乳酸菌发酵黄浆水的抗氧化研究

应用鼠李糖乳杆菌和嗜酸乳杆菌发酵豆腐黄浆水,分析了黄浆水和发酵黄浆水还原三价铁、清除DPPH和ABTS+自由基以及螯合二价铁的能力.结果表明,嗜酸乳杆菌发酵黄浆水的还原力最强,显著高于鼠李糖乳杆菌发酵的黄浆水和未发酵的黄浆水;经过发酵的黄浆水清除DPPH和ABTS+自由基的能力明显大于未发酵黄浆水,但是菌种和发酵时间影响不大;螯合二价铁的能力依次为鼠李糖乳杆菌发酵的黄浆水＞嗜酸乳杆菌发酵的黄浆水＞未发酵黄浆水,且延长发酵时间能提高其螯合二价铁的能力.     

碳源对益生菌发酵黄浆水抗氧化和抑菌活性的影响

本文研究了乳糖和蔗糖及其添加量对嗜酸乳杆菌和鼠李糖乳杆菌发酵豆腐黄浆水产酸能力、抗氧化能力和抑菌能力的影响,研究结果表明,添加蔗糖能够提高乳酸菌的产酸能力,其中添加5%的蔗糖发酵24 h时,嗜酸乳杆菌和鼠李糖乳杆菌发酵黄浆水的酸度值分别为95.80 oT和93.68 oT;添加蔗糖也可以增强嗜酸乳杆菌和鼠李糖乳杆菌发酵黄浆水的抗氧化能力,其中添加5%的蔗糖发酵48 h后效果最好,还原力分别为2.57和2.47 mM生育酚/mL样品、清除ABTS自由基分别为37.69和37.98 mM生育酚/mL样品、螯合二价铁离子的能力分别为75.69%和78.70%,菌种之间没有显著性差异;此外,发酵24 h的黄浆水可以抑制金黄色葡萄球菌和大肠杆菌的生长,但对蜡样芽孢杆菌没有抑制效果,其中嗜酸乳杆菌发酵的黄浆水抑菌能力更强,添加1%的蔗糖后发酵黄浆水的抑菌能力稍有增强。     

3种乳酸菌发酵提高黄浆水抗氧化能力的研究

选取植物乳杆菌(Lactobacillus plantarum)、嗜酸乳杆菌(Lactobacillus acidophilus)和清酒乳杆菌(Lactobacillus sakei)对黄浆水进行发酵,以酸度值、活菌数、DPPH自由基清除率、羟自由基清除率、ABTS自由基清除率及铁还原能力为指标,探究3种乳酸菌发酵黄浆水的可行性及对黄浆水抗氧化活性的影响,并测定其总酚和总黄酮含量。结果显示,3种乳酸菌均可在黄浆水中生长产酸,植物乳杆菌与嗜酸乳杆菌的产酸能力与活菌数显著高于清酒乳杆菌,3种菌株组合发酵时黄浆水的DPPH自由基清除率最高,且与发酵过程中总酚含量变化呈显著正相关。发酵后黄浆水提取物对DPPH自由基的清除率IC_(50)值由3.51 mg/m L变为2.43 mg/m L,对羟自由基的清除率IC_(50)值由3.58 mg/mL变为1.82 mg/mL,对ABTS自由基的清除率IC_(50)值由0.90 mg/m L变为0.38 mg/m L,FRAP值由从1.24 mmol/L Fe SO4升高到1.62 mmol/L FeSO_4。     

自然发酵酸浆中一株高产酸菌的分离与鉴定

为明确自然发酵酸浆中的优势产酸菌种并为酸浆豆腐工业化生产奠定基础,以实验室自制黄浆水为培养基,采用平板涂布法,以代谢产酸量和体系pH为指标,从自然发酵酸浆中分离筛选出一株高产酸菌(植物乳杆菌T-02)。该菌株在37 ℃下发酵24 h后pH下降至3.6,总产酸量达35.3 g/L;发酵48 h后pH下降至3.6以下,总产酸量为40.8 g/L,具有较强的产酸能力,可作为酸浆豆腐的纯菌种发酵菌株。采用形态学结合生理生化试验及分子生物学方法鉴定该菌株为植物乳杆菌。     

发酵羊乳产抗氧化肽益生乳杆菌的筛选

研究的主要目的是筛选出能够在发酵羊乳后高产抗氧化肽的乳杆菌菌株。以DPPH自由基清除率、酸度以及p H值作为检测指标,从25株菌株中筛选出目的菌株。结果表明,25株菌株均具有产抗氧化肽能力,以Trolox的抗氧化性为参照,筛选出4株发酵羊乳具有较高DPPH自由基清除率的菌株,分别为植物乳杆菌L60、干酪乳杆菌L49及L61、嗜酸乳杆菌LA5。其发酵羊乳的DPPH自由基清除率分别为69.14%、65.01%、61.34%及56.36%,酸度分别为68、68.8、102.4、72.4 oT,p H值分别为4.80、4.43、4.16、4.42。     

云南石屏豆腐凝乳黄浆水中菌株的分离及产酸能力比较

豆腐黄浆水的凝乳作用与其微生物产酸情况有关,为揭示石屏豆腐凝乳黄浆水凝乳的微生物效果,对其中的微生物进行了分离纯化,并分析了其产酸能力。对石屏豆腐黄浆水样品中的菌株进行分离纯化后得到的四株单菌株:革兰氏阴性短杆菌、极长杆菌,革兰氏阳性杆菌和芽孢杆菌;并以发酵产物pH及酸度为指标,对菌株的产酸能力进行比较,发现混合菌株的产酸能力高于单菌株,凝乳时间短,凝乳效果好,但是所有菌株的凝乳效果都比嗜酸乳杆菌差。该实验为豆腐黄浆水生物转化和再生资源的循环利用提供了参考依据。     

一株耐高温诱变鼠李糖乳杆菌产酸条件优化及其特性分析

利用课题组前期诱变选育的1株耐高温鼠李糖乳杆菌发酵豆腐酸浆,以豆腐黄浆水为培养基,以产酸量、pH值为考察指标,探讨不同发酵温度、发酵时间、乳酸菌接种量及预培养时间对乳酸菌纯种发酵黄浆水产酸情况的影响。在单因素实验结果的基础上,采用正交试验对其发酵条件进行优化,并分析菌株的产酸特性,探讨其代谢通路。结果表明:耐高温鼠李糖乳杆菌在发酵温度37 ℃,发酵时间16 h,接种量5%的条件下发酵黄浆水,其产酸量达43.11 g/L,比诱变前菌株在最佳条件下产酸量提高了9.7%。耐高温乳酸菌纯种发酵有机酸中乳酸、柠檬酸、琥珀酸、丙酮酸、苹果酸、α-酮戊二酸、富马酸含量分别较未诱变菌株纯种发酵的有机酸含量分别提高1.22,1.13,3.14,1.84,4.47,1.18,49.00倍。     

四川传统泡菜中乳酸菌的分离鉴定及抗氧化评估

四川泡菜中含有丰富具有抗氧化能力的乳酸菌,为评估其抗氧化活性,本研究以2,2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基清除能力、1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、亚铁离子螯合能力为指标,探究了从泡菜中分离出来的6株乳酸菌的体外抗氧化活性。结果表明,16S rDNA基因序列鉴定的6株菌均为植物乳杆菌(Lactobacillus plantarum),6株乳酸菌在ABTS~+和DPPH自由基清除、亚铁离子螯合方面均具有一定的作用,其中发酵上清液组菌株SPC-3-1、SPC-1-3、SPC-3-1,完整细胞组菌株SPC-1-1、SPC-3-1、SPC-1-4,无细胞提取物组SPC-3-1、SPC-3-1、SPC-1-3分别在ABTS~+自由基清除能力、DPPH自由基清除能力、亚铁离子螯合能力中最高,分别为89.33%±1.27%、71.88%±0.16%、38.58%±0.85%、15.49%±3.78%、18.65%±1.49%、91.56%±1.73%、14.33%±0.50%、21.06%±1.14%和90.40%±4.58%。在6株植物乳杆菌对ABTS~+和DPPH自由基清除作用中,发酵上清液组的清除率均高于完整细胞组和无细胞提取物组,而在对亚铁离子的螯合能力中,完整细胞组和无细胞提取物组的螯合能力大于发酵上清液组。     

添加瑞士乳杆菌对发酵牦牛乳抗氧化能力的影响

添加瑞士乳杆菌（Lactobacillus helveticus,Lh）与嗜热链球菌-德氏乳杆菌保加利亚亚种发酵剂（Streptococcus thermophilus-Lactobacillus bulgaricus,Y）单独或共培发酵，研究Lh不同接种量对牦牛乳的发酵特性、以及发酵牦牛乳的抗氧化能力与肽含量及蛋白水解活力之间的关系。研究发现，Lh与Y混合发酵能使牦牛乳更快凝乳，凝乳时间为2.67 h；在整个冷藏期间，DPPH自由基清除能力和羟自由基清除能力分别与肽含量呈极显著相关（P<0.01），均表现为先上升后下降的趋势，于第14天达到最大值（P<0.05），其中5%Lh-Y组的DPPH自由基清除能力最强，为93.95%，同时该组样品的羟自由基清除能力最强，为81.83%;Fe2+螯合能力表现为下降趋势，分别与肽含量、蛋白水解活力呈极显著相关（P<0.01）,5%Lh组样品的螯合能力最强；还原能力表现为上升趋势，与蛋白水解活力呈显著相关（P<0.05）,5%Lh-Y组的还原能力最强。结果表明，Lh与Y混合培养能够显著提高发酵牦牛乳样品的抗氧化能力，瑞士乳杆...     

新疆哈萨克酸马奶中功能性乳酸菌株的筛选、鉴定及功能评价

摘 要: 目的 从新疆哈萨克传统发酵酸马奶中筛选和鉴定益生性性乳酸菌,并探究其胃肠道消化耐受性和抗氧化潜力。方法 通过稀释涂布平板法和生理生化鉴定来分离纯化乳酸菌属,利用耐酸性和耐胆盐性筛选出潜在的胃肠道消化耐受性强的候选菌株,采用体外模拟消化、硫酸铁铵比色法和TG试剂盒评估候选菌株的胃肠道存活率、降胆固醇能力和降甘油三酯能力。同时,通过DPPH自由基清除能力、ABTS阳离子自由基清除能力和铁还原能力测试候选菌株的抗氧化潜力,并与德式乳杆菌保加利亚亚种(Lactobacillus delbrueckii subsp. bulgaricus)进行比较分析。最后,采用16S rRNA高通量测序对候选菌株进行精确鉴定。结果 从新疆哈萨克传统发酵酸马奶中分离纯化出96株菌株,40株被鉴定为乳酸菌属。10株候选菌株表现出较高的耐酸性和耐胆盐性,并被鉴定为鼠李糖乳杆菌(Lactobacillus rhamnosus)、植物乳杆菌(Lactobacillus plantarum)、戊糖乳杆菌(Lactobacillus pentosus)和副干酪乳杆菌(Lactobacillus paracasei)。其中,M2菌株（L. rhamnosus）表现出最佳的益生特性,胆固醇和甘油三酯降解率高,模拟胃肠液中存活率高,对DPPH和ABTS自由基的清除能力显著高于德式乳杆菌保加利亚亚种。结论 本研究成功从新疆哈萨克传统发酵酸马奶中筛选鉴定出高耐受性、高抗氧化性的L. rhamnosus M2,为发掘和利用酸马奶中的功能性益生菌提供了理论依据。     

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