贵州茯茶散茶发花条件优化及微生物多样性分析

贵州是我国茶树品种资源最丰富的省份之一,茶园面积大,但经济产值低,夏秋茶浪费严重,品种结构单一。该研究以贵州省安顺市黑毛茶为供试原材料,人工接种茯砖茶“金花”发酵剂,优化散茯茶发花工艺条件,并开展了理化指标变化及真菌多样性研究。通过单因素试验及正交优化试验分析不同因素对黑毛茶散茶发花的影响。结果表明,其最佳发花条件为：含水量30%、温度24 ℃、发酵时间9 d及接种量1:100（m/m）。在此发花条件下,成品散茯茶冠突曲霉孢子数为3×108 CFU/mL,水分、总灰分、茶多酚、游离氨基酸、水浸出物含量分别为3.0%、6.8%、12.0%、2.4%、42.6%。经过上述优化后,茶汤色明亮,金花茂盛,香气纯正,滋味醇和。通过高通量测序技术分析不同发酵时间下散茯茶的真菌多样性。结果表明,发酵3 d后,曲霉属（Aspergillus）相对丰度达到98.8%。该研究优化了贵州散茶发花的工艺条件,对提高茯砖茶品质具有重要意义,为其他茶叶散茶发花工艺提供参考。     

冠突散囊菌接种发酵茯砖茶的初步研究

探讨了冠突散囊菌液体发酵培养条件,并将纯培养冠突散囊菌菌悬液接种于黑茶进行茯砖茶发酵,与市售茯砖茶茶叶浸出液接种于黑茶发酵茯砖茶进行对比试验。实验表明,冠突散囊菌的最佳培养基配方为：NaCl 32g、NH4NO33g、蔗糖20g、MgSO40.5g、K2HPO41g、水1000mL;最佳培养条件为：pH5.8、温度30℃、转速180r/min。试验分别采用冠突散囊菌纯菌液及市售茯砖茶茶叶浸出液分别接种发酵茯砖茶,接种量为5mL、10mL、15mL。发酵中、末期用血球计数板对2组茯砖茶中冠突散囊菌孢子进行计数。经检测,在发酵结束时,接种茶叶浸出液的孢子数只有2.94×104—7.28×104个/g干茶,而接冠突散囊菌菌液的孢子数可达0.313×107—1.71×107个/g干茶。结果表明,使用纯菌液接种发酵茯砖茶可明显提高＂金花＂产量,可为改良传统工艺提供科学依据。     

冠突散囊菌的分离及其液态发酵特性

从茯砖茶中分离冠突散囊菌并研究其液态发酵特性。通过分析不同培养基组分对冠突散囊菌生长情况的影响,得出液态培养基最佳组成:蔗糖6%、黑茶浸提液0.8%。通过正交试验优化发酵条件,最优发酵条件为:初始-pH值为5.5,培养温度为30℃,孢子接种量为1.5%(孢子浓度5.0～6.0×10~8个/mL),摇瓶转数为120 r/min。在最佳培养基和最优发酵条件下摇瓶培养96 h,菌丝体干重可达0.3998 g/L。     

高产阿魏酸酯酶菌株的筛选及其产酶条件优化

通过初筛、复筛从茯砖茶中筛选到了1株产阿魏酸酯酶活力较高的菌株,经个体形态和菌落特征初步鉴定其为冠突散囊菌;以阿魏酸酯酶酶活为衡量指标,选取黑毛茶含水量、接种量、培养温度、培养时间为因子,研究确定筛选出来的冠突散囊菌进行固态发酵黑毛茶的产酶条件。结果表明:黑毛茶固态发酵实验中,黑毛茶含水量26%,接种量1‰,温度30℃条件下培养4d,其酶活力最高可以达到142m U/g。     

人工接种发酵银杏砖茶的研究

为了探索发酵法制作银杏茯砖茶的工艺以及在发酵过程中银杏茯砖茶主要功效成分的变化,通过单因素和正交试验,人工接种冠突散囊菌纯菌种发酵剂进行银杏茯砖茶发酵试验。结果表明,银杏茯砖茶发酵的最佳条件为:银杏茶与黑毛茶比例8:2,含水量35%、二次气蒸后接种、接种量为0.2%;在最佳工艺条件下,随着发酵天数的变化,银杏茯砖茶中银杏酸含量大幅下降,黄酮含量呈先上升后下降的趋势。     

酯化红曲霉菌液态培养条件研究

以红曲霉为原始菌株,经分离筛选获得1株产酯能力较高的红曲霉菌,并对其培养基配方和培养条件进行了研究。试验结果表明,液态发酵培养红曲霉的最佳培养基组成为可溶性淀粉70g/L,黄豆饼粉10g/L,酵母浸膏10g/L,MgSO41g/L,NaNO32 g/L,NaH2PO4 1 g/L;最佳发酵条件为培养基初始pH值为4.5,接种量16%,装液量100mL/300mL,发酵时间为6d,红曲霉的酯化力达0.4678g/100mL。     

酒曲源曲霉的分离及其产蛋白酶条件优化

利用稀释平板法从曲样中分离获得4株曲霉1#、2#、3#和4#,将各菌株分别制米曲后测定酶活力,并通过正交实验及单因素实验确定蛋白酶发酵的培养基和最佳工艺条件。在优化的发酵培养基和发酵条件下(温度、培养时间、培养基起始pH、接种量),产蛋白酶活力分别达到:1#菌11545.7U/g,2#菌8240.4U/g,3#菌9146.0U/g,4#菌4527.7U/g。最后,将活力比较高的三株菌进行Biolog微生物系统鉴定,分别为栖土曲霉(Aspergillus terricola Marchal),寄生曲霉(Aspergillus parasiticus Speare)和杂色曲霉(Aspergillus versicolor)。     

茯砖茶优势菌株分离鉴定及发酵低级绿茶分析

对湖南白沙溪茯砖茶中的优势菌株进行分离、纯化,并通过形态学分析和ITS序列比对进行鉴定.以云南大叶种低级绿茶为原料进行纯菌发酵,分析发酵液主要成分含量的变化.结果表明:从湖南白沙溪茯砖茶中分离得到的4株优势菌株,其中J1被鉴定为谢瓦曲霉(Aspergillus chevalieri);J2、J3和J4均被鉴定为冠突曲霉...     

菌株SFGi-1产赤霉素发酵条件的研究

通过摇瓶培养对菌株SFGi-1产赤霉素的培养基和培养条件进行了优化,确定最佳发酵培养基为液化淀粉100g/L,花生饼粉15g/L,豆粕粉3g/L,硫酸镁0.75g/L,磷酸二氢钾1.0g/L:培养条件为培养温度30℃,接种量5%,250mL摇瓶装液量为35mL,起始DH值为5.5,发酵时间204h.在此条件下,菌株SFGi-1赤霉素发酵最高效价可达到1424mg/L.     

微型茯砖茶发花技术研究

对黑毛茶接种冠突散囊菌,压制为重量为5g左右的圆柱形的茯砖茶再发酵制作微型茯茶。采用单因素试验和正交试验,通过研究茶叶含水量、汽蒸时间、渥堆温度及渥堆时间,筛选出合适的工艺条件,并确定制作微型茯茶的最佳工艺参数。结果表明,影响微型茯茶品质的环境因子依次为含水量〉渥堆温度〉汽蒸时间〉渥堆时间,最优水平为含水量26%、汽蒸...     

高效液相色谱法定量分析不同工艺安化黑茶中功能成分的含量

目的 建立高效液相色谱(High Performance Liquid Chromatography,HPLC)同时测定安化黑茶中没食子酸(gallic acid,GA)、表没食子儿茶素[(-)-epigallocatechin,EGC]、儿茶素[(+)-catechin,C]、表儿茶素[(-)-epicatechin,EC]、表没食子儿茶素没食子酸脂[(-)-epigallocatechin gallate,EGCG]、表儿茶素没食子酸脂[(-)-epicatechin gallate,ECG]、咖啡碱(caffeine,CAF)、可可碱(theobromine,THEOB)、茶碱(theophylline,THEOP)的含量,并比较不同生产工艺的安化黑茶儿茶素类和生物碱类功能成分含量的差异。方法 黑茶样品经90 ℃恒温水浴中浸泡提取后,采用C18色谱柱(4.6 mm×250 mm, 5.0 μm),以乙腈-0.1%磷酸为流动相进行梯度洗脱,流速1.0 mL/min,二极管阵列检测器270 nm 检测。并分析不同生产工艺黑茶中9种功能成分的差异。结果 在选择的分析条件下,黑茶样品中的9种组分获得了理想分离,0.5～100μg/mL范围内线性关系良好(r≥0.9997),加标回收率在81.2%～101.2%之间,相对标准偏差为1.88%～7.61%。不同来源黑毛茶儿茶素类和生物碱类含量成分差异较大,茯砖茶加工过程中儿茶素类成分变化大。结论 该方法操作简单,精密度、稳定性和重现性良好,可用于黑茶中功能成分的定量分析,该研究为安化黑茶的科学拼配、工艺的改进提供了参考依据。     

安化黑茶加工过程中的微生物关系及保健功能 研究进展

近年来随着科技的进步,不论是安化黑毛茶还是成品安化黑茶的生产工艺都在不断创新与突破,产品越来越丰富,品质越来越优质,促进了安化黑茶的极大发展。现代研究表明,安化黑茶品质的形成与加工过程中的微生物作用息息相关,不论是黑毛茶的渥堆过程还是茯砖茶的"发花"工艺,都是以微生物的活动为基础,微生物在利用茶叶中的营养成分供自身生长的同时还分泌多种水解酶类,促进茶叶中内含成分的转化,从而形成安化黑茶优良的品质。由于安化黑茶独特的保健功能,特别是其降脂减肥、改善消化道、防癌抗癌等作用,适应现代需求,深受消费者喜爱。本文综述了安化黑茶中的关键工艺及其创新、微生物相互关系以及其保健功能的研究概况,并对今后安化黑茶中的研究发展方向进行了展望。     

高效液相色谱-高分辨质谱联合CompoundDiscoverer软件分析安化黑茶水溶性成分

目的 建立安化黑茶中水溶性成分的快速分离和确证方法。方法 采用90 ℃热水恒温提取安化黑茶样品中水溶性成分，采用高效液相色谱-高分辨质谱仪对其中的水溶性提取物进行分离测定，利用Compound Discoverer软件分析和匹配实验测定的准确质量数，通过对保留时间、多级质谱、特征碎片离子等特征信息检索，对不同基地的不同工艺的安化黑茶中水溶性化合物的进行初步确证。结果 该法得到了不同基地种植的安化黑毛茶的特征性化合物，分析了安化黑茶中不同加工工艺的黑茶中主要化合物的变化趋势，并首次发现安化黑茶中含有环磷酸腺苷和其他六种未知新化合物。结论 本研究为安化黑茶品质保证和质量控制提供了一种新的技术参考依据，为生产者通过安化黑茶加工工艺来控制成品茶中水溶性成分含量提供了科学的理论依据，为安化黑茶药理活性物质开发提供了新的研究方向。     

安化黑茶水溶性成分高效液相色谱指纹图谱及定量分析

目的:运用高效液相色谱(high performance liquid chromatography,HPLC)法研究湖南安化黑茶指纹图谱,并对安化黑茶的主要成分进行定量分析,为湖南安化黑茶的成分分析与鉴别提供理论依据。方法:以22个安化黑茶样品与4种外省黑茶(云南普洱茶、湖北青砖茶、广西六堡茶、四川土司黑茶)为实验材料,采用梯度洗脱(A相为0.17%乙酸溶液,B相为乙腈),柱温30℃,检测波长280 nm,流速1.0 m L/min,建立安化黑茶HPLC指纹图谱,并进行了相似度评价与主成分分析,确定共有色谱峰。结果:22个安化黑茶样品具有19个共有色谱峰,这些黑茶样品在共有模式下的相似度为0.783~0.958,而广西六堡茶、四川土司黑茶、湖北青砖茶以及云南普洱茶与安化黑茶相似度很低(0.3);定量分析表明,安化黑茶中没食子酸、表没食子儿茶素没食子酸酯的含量明显高于4种外省黑茶,而广西六堡茶中的咖啡因和云南普洱茶中的没食子儿茶素含量明显高于安化黑茶;此外,茯砖素A仅在安化黑茶中检出,可作为安化黑茶的标志性成分。结论:根据所构建的安化黑茶HPLC指纹图谱及找到的标志性成分茯砖素A,可用于安化黑茶的鉴定与评价。     

GC—TOF MS结合化学计量学用于安化黑茶的识别

采用顶空固相微萃取联合气相色谱—飞行时间质谱(GC—TOF MS)对安化黑茶及其它产地黑茶中的挥发性成分进行检测,对41种共有挥发性组分进行定性定量分析。应用化学计量学统计工具对数据进行变量筛选、主成分分析法(PCA)和偏最小二乘判别分析(PLS-DA),筛选出安化黑茶的26个显著性差异香气成分,通过主成分得分投影图直观反映样本间的聚类趋势和分类信息,对安化黑茶与不同产地黑茶样品及其它种类茶叶进行有效区分和识别,找出14个对安化黑茶识别分类起着重要作用的挥发成分。结果表明,基于茶叶中挥发性成分差异的GC—TOF MS分析结合化学计量学统计方法用于安化黑茶识别是可行的。     

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.