The impact of maturation on concentrations of key odour active compounds which determine the aroma of tequila

Samples of non‐mature and añejo (matured) tequila of the same brand/provenance were analysed using GC–MS and gas chromatography olfactometry (GC‐O)/aroma extract dilution analysis (AEDA) to provide quantitative data on the most odour active compounds that contribute to the aroma of these spirits. Extracts of non‐mature tequila were characterized by 26 odour‐active regions, which included ethyl hexanoate, ethyl octanoate, 2‐phenylethyl acetate, β‐damascenone, isoamyl alcohol and octanoic acid as the most odour‐active compounds (flavour dilution, FD, factor ≥ 6561). In contrast, extracts of the mature spirit showed 36 odour‐active zones, where the compounds with the highest FD factors (6561) were ethyl hexanoate, ethyl octanoate, 2‐phenylethyl acetate, isoamyl alcohol, phenethyl alcohol, guaiacol, 4‐ethyl guaiacol, vanillin, cis/trans whisky lactones, β‐damascenone and octanoic acid. The aromagram of mature tequila was thus differentiated from that of the non‐mature spirit owing to the presence of cask‐extractive compounds and the increased FD factors of certain terpenes, higher alcohols and acetals. This study provides a comprehensive and quantitative understanding of changes in key odourants of tequila as a result of the maturation process and also reveals a further characterization of the likely impact of each compound on overall spirit flavour, in terms of odour activity values. Copyright © 2016 The Institute of Brewing & Distilling     

Batch distillation of spirits: experimental study and simulation of the behaviour of volatile aroma compounds

This paper focuses on the behaviour of volatile compounds during batch distillation of wine or low wine, in traditional Charentais copper stills, heated with a direct open flame at laboratory (600 L) and industrial (2500 L) scale. Sixty‐nine volatile compounds plus ethanol were analysed during the low wine distillation in the 600 L alembic still. Forty‐four were quantified and classified according to their concentration profile in the distillate over time and compared with previous studies. Based on the online recording of volume flow, density and temperature of the distillate with a Coriolis flowmeter, distillation was simulated with ProSim® BatchColumn software. Twenty‐six volatile compounds were taken into account, using the coefficients of the ‘Non‐Random Two Liquids’ model. The concentration profiles of 18 compounds were accurately represented, with slight differences in the maximum concentration for seven species together with a single compound that was poorly represented. The distribution of the volatile compounds in the four distillate fractions (heads, heart, seconds and tails) was well estimated by simulation. Finally, data from wine and low wine distillations in the large‐scale alembic still (2500 L) were correctly simulated, suggesting that it was possible to adjust the simulation parameters with the Coriolis flowmeter recording and represent the concentration profiles of most of the quantifiable volatile compounds. © 2019 The Institute of Brewing & Distilling     

Combining quality and antioxidant attributes in the strawberry: The role of genotype

The nutritional value of fruit has been widely studied and is demanded by consumers, especially for protection against cardiovascular disorder, cancer and other diseases, as well as for general health benefits. These benefits can also be ascribed to the total antioxidant capacity (TAC) of fruit.Fruit nutritional quality can be described by a standard quality parameter and the analyses of nutritional parameters, such as antioxidant capacity (and specific related compounds). In this study, firmness, colour, soluble solids content and titratable acidity were considered as quality parameters and TAC and total phenolic content as nutritional parameters. All these attributes were screened in 20 strawberry genotypes (cultivars and selections) for the selection of new improved genetic material (offspring) originating from different cross combinations, including an F1 Fragaria virginiana spp. glauca among parents.Results indicate that the effect of the genotype on strawberry nutritional quality is stronger than that of the cultivation conditions. However, commercial cultivation did not show a high range of variation of fruit nutritional quality, particularly for the nutritional parameters.The study of offspring originating from different cross combinations showed that fruit nutritional quality can be considered an inheritable trait and that the variability of fruit nutritional quality among commercial cultivars can be improved by breeding.Finally, results demonstrate the role of F. virginiana spp. glauca as an important genetic source of the fruit nutritional quality.     

Grappa quality from the Chianti and Montepulciano areas (Tuscany,Italy): monitoring the leaching of copper from distillation columns

The main aim of this work was to evaluate the leaching of copper in grappa from distillation plant that treats Cabernet and Sangiovese marcs (Montepulciano and Chianti, Tuscany). Copper content (determined by atomic absorption spectrometry, AAS) was 1.05 ± 0.03 mg L^?1 in industrial distillates (Cabernet marc, 82.3% alcohol, v/v), and 3.7 ± 0.2 μg L^?1 in artificial grappa (62.0%, Cabernet) obtained by distilling marc in a laboratory‐scale glassware plant. The artificial grappa distillate was refluxed over copper shavings, and copper content, C_Cu, was analysed in relation to reflux time and wear of the copper bell. The results showed that C_Cu trend was almost linear with increasing alcohol concentration and constant reflux time, and vice versa. The ratios of selected volatile components were not influenced by reflux on the shavings.     

Effect of the operating variables on the extraction and recovery of aroma compounds in an osmotic distillation process coupled to a vacuum membrane distillation system

The coupled operation of osmotic distillation (OD) and vacuum membrane distillation (VMD) for concentration of fruit juices and simultaneous recovery of their aroma compounds was studied. The simulated aqueous fruit juices containing four common aroma compounds were concentrated using osmotic distillation where the feed solution was in contact with a brine solution of CaCl₂, through a hydrophobic macroporous membrane contactor. Aroma compounds absorbed in the extraction brine were extracted using a membrane evaporator under vacuum and collected into a cold trap. This way, both concentration and aroma recovery of fruit juices were achieved simultaneously using two hollow fiber membrane modules. The transfer of the aroma compounds was evaluated by using different operating variables such as hydrodynamic conditions, brine concentration and vacuum pressure. The experiments show that the loss of aroma compounds during the concentration processes can be avoided by means of extraction of the aroma compounds from the brine separately, resulting in an average of 75% recovery in aroma compounds. In general, the process of aroma removal and recovery is faster than the concentration process of the fruit juices by osmotic distillation at a technical and commercial level (higher than 45°Brix). Thus, the simultaneous operation of these two membrane processes can be used to decrease the energy requirements for a given production capacity.     

The role of a low molecular weight glutenin fraction in the cooking quality of durum wheat pasta

Durum wheat glutenin fractions, composed of two low molecular weight proteins DSG-1 and DSG-2 (durum wheat (Triticum durum Desf) sulphurrich glutenin fractions) were extracted from semolina samples using a low concentration of Na tetradecanoate after extracting albumins, globulins and gliadins. DSG proteins have a high? SH plus S? S content. A highly significant correlation was found between the ? SH plus S? S content of this DSG-rich fraction and the cooking quality of pasta (0.63, P <0.01 with firmness and 0.86, P <0.001 with the state of the surface of the cooked pasta) and this seems to be a functional relationship. The use of acetic acid at various molarities showed the presence of high molecular weight glutenin fractions with differing solubility properties. In this respect, differences were found between varieties which are placed in the same group according to the classification of durum wheats based upon the composition of high molecular weight glutenin subunits.     

Batch distillation of grappa: effect of the recycling operation

The effect of the recycling of foreshots and feints during batch distillation of marc has been evaluated. The distillation behaviour of ethanol and congeners was found to be unchanged by the recycle. Instead, the chemical composition of the middle‐cut fraction obtained with recycle of foreshots and feints proved to be richer in ethanol (+4%), higher alcohols (+7%), esters (+13%) and aldehydes (+10%).     

分子蒸馏对沙棘果油品质影响的研究

研究了分子蒸馏法处理沙棘果油,对其中邻苯二甲酸丁酯(DBP)、邻苯二甲酸二乙基己酯(DEHP)和苯并(a)芘的脱除效果以及V_E、α-生育酚、类胡萝卜素、β-胡萝卜素的损失情况进行研究。结果表明:分子蒸馏工艺参数设定为蒸馏温度180℃、刮膜转速300 r/min、系统真空度0.1Pa、进料速率1 m L/min的情况下,蒸馏后的沙棘果油中DBP、DEHP残留量低于国标检出限(均为0.1 mg/kg),显著优于国标限量要求(DBP含量不大于0.3 mg/kg、DEHP含量不大于0.5 mg/kg);苯并(a)芘的残留量为1.56μg/kg,脱除率达到了95.4%,远低于国标限量要求(10μg/kg);酸值(KOH)由14.58 mg/g降到0.52 mg/g;V_E和α-生育酚经分子蒸馏后含量分别为72.91 mg/100 g和67.65 mg/100 g,损失率分别为65.2%和59.2%;类胡萝卜素和β-胡萝卜素的含量分别下降到196.87 mg/100 g和5.25 mg/100 g,损失率分别为1.9%和24.6%。     

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。     

含铜复绿剂对腌渍蕨菜的复绿效果及铜含量变化研究

目的确定腌制蕨菜复绿的最佳工艺条件,并比较复绿前后铜元素含量。方法以醋酸铜复绿剂不同浓度、不同烫漂时间、不同烫漂温度为因素的进行单因素及正交试验,采用色差仪测定复绿前后腌制蕨菜的色泽变化,利用火焰原子吸收分光光度计测定复绿前后腌制蕨菜的铜元素含量。结果醋酸铜复绿剂最佳复绿工艺条件为:烫漂温度95℃,烫漂时间8 min,复绿剂浓度200 mg/L,复绿前腌制蕨菜中铜元素含量为2.08mg/kg,复绿后铜元素含量为4.61 mg/kg。结论醋酸铜复绿剂对腌制蕨菜有复绿效果,最佳复绿工艺条件下蕨菜中铜含量虽符合林业行业限量标准,但含铜复绿剂也不宜使用过多。     

下胶材料对低醇葡萄酒质量的影响

以牛血清蛋白、明胶及皂土为下胶材料,对赤霞珠和佳丽酿为原料酿造的低醇葡萄酒进行下胶实验。结果表明,牛血清蛋白澄清效果最不明显,加入量超过0．05g/L时可使酒中的蛋白质含量和总酚含量增加,吸光值稍微降低；加入明胶和皂土后,葡萄酒的澄清速度较快,蛋白质和总酚含量及吸光值均降低,且随着加入量的增加,降低幅度逐渐增大。三种下胶材料中,皂土的澄清效果最明显,但使酒的口味变淡,颜色变浅,在生产上应慎用；明胶可以优先考虑,因为它的澄清效果较好,颜色变化较小,但易下胶过量,应结合单宁一起使用,效果更佳。     

白茶品质研究进展

主要从白茶非挥发性成分和挥发性成分两方面总结了白茶独特风味形成的原因和影响因素。从鲜叶原料、加工工艺等方面提出提高白茶品质的思路。白茶的高氨基酸、高咖啡碱含量与其制茶品种有关,高黄酮含量则与制茶工艺有关。白茶挥发性组分受到制茶品种和制茶工艺两方面的影响。通过白茶工艺创新,可在一定程度上解决白茶香气低、滋味淡等问题。      

不同蛋壳外观皮蛋的内部品质与铜含量的比较

目的 探究不同蛋壳外观皮蛋内部品质与铜含量区别。方法 使用色彩色差仪、场发射扫描电镜、原子吸收分光光度计和pH计分析不同蛋壳外观皮蛋表面及内质色差、微观差异, 基于皮蛋不同组分铜含量、质构、碱度和载菌量评价皮蛋品质。结果 发现多斑皮蛋(B组)、少斑皮蛋(C组)与无斑皮蛋(A组)、鲜鸭蛋(D组)相比, B、C组蛋壳表面会沉积金属化合物使蛋壳颜色变暗, 甚至是形成小黑点及黑斑, 但是金属化合物主要集中在蛋壳表面及壳膜, 堵孔的同时修补了被碱液腐蚀的蛋壳表面, 阻挡微生物进入, 调节了蛋内碱度, 其可食用部分铜含量也属于安全范围。C组皮蛋形成较好品质的同时, 也拥有更长的保藏期。结论 研究表明适量的硫酸铜使用对皮蛋的品质和可食部分铜的含量有积极影响, 同时也可解除消费者对皮蛋的健康疑虑。     

精炼对菜籽油品质的影响

菜籽油精炼过程是一个发生物理与化学变化的过程,在这一过程中,菜籽油损失了一些天然的微量物质,也引入或产生了多种其他微量物质,而这些微量物质的变化对菜籽油的品质具有决定性影响.对国内6厂家生产的菜籽油进行取样,选取酸值、过氧化值、磷含量、色泽、生育酚含量、植物甾醇含量、反式酸含量这几类对菜籽油品质影响较大的微量物质,对其进行分析测定,以期得到菜籽油精炼各工序中这些微量物质的变化规律,为菜籽油的适度精炼提供依据.     

釜间连接管保温处理对双釜蒸馏樱桃白兰地挥发性物质和蒸馏特性的影响

对双釜蒸馏设备的釜间连接管进行保温改造处理,研究改造前后樱桃原白兰地挥发性香气成分组成和含量的差异及甲醇的含量变化,并核算设备能耗、生产效率、冷却用水量。结果表明,保温改造提高了樱桃白兰地中癸醇、部分乙基酯特别是己酸乙酯和癸酸乙酯的含量;大马酮和香叶醇的含量也升高;糠醛和安息香醛在改造后含量降低;羰基类化合物总量也降低。改造后樱桃原白兰地具有更好的花香、果香和甜香,整体香气强度和纯净度也有所提高。设备在改造后能耗、冷却水用量均下降,蒸馏效率提高。改造对甲醇含量没有显著影响。      

TESTO快速检测法在煎炸油质量监控过程中的应用

生产加工与餐饮企业为降低成本需要合理重复使用煎炸油,为保证煎炸食品的安全性,有必要建立快速有效的检测方法,以便于企业对煎炸油品质进行监控。选用目前生产加工及餐饮企业广泛使用的12种煎炸油为监控对象,包括大豆油、棕榈油、高油酸菜籽油等7种单品油和5种不同组成的调和油,煎炸处理薯条、鸡块和鱼排3种常见快餐食品,试验每12 h取样检测煎炸油中的总极性组分含量(TPC),对比研究柱层析法及TESTO 270快速检测法的结果相关性。试验结果表明,使用快速检测仪检测样品TPC,当TPC20%时,其结果与柱层析法具有显著相关性(Pearson系数为0.744~0.984,P0.01),但当TPC20%时,相关性减弱(Pearson系数为0.553~0.929,P0.01),R~2值为0.149 2~0.863 2。当TPC介于20%至27%之间时,TESTO 270快速检测法的结果有3.6%假阳性,TPC大于27%时,假阴性结果比率为10%。本研究为TESTO 270快速检测法在煎炸油质量监控中的应用提供了参考。     

The role of copper in the manufacture of Finnish Emmental cheese

The effects of added copper in the manufacture of Finnish Emmental cheese were studied. Consequently, cheeses were produced with or without the copper supplement and a facultative heterofermentative strain, Lactobacillus rhamnosus Lc705, which is currently utilized as a protective culture in large-scale manufacture in Finland. Cheeses were examined at 1, 7, 30, 60, and 90 d from the microbiological, chemical, and sensory points of view. Organic acid production was affected by the presence of copper in the cheeses. The addition of copper to cheesemilk increased the level of primary proteolysis and slowed secondary proteolysis as measured by nitrogen content in different extracts after citrate fractionation of cheeses, in pH 4.4-soluble nitrogen and 5% phosphotungstic acid-soluble nitrogen, respectively. The presence of copper appears to positively regulate the sensory characteristics of the cheese produced in our conditions; in particular, consistency was affected significantly. The role of the Lb. rhamnosus Lc705 protective strain has not been shown to have important effects on most of the parameters that influence the final quality of the cheeses. Although the traditional plating systems for revealing bacterial populations during cheese manufacture did not reveal any drastic differences caused by the presence of copper, the results from chemical and sensory analyses suggest that its use plays a significant role in the regulation of bacterial physiological and biochemical activities, which in turn affect the sensory quality of Emmental cheese.     

水蒸气蒸馏法提取八角精油工艺参数的研究

为研究水蒸气蒸馏法提取八角茴香油的最佳工艺参数。以八角茴香果实为原料,选取八角粉碎粒度、浸泡时间、料液比和蒸馏时间进行4因素3水平的正交试验,比较各因素各水平下八角茴香油的提取率,测定茴香油中反式茴香脑含量,计算提取量。研究结果表明影响八角茴香油提取率的主次因素为：蒸馏时间>粉碎粒度>料液比>浸泡时间,且不同粉碎粒度、料液比和蒸馏时间对八角茴香油提取率的影响差异显著（P < 0.05）。影响八角茴香油中反式茴香脑含量的主次因素为：蒸馏时间>粉碎粒度>料液比>浸泡时间,不同的蒸馏时间极显著（P < 0.01）影响八角茴香油中反式茴香脑含量。粉碎粒度和蒸馏时间对八角茴香油提取量的影响差异显著（P < 0.05）,不同的浸泡时间和料液比对八角茴香油提取量无显著影响（P > 0.05）。以提取率和提取量为参数,水蒸气蒸馏法提取八角茴香油的最佳提取条件为: 八角粉碎粒度40目,浸泡32 h,料液比1:10,蒸馏3 h。粉碎粒度、浸泡时间、料液比和蒸馏时间均不同程度地影响八角茴香油的提取率、反式茴香脑含量和提取量。     

Nutrient analysis of the Beef Alternative Merchandising cuts

The objective of this study was to generate raw and cooked nutrient composition data to identify Quality Grade differences in proximate values for eight Beef Alternative Merchandising (BAM) cuts. The data generated will be used to update the nutrient data in the USDA National Nutrient Database for Standard Reference (SR). Beef Rib, Oven-Prepared, Beef Loin, Strip Loin, and Beef Loin, Top Sirloin Butt subprimals were collected from a total of 24 carcasses from four packing plants. The carcasses were a combination of USDA Yield Grades 2 (n = 12) and 3 (n = 12), USDA Quality Grades upper two-thirds Choice (n = 8), low Choice (n = 8), and Select (n = 8), and two genders, steer (n = 16) and heifer (n = 8). After aging, subprimals were fabricated into the BAM cuts, dissected, and nutrient analysis was performed. Sample homogenates from each animal were homogenized and composited for analysis of the following: proximate analysis, long chain and trans-fatty acids, conjugated linoleic acid, total cholesterol, vitamin B-12, and selenium. This study identified seven BAM cuts from all three Quality Grades that qualify for USDA Lean; seven Select cuts that qualify for USDA Extra Lean; and three Select cuts that qualify for the American Heart Association's Heart Healthy Check.     

不同产地雌性中华绒螯蟹感官品质与滋味品质的差异性

该文以上海市松江区的鱼跃养殖产地及崇明区的崇东养殖产地的中华绒螯蟹为研究对象,测定其3个可食部位游离氨基酸和呈味核苷酸的含量,通过计算味道强度值(taste activity value,TAV)及味精当量(equivalent umami concentration,EUC)对这些成分的呈味强度进行评价,结合人工感官...