH=9.0、时间=120min,水解度为DH=21.22%。乳清多肽酒的最优发酵条件:接种量为5%、起始pH为7.5、温度为22℃、发酵60h,酒度可达到3.9。多肽乳清酒的最佳基本调配是:酸量(苹果酸∶柠檬酸=1∶1)为0.1%、蔗糖为7%、环状糊精为0.6%。     

乳清多肽酒的开发

采用蛋白酶水解乳清粉,并对乳清多肽进行酵母菌发酵,对发酵所得乳清酒进行风味调配。乳清粉最佳的水解条件为:[E/S]=1%、T=60℃、pH=9.0、时间=120min,水解度为DH=21.22%。乳清多肽酒的最优发酵条件:接种量为5%、起始pH为7.5、温度为22℃、发酵60h,酒度可达到3.9。多肽乳清酒的最佳基本调配是:酸量(苹果酸∶柠檬酸=1∶1)为0.1%、蔗糖为7%、环状糊精为0.6%。      

固定化乳酸菌发酵乳清饮料的研究

应用海藻酸钠-壳聚糖固定化乳酸菌进行发酵乳清饮料研究。结果表明,固定化乳酸菌发酵乳清饮料的最佳工艺条件为:发酵温度42℃,接种量32g,保加利亚乳杆菌︰嗜热链球菌(L.b︰S.t)为1︰2;发酵乳清饮料的最佳调配方案:柠檬酸为0.2%,蔗糖为6.0%,CMC-Na为0.2%(均为质量分数)。     

响应面法优化胡萝卜苹果乳清发酵饮料工艺

实验以胡萝卜、苹果、乳清发酵液为原料,研究乳清发酵饮料制备的工艺条件。采用响应面法对胡萝卜苹果乳清发酵饮料生产的工艺条件进行优化。结果表明,最佳工艺条件为白砂糖6.7%,胡萝卜苹果汁比例2.2∶1(果汁占总量的50%),乳清发酵液添加量38%。最终得到稳定性较好的混合果蔬乳清发酵饮料,感官评价得分为92.5,产品酸甜适中,口感良好,营养丰富,具有浓郁的胡萝卜苹果混合的清香味。     

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