基于主成分分析法评价酱香型白酒的不同轮次基酒

为实现酱香型白酒不同轮次基酒的数据化区分和评价,本研究以同一窖池7个轮次的酱香型基酒为对象,使用气相色谱法对样品风味物质进行定量检测,结合主成分分析法进行分析。结果显示,各轮次基酒中总酸含量随轮次数增加而减小,第1轮次酒总酸含量最高,达2.94 g/L,随后一直降低,第6、7轮次酒达到最小值1.51 g/L,总酯含量呈先上升后下降的趋势,由3.57 g/L开始上升,第3轮次总酯含量达到最高值5.14g/L,随后降低至3.10g/L;第1、2轮次酒乙酸、乙酸乙酯和正丙醇含量极高,分别占据14.77%～15.55%、14.16%～22.90%、37.78%～37.98%;主成分分析结果显示,前3个主成分累计贡献率可达到89.30%,综合得分散点图上各轮次酒得到有效区分,第1轮次酒单独占据第1象限,第2轮次酒位于x轴负轴附近,第3～5轮次酒分布较为集中,位于x轴下方、y轴附近,第6、7轮次酒集中于x轴正轴附近,各轮次酒综合评分结果为:4537612。综上所述,利用风味物质的差异性并结合主成分分析法能够准确、快速的对酱香型白酒各轮次基酒进行区别和评价,可以为基酒盘勾、评级提供理论支持。     

酱香型白酒不同轮次基酒的理化特性分析

通过对酱香型白酒不同轮次基酒的理化指标进行测定分析，找出轮次酒成分组成及含量差异，为今后酱香型白酒的综合评价提供一定的指导依据。结果表明：酱香型白酒轮次基酒p H在3.515～3.767之间，电导率在53.2～75.9μs/cm之间，各轮次基酒总酸含量在1.690～4.595 g/L之间，总酯含量在3.325～6.485 g/L，各轮次总酸、总酯变化规律相似，均呈先下降后上升再下降的趋势。根据对各轮次基酒中重金属元素的分析检测，各种重金属元素含量均较低（0.0284～9.849μg/L），其中含量相对较高的元素是锰元素（8.295～32.561μg/L）和铬元素（5.116～49.849μg/L），轮次基酒中重金属元素含量相对较高的是第一轮次基酒和第七轮次基酒。     

基于主成分分析和层次聚类分析的酱香型白酒基酒分类研究

为了区分酱香型白酒不同轮次基酒,对茅台镇49个酱香型白酒基酒样品进行理化指标和感官品评分析,并结合主成分分析（PCA）和层次聚类分析（HCA）进行分类。结果表明,各轮次基酒的总酸、乙酸乙酯、正丙醇含量随着轮次数增加而减少,总酯、乳酸乙酯含量先增后减,醇类、醛类和己酸乙酯含量基本保持稳定。感官品评结果显示,各轮次基酒的风格随着轮次数增加由酯香、粮香、酸、涩向酱香、甜、丰满过渡,最终表现为焦香、苦、丰满。基于理化指标和感官评价结果的层次聚类分析（HCA）和主成分分析（PCA）结果表明,该方法能够有效实现酱香型白酒不同轮次基酒的分类,不同轮次基酒样品可划分为三类：①一、二轮次基酒;②三、四轮次基酒;③五、六、七轮次基酒。     

红曲在牛栏山酒厂二锅头生产中的应用

介绍了红曲的特点及其在我国白酒生产中的应用.以红曲在牛栏山酒厂的应用为例,对红曲基酒与普通基酒的各项指标进行分析.结果表明,红曲基酒总酸、总酯均提高0.05g/L;红曲基酒乙酸乙酯含量提高,乳酸乙酯含量降低.品酒结果表明,红曲基酒的香气和口味得到明显改善.     

机械化酱香型轮次基酒风味结构及特征酯类化合物解析

应用液液萃取结合气相色谱-质谱联用技术对机械化酱香型轮次基酒中风味化合物进行分离、检测。经定性定量结合香气活性值分析,结果表明,机械化酱香型轮次基酒间的风味结构具有显著差异,在酯、醇、酸、醛酮4 类风味物质上的结构差异尤为突出,酯类化合物在酱香型轮次基酒的风味结构中占有重要地位。对酯类进行深入解析后结果表明,乳酸乙酯、乙酸乙酯、己酸乙酯、十六酸乙酯、油酸乙酯、9,12-十八碳二烯酸乙酯、十四酸乙酯、9-十六碳烯酸乙酯、硬脂酸乙酯、13-甲基十四酸乙酯、苯乙酸乙酯、乙酸苯乙酯12 种酯类物质为机械化酱香型轮次基酒的“骨架酯”。月桂酸乙酯、十四酸乙酯对1、2轮次的花香、甜香风味贡献最突出,3-苯丙酸乙酯对1轮次中蜜香及甜香有重要贡献;戊酸乙酯、乙酸戊酯、辛酸乙酯对3、4、5轮次基酒的果香、花香及甜香风味贡献最大,是3、4、5轮次基酒香气协调的特征性酯类物质;除油酸乙酯和十六酸乙酯外,其他酯对6、7轮次基酒的风味贡献均不大。经与传统酿造轮次基酒风味结构比较分析,表明传统与机械化酿造轮次基酒中风味结构具有相似性,特征性酯类成分也具有一定相似度。本研究详细分析机械化酱香型轮次基酒的风味结构及其特征酯类物质,为推进酱香型白酒机械化提供参考依据。     

新高粱与陈高粱对酱香基酒的差异分析

为了揭示新高粱、陈高粱与酱香基酒之间的关系,本研究跟踪了高粱对酿造过程的工艺参数和基酒品质的影响,并对基酒进行了风味成分及感官品评分析。结果表明,新高粱、陈高粱主要成分差异不大,陈高粱新产1轮、2轮次基酒总酸比新高粱略低,陈高粱糟醅在前期轮次堆积发酵时间较新高粱缩短了6～21 h,新高粱、陈高粱糖化堆各层次温度差异不明显,新高粱累计出酒率65.95%,陈高粱累计出酒率66.60%。新高粱、陈高粱新产基酒一共检测到了62种风味物质,醇类、醛类、酮类物质总含量随着轮次增加总体呈下降趋势,酯类、酸类物质总含量随着轮次增加总体呈先升高后下降趋势。经白酒评委综合评定得出：陈高粱新产基酒轮次特征比新高粱更加典型,香气更舒适。     

仁怀大曲酱香轮次基酒质量状况研究

通过对仁怀区域内具有代表性的酒厂进行抽样检测及勾兑品评分析,仁怀大曲酱香各轮次基酒质量状况得到了评估。结果表明,部分轮次基酒质量指标与《仁怀大曲酱香酒技术标准体系》的要求相比,存在偏低问题,其中一轮次基酒酒精度合格率非常低,仅有21.05%;二轮次和五轮次基酒的总酸合格率也较低,分别为44.44%和35.29%;五轮次基酒的总酯合格率较低为52.94%。另外,正丙醇和乙醛分别在一、二轮次基酒中含量总体较高。综合基酒理化及感官检验结果表明,成品酒合格率符合《仁怀大曲酱香酒技术标准体系》及GB/T 26760-2011《酱香型白酒》要求比例,分别为71.2%和98.1%,表明仁怀大曲酱香轮次基酒的品质总体满足勾兑合格成品大曲酱香酒的要求。     

酱香型白酒的轮次酒以及“二次制曲”过程中的风味物质分析

从酱香型白酒发酵过程中采集酒醅和轮次酒样本,检测其中存在的微量成分及其含量,以期总结出酱香型白酒的风味特性。从轮次酒的检测中发现,醇类含量最高的是正丙醇(max=6.76g/L),酯类是以乳酸乙酯(max=2.98g/L)和乙酸乙酯(max=2.85g/L)的相对含量最高,有机酸中含量最高为乙酸(max=1.48g/L),醛类物质以乙醛(max=2.31g/L)含量较高。从酒醅的检测中发现,醇类物质呈现先上升后下降的趋势,依旧是正丙醇(max=7.11g/kg)含量最高,起窖高,下窖低。含量最高为乙酸乙酯(max=3.78g/kg),其次为乳酸乙酯呈现先升后降趋势,且中间轮次达到最高值(max=0.81g/kg)。酸类变化幅度较小,乙酸含量最高(max=1.83g/kg)。醇、酸、酯类物质在窖池发酵的含量高于堆积发酵阶段,说明高温堆积将部分前体物质带到窖内进行分解,并在酒体中高效提取,成为轮次酒中的关键组分。醛类物质整体变化趋势为逐渐上升再下降。总体趋势均表现在第三、四、五轮次酒中维持较高的含量,为优质基酒的产出提供物质前提。     

超长发酵周期对特香型基础酒风味成分影响的研究

研究超长发酵周期对窖池不同糟醅层特香型基础酒总酸含量、总酯含量、风味骨架成分含量及感官风味特征等的影响。结果表明,连续超长发酵周期对特香型基础酒产量有较大影响,第1轮试验组与对照组窖池出酒率无明显差异,第2轮试验窖池出酒率比对照窖池低65.7%。两轮中丢糟总酸含量均为最高,第2轮丢糟总酸含量是第1轮丢糟的1.56倍;两轮中踩糟和丢糟总酯含量均为最高,第2轮踩糟和丢糟总酯含量分别是第1轮的1.29倍和1.26倍;两轮基酒中丢糟中异丁酸、丁酸、异戊酸、戊酸、己酸、乙酸等酸类物质含量显著高于原料糟、踩糟及对照（P＜0.05）;两轮基酒中踩糟和丢糟大部分酯类、醇类及醛类物质含量较高,与对照差异显著（P＜0.05）。感官方面,丢糟和踩糟样品糟味和窖泥味较重;原料糟和对照样品则较为干净,口感更加协调。     

酱香型白酒封窖工艺研究

以传统封窖工艺为对照组,竹席隔离封窖工艺为实验组,通过感官品评、气相色谱分析等方法,对比实验组及对照组生产的窖面基酒产量及质量差异。结果表明,实验组窖面三、四轮次基酒比对照组产量分别提升66.38 kg/窖、19.39 kg/窖,合格率分别提升43.41%、14.28%。与对照组相比,实验组窖面三轮次基酒总酯提升22.76%,丁酸乙酯提升16.56%,四轮次基酒总酯提升11.57%,乳酸乙酯提升22.56%。与对照组相比,实验组三轮次醇甜基酒总酯提升44.20%,乙酸乙酯、丁酸乙酯、乳酸乙酯分别提升12.42%、105.37%、48.72%;四轮次醇甜基酒总酯提升16.84%,丁酸乙酯、乳酸乙酯分别提升17.45%、23.92%。对基酒挥发性风味成分进行偏最小二乘法判别分析（PLS-DA）,可以明确区分实验组与对照组三、四轮次窖面基酒及醇甜基酒。     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.