四川浓香型原酒中氨基甲酸乙酯含量分析及减控策略的初探

本文通过GC-MS联用技术,对取自四川主要产区的160份浓香型原酒样品中氨基甲酸乙酯含量进行测定。结果显示158份样品检出氨基甲酸乙酯成分,检出率达98.5%。其中有80.5%的原酒样品中氨基甲酸乙酯含量低于加拿大、巴西、法国和日本制定的150μg/L的上限标准。在此基础上分析四川浓香型原酒中氨基甲酸乙酯产生的可能机制,并进一步提出四川浓香型原酒生产过程中氨基甲酸乙酯的减控策略。     

酿造环境对浓香型白酒香味成分乙酸乙酯的影响

通过对酿酒车间窖泥、酒醅、窖池周围土壤、酿造用水进行乙酸菌及金属离子含量检测,并将结果与不同车间浓香型原酒乙酸乙酯含量进行对比,发现酿造环境能够影响浓香型原酒中乙酸乙酯的含量。其环境中乙酸菌、K~+含量与浓香型原酒中乙酸乙酯含量成正比关系,Fe~(3+)含量与浓香型原酒中乙酸乙酯含量成反比关系。     

基于GC-QTOF MS技术的浓香型原酒质量等级相似度研究

为了建立浓香型原酒质量等级标准图谱模型方法,以3个不同质量等级的浓香型原酒为研究对象,通过气相色谱-四极杆飞行时间质谱(GC-QTOF MS)对其进行定性和定量分析。利用平均矢量法和中位数矢量法建立了含有40种特征风味物质的原酒质量等级标准图谱模型并对其相似度及差异性进行评价。结果表明:3个质量等级原酒标准模型之间的相似度均大于89%且都达到了极显著的差异性(双侧Sig0.01),其中建立标准图谱的两种共有模式(平均矢量法和中位数矢量法)和相似度计算的两种算法(相关系数法和向量夹角余弦法)都无差异(双侧Sig0.75)。对于该批次酒样,相似性分析可以用来建立不同质量等级的浓香型原酒标准图谱并能将其进行有效区分。     

基于GC-QTOF MS技术的浓香型白酒原酒质量等级评价

为了探究更加高效科学的原酒质量等级评价方法,本文以浓香型白酒原酒为研究对象,首先对原酒进行感官定级以及通过气相色谱-四极杆飞行时间质谱(GC-QTOF MS)定性和定量分析样品中的43种挥发性风味成分。然后对方法的精密度、重复性和稳定性进行考察,并对测定的结果进行因子分析和回归分析。结果表明:三个质量等级等体积混合酒样中43种挥发性风味成分的相对保留时间和含量的RSD均≤2.98%,该方法具有较好的精密度、重复性和60 h以内的稳定性;10个浓香型白酒原酒通过感官品评可以分为3个等级,通过因子分析剔除掉特征值小于1的主成分中最大特征向量对应的变量,结果保留的23种挥发性风味成分也能够将该批次3个等级原酒进行有效分类,并进一步分析建立了浓香型原酒等级数学评判模型Y(感官品评综合得分)=8.2329F(主成分综合得分)+86.4,R2=0.9801,准确率验证为85.71%,可以对此类浓香型原酒样品的3个等级进行初步评价。     

应用GC-FD和聚类分析比较四川地区白酒原酒与江淮流域白酒原酒

应用直接进样的毛细管色谱法检测了浓香型、清香型和酱香型白酒原酒(60%vol),共获得38种微量成分,其中醇类10种,醛酮类化合物5种,酸类化合物9种,酯类化合物14种.通过比较各种酒中的微量成分发现浓香型、清香型和酱香型白酒原酒的微量成分具有较大的差异.同时也发现,四川SL地区所产的浓香型原酒不同于四川其他3个地区(SG地区、SC地区和SS地区)的原酒,也不同江淮流域所产的原酒,而这3个地区所产的原酒与江淮流域所产的原酒类似.聚类分析的结果与成分分析的结果相同.     

减压蒸馏对浓香型白酒主要风味组分的拆分规律

为探究浓香型白酒主要风味组分在分段冷凝减压蒸馏条件下的馏出规律,采用自主研发的多级连续减压蒸馏装置,分别在不同压力及温度的条件下,对浓香型白酒原酒进行再蒸馏,将浓香型白酒原酒拆分为高沸点、中高沸点、中低沸点、低沸点4个组分,并利用色谱检测各组分中主要风味物质的种类及含量。研究发现,浓香型白酒原酒经减压蒸馏、分段冷凝后,甲醇、乙醛可通过不完全冷凝从原酒中大幅去除,乙醇、主要高级醇及己酸乙酯、乙酸乙酯、丁酸乙酯等有益酯类物质损失较少,且趋于富集在中高沸点、中低沸点组分中,而乳酸、乳酸乙酯等高沸点成分趋于保留在蒸馏釜内的残液中。同时,不同减压蒸馏条件下原酒各段馏出液中风味物质的浓度及比例也不同。结果表明,减压蒸馏可通过改变蒸馏及冷凝条件,针对性地调整浓香型白酒风味成分,这为浓香型白酒原酒风味拆分与重构提供了新的思路及方法。     

不同二次蒸馏方式对浓香型白酒品质影响的研究

我国白酒通常采用甑桶一次蒸馏方式,不进行二次蒸馏。使用壶式蒸馏、常压蒸馏及减压蒸馏3种方式对浓香型原酒进行二次蒸馏,研究蒸馏效率、感官品质及挥发性脂肪酸和四大酯(己酸乙酯、乙酸乙酯、丁酸乙酯和乳酸乙酯)的变化。结果表明,壶式蒸馏效率最高,其次是常压蒸馏、减压蒸馏。使用感官喜好度排序秩次统计,结合Friedman检验与Page检验(α=0.05),发现二次蒸馏酒与原酒存在显著性差异,按喜好度排序依次为减压蒸馏酒、壶式蒸馏酒、常压蒸馏酒和浓香型原酒。二次蒸馏能有效去除原酒的异嗅(如4-甲基苯酚等)。浓香型原酒经二次蒸馏后总酸浓度大幅度下降,而总酯浓度下降差异较大,但酒体仍不失浓香型酒的主体风格。     

固态法五粮浓香型白酒掺杂己酸乙酯的鉴别研究

采用气相色谱-高温氧化-同位素比值质谱联用技术(GC-C-IRMS),以国内市场上广泛存在的针对己酸乙酯掺假的白酒为研究对象,对5种不同等级(优级、一级)、不同年份(2009年、2018年和2019年)的固态法浓香型原酒和市面上最主要的3种关于己酸乙酯掺假的白酒进行了己酸乙酯碳同位素组成测试,结果显示固态法浓香型原酒中己酸乙酯 δ13C值的范围为-15.19‰～-22.14‰,3种掺假白酒中己酸乙酯 δ13C值的范围为-28.34‰～-33.97‰,固态法浓香型原酒中己酸乙酯碳同位素组成相对掺假白酒明显偏重,t检验结果显示sig.(双侧)=0.001<0.05,表明通过GC-C-IRMS技术测试白酒中己酸乙酯碳同位素组成在掺假白酒鉴别方面具有一定的应用价值.     

景芝浓香型白酒降低乙酸乙酯提升感官质量的工艺措施

基于景芝浓香型白酒机械化、自动化和智能化酿造生产条件下,针对新产浓香型原酒乙酸乙酯含量偏高,导致酒体感官质量不佳的技术难题,从出池、入池工艺和摘酒工艺对景芝浓香型白酒酿造工艺进行改进,以期降低浓香型原酒乙酸乙酯含量,提升酒体感官质量。结果表明,与工艺改进前相比,浓香型原酒乙酸乙酯含量降低了32.29%,优级酒及以上产量比例提高了15.16个百分点,酒体感官质量显著提升。     

五粮液原酒中特殊芳香族化合物的空间分布

芳香族化合物是白酒中具有特殊风味的一类化合物,其对白酒酒体的风味贡献度至今仍未厘清。本研究采用了液液微萃取-气质联用技术(LLME-GC/MS)构建了浓香型白酒中9种芳香族化合物的定量方法,研究了不同空间层次(面糟、中层和底层)浓香型原酒中9种芳香族化合物含量和香气活力值(OAV)差异。结果表明,建立的定量方法具有线性好(R20.9971)、检出限和定量限均较低(LOD0.23～3.67μg/L,LOQ 0.77～12.23μg/L),精密度高(RSD2%)等特点。原酒的分析结果可知,9种芳香族化合物中苯乙酸乙酯的含量最高,而苯甲醇的含量最低。对甲酚具有随窖池深度增加而升高的趋势。本研究为浓香型原酒的层次判定提供了数据基础,同时也对"按质并坛"工艺提供了新的理论支持。     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.