干酪乳杆菌对柑橘汁发酵的工艺研究

研究了干酪乳杆菌发酵柑橘汁的发酵过程.接入柑橘汁后的0～10h内干酪乳杆菌处于迟滞期;第10h开始发酵进入对数期,并在第52h结束,发酵终点的活菌数为1.31×109 cfu/mL;发酵液pH值从起点的6.11降至终点的3.69;发酵液最高总酸达到1.48 g/100mL.进一步研究了干酪乳杆菌营养源的优化,结果表明添...     

甜豆瓣发酵过程中关键控制指标研究

研究甜豆瓣自然发酵过程中总酸、氨基酸态氮、发酵液pH值、发酵液盐分、水分含量的变化。豆瓣胚氨基酸态氮含量由0.37g/100g上升到(0.73±0.03)g/100g,豆瓣胚总酸含量由0.47g/100g上升到(1.8±0.1)g/100g,发酵液pH值开始时为6～7,发酵过程中随着总酸波动,发酵成熟后pH值降低至4.3±0.1。将检测的理化指标与感官评分进行相关性分析,确定判断甜豆瓣发酵成熟的关键指标分别是氨基酸态氮、总酸、发酵液pH值。     

乳酸菌在大豆黄浆水中发酵条件的优化

以乳酸乳球菌乳亚种为发酵菌株,大豆黄浆水为培养基质,产酸量、pH值为考察指标,探讨不同发酵温度、发酵时间、种子液接种量、葡萄糖添加量对乳酸乳球菌乳亚种在黄浆水中发酵产酸的影响。在单因素试验的基础上,采用均匀设计法对其发酵条件进行优化,并对产酸量进行二次多项式逐步回归分析。结果表明,乳酸乳球菌乳亚种在黄浆水中最适发酵条件为发酵温度35℃、种子液接种量9%(V/V)、发酵时间68h、葡萄糖添加量5%(m/V)、初始pH 6.2,该条件下产酸量达0.791 3g/100mL,pH为3.40。     

高产γ-氨基丁酸富锌乳酸菌的分批及补料发酵研究

以短乳杆菌BS2为研究对象,根据已优化的培养条件,使用15L发酵罐进行分批及分批补料发酵实验,在严格控制条件下观察γ-氨基丁酸(GABA)的生物转化过程,克服摇瓶发酵的不足。采用初始pH值为5,发酵期间不控制pH值的条件下进行分批发酵;而后通过发酵期间控制pH值为5的条件下再次进行分批发酵,GABA含量得到有效提高,而谷氨酸钠和葡萄糖分别在32h和44h基本耗尽;然后采用初始pH值为5,发酵期间控制pH值不变的条件下分别在32h补入谷氨酸钠,44h补入葡萄糖,其中,补加550g/L葡萄糖200mL,630g/L谷氨酸钠200mL。补料发酵时,两者流加速度均为11.1mL/min,流加18min。流加结束后培养基中葡萄糖和谷氨酸钠含量达到18g/L以上,基本达到在初始发酵时的质量浓度,而谷氨酸钠在56h基本耗尽,GABA产量达到22.5g/L,最后在56h第2次补加谷氨酸钠,操作同上,GABA产量在104h达到33g/L以上。     

冷却肉天然复合保鲜剂配比的优化

根据中心复合设计原理,在琼脂扩散法得出3 种天然保鲜剂最小抑菌浓度基础上,运用Minitab14 数据统计分析软件,采用四因素二水平中心复合响应曲面分析法,确定保鲜剂的最佳配比为Nisin 0.2773g/100mL、溶菌酶0.46g/100mL、乳铁蛋白0.604g/100mL、pH5.16。pH 值与乳铁蛋白、pH 值与溶菌酶、pH 值与Nisin、乳铁蛋白与溶菌酶以及溶菌酶与Nisin 之间均存在显著的交互作用(P＜ 0.01),而乳铁蛋白与Nisin 交互作用不显著(P＞0.05)。单因素对细菌总数影响的大小次序为Nisin ＞溶菌酶＞ pH 值＞乳铁蛋白。     

混合菌种发酵板鸭工艺优化及品质分析

以三穗麻鸭为原料,植物乳杆菌和戊糖片球菌作为发酵剂,通过单因素和正交实验,以板鸭的感官评分和pH值作为评价标准,确定其最佳工艺配方,测定其理化指标,并对其品质特性进行研究。结果表明:最佳工艺条件为菌种接种量3.0%、植物乳杆菌-戊糖片球菌接种比例1∶2、发酵温度30℃,发酵时间20 h。此工艺下制得的发酵板鸭水分含量为35.50±2.25%,pH值为5.58±0.09,L*为36.85±2.45,a*为14.55±2.45,b*为7.70±0.80,过氧化值为0.08±0.00 g/100 g,挥发性盐基氮(TVB-N)为19.36±0.01 mg/100 g。与对照组对比,实验组的硬度、弹性、内聚性及咀嚼性更好,此条件下生产的板鸭颜色均匀,风味浓郁,品质得到提高。     

发酵火麻仁乳的工艺优化及抗氧化活性变化

将熟化火麻仁乳作为原料,以乳酸菌复配比例、菌种添加量、发酵温度与发酵时间为自变量,活菌数、酸度、感官评价为评价指标,采用模糊综合评价法通过单因素试验及响应面试验确定火麻仁发酵乳最佳生产工艺配方。实验表明:当保加利亚乳杆菌:嗜热链球菌:干酪乳杆菌:嗜酸链球菌复配比例为2:2:1:1.78、接种量为6.21%、发酵温度为39.42℃、发酵时间为7.12 h条件下时,模糊综合评价值最高,为0.927分,其活菌数、酸度及感官评分分别为1.9×10~8 CFU/m L、78 ~oT和8.74分。发酵后火麻仁乳的总糖、总固形物含量分别为69.29 mg/mL、6.08±0.22 g/100 g,与发酵前相比含量显著降低(p0.05),总酸、总酚和总黄酮含量分别为7.99±0.34mg/m L、28.04±0.82 mg GAE/100 mL、27.11±1.34 mg GAE/100 mL,含量均比发酵前显著提高(p0.05)。抗氧化实验表明,当DPPH自由基清除率、ABTS~+自由基清除率为50%时,发酵后火麻仁乳浓度分别为26.09 mg/mL、7.22±0.13 mg/mL,与0.25 mg/mL和0.13mg/mL生育酚相当,抗氧化活性得到了显著提高(p0.05)。     

零乳糖乳酸菌发酵菌种的筛选及应用研究

从130份西藏地区牧民自制发酵乳制品中分离得到392株乳酸菌,并筛选得到一株能够大量且快速消耗乳糖乳杆菌,经16S rDNA测序后,鉴定为德式乳杆菌保加利亚亚种（Lactobacillus delbrueckii subsp. bulgaricus）,命名为WHH3887。该菌株在乳中具有良好的发酵性能,37℃发酵12 h可产生乳酸12.689±0.05 g/L,并形成良好的发酵乳组织状态和风味,同时可将乳糖含量显著降低至1.41±0.02 g/100g。对该菌株的高密度培养工艺进行单因素优化,确定了最适碳源为乳糖30.0 g/L,最适氮源为牛骨蛋白胨30.0 g/L、牛肉浸粉10.0 g/L、胰蛋白胨15.0 g/L,生长因子为番茄汁1.5 g/L和精氨酸0.1 g/L,最适pH值为5.5,最适温度为40℃。此条件下,发酵液活菌数最高可达到1.89×109 CFU/mL,冷冻干燥后菌粉活菌数最高可达到1.93×1011 CFU/g。以冻干菌粉为直投式发酵剂自制的发酵乳具有良好的感官品质,发酵10 h,乳糖含量为1.83 g/100g,发酵24 h,乳糖含量为0.44 g/100g,分...     

清涧红枣乳酸菌发酵饮料工艺优化

以清涧红枣为原料,提取红枣枣清汁。通过选择干酪乳杆菌、植物乳杆菌和鼠李糖乳杆菌3种乳酸菌进行单独及复配发酵,探索发酵时间、发酵菌种、接菌量及枣清汁初始可溶性固形物含量对发酵饮料pH及感官评价影响,并通过正交试验优化发酵工艺。结果表明,红枣枣清汁以干酪乳杆菌:植物乳杆菌:鼠李糖乳杆菌=6:1:1 (m/m)复配发酵为宜,接菌量为0.01%,在初始可溶性固形物含量13.5%,37 ℃发酵48 h,pH为3.61,乳酸菌活菌数≥1.5×108 CFU/mL,还原糖含量为10.46 g/100 g,总酸含量为8.99 g/kg,符合QB/T 5356-2018果蔬发酵汁标准;环磷酸腺苷含量为21.4 μg/mL,较好的保留了发酵前枣清汁中含有的环磷酸腺苷。本文制备出一款营养丰富、风味俱佳地清涧红枣乳酸菌发酵饮料。     

4种乳酸菌甜玉米乳清蛋白饮料发酵过程主要品质指标分析及感官评价

为了筛选出适合于发酵甜玉米乳清蛋白饮料的最佳菌种,对常用于发酵乳和谷物类饮料的4种可食用乳酸杆菌--植物乳杆菌、鼠李糖乳杆菌、干酪乳杆菌、嗜酸乳杆菌在甜玉米乳清蛋白饮料中的发酵特性进行了研究。将4种不同菌种接种到甜玉米乳清蛋白混合液中,37℃下发酵12 h,每隔2 h监测发酵过程中pH值、可滴定酸度、还原糖消耗、可溶性蛋白及游离氨基氮这几项主要品质指标的变化情况,并结合感官评价来分析这4种菌株发酵甜玉米乳清蛋白饮料的特性。结果表明:同其他3种乳酸菌相比,植物乳杆菌甜玉米乳清蛋白饮料发酵时间最短,8 h完成发酵过程,pH下降速率最快,达0.31/h,后酸化能力弱。发酵终点酸度与适口性高度契合,此时pH为4.30、可溶性蛋白含量为5.75 mg/g,游离氨基氮含量为4.62 ug/mL,感官评价分值最高。     

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