酒花品种鉴定技术研究——利用顶空CC/MS数据进行颗粒酒花品种鉴定

采用静态顶空-气相色谱-质谱法(HS-GC/MS)对酒花油的成分进行了分析研究,共分离和鉴定了74种化合物,它们属于萜烯类碳氢化合物、含氧化合物和含硫化合物。以酒花挥发性成分为基础对酒花进行聚类分析,既能寻找酒花的替代品也能够进行酒花品种的鉴定。     

酒花品种鉴定技术研究--利用顶空GC/MS数据进行颗粒酒花品种鉴定

采用静态顶空-气相色谱-质谱法(HS-GC／MS)对酒花油的成分进行了分析研究。共分离和鉴定了74种化合物，它们属于萜烯类碳氢化合物、含氧化合物和含硫化合物。以酒花挥发性成分为基础对酒花进行聚类分析，既能寻找酒花的替代品也能够进行酒花品种的鉴定。     

葡萄柚精油的气相色谱-质谱分析

采用水蒸汽蒸馏法提取葡萄柚精油,经气相色谱和质谱联机分析,同时依据各成分的保留指数,鉴定出63种挥发性物质,其中有21种碳氢化合物,32种含氧化合物.在碳氢化合物中以柠檬烯、γ-萜品烯为主要成分;而在含氧化合物中主要是沉香醇、α-萜品醇、百里酚以及一些脂肪族醛.     

酸桔果皮油挥发性成分的研究

用溶剂萃取法从酸桔果皮提取精油,并用硅胶柱将精油分成碳氢化合物和含氧化合物两大部分。利用气相色谱和质谱联用系统测定了酸桔果皮油的挥发性成分,并依据各成分的保留指数,鉴定出68种挥发性成分,其中有23种碳氢化合物、16种醇类物质、16种醛类物质、2种酯类物质、2种酚类物质、5种醚类物质和4种酮类物质。     

气相色谱法分析酒花油的主要香气物质研究

建立了用气相色谱法测定酒花油中香叶烯、里那醇、石竹烯、法尼烯和律草烯含量的方法，并对4种酒花油样品进行了捡测：采用水蒸气回流提取法进行样品前处理．以十四烷作为内标物，色谱条件为：载气流速2.0ml/min、柱温为程序升温，100℃（Omin）-10℃/min-160℃（Omin）-30℃/min-210℃（5min），分流比25：1，进样量0．5℃L；分析时间短．12分钟内即可完成。内标法定量测得相对标准偏差为0．0120％～1．0707％，回收率在95．18％～102．25％之间，具有操作简便快捷、精密度好、准确度高的特点。检测结果表明，不同品种酒花油样品在主要香气物质上有较大差异，可以据此对酒花油及相应酒花的品质进行监控。     

紫薯酸奶和普通酸奶挥发性风味物质差异性研究

本文采用顶空固相微萃取法提取紫薯酸奶和普通酸奶中的挥发性风味成分,用气相色谱-质谱仪进行测定,结合NISTLibrary数据库自动检索技术对有机风味化合物进行鉴定。在相同的检测条件下,分别检出紫薯酸奶和普通酸奶中有75和46种挥发性成分。乙酸、乙醛、双乙酰、丁位壬内酯等特征性风味物质在两种酸奶中均检测出来。普通酸奶含芳香杂环化合物和萜烯类各3种和1种,分别占1.42%和0.77%。而紫薯酸奶中含芳香杂环化合物和萜烯类达6种和5种,各占2.33%和5.96%。橙花醇、愈创木酚、香草醛等只在紫薯酸奶发现,尤其是橙花醇占4.77%。这些特色风味成分的生成可能是发酵过程中紫薯本身成分参与了酸奶的发酵过程,生成了多种风味物质,导致紫薯酸奶中的挥发性成分较多,而且有效的风味物质也增加,赋予了紫薯酸奶柠檬样的果香。     

酒花与酒花制品抗氧化特性的研究

本文采用DPPH（二苯代苦味酰肼自由基）方法来测定酒花与酒花制品的抗氧化特性。抗氧化活性通过反应环境的吸光度下降速率与相对百分比表示。捷克酒花与外国酒花制品的抗氧化活性不同,最高是Saaz和Spalter酒花,范围在70%～80%之间,而大部分酒花制品的抗氧化特性在40%～60%之间。酒花的一部分抗氧化活性在其干燥过程中直接损失掉,但损失率小于5%。酒花干燥过程会使多酚化合物含量下降。长期的储存也会使酒花的抗氧化活性下降,颗粒酒花真空铝铂包装时温度对抗氧化活性没有大的影响。     

白柠檬果皮油特征香气成分的评价

用客观方法 ,评价了白柠檬果皮油的特征香气成分。用溶剂萃取法提取白柠檬果皮的精油 ,并用硅胶柱将精油分成碳氢化合物和含氧化合物两大部分 ,由于含氧化合物部分具有果皮油的特征香气 ,利用各成分的香气值对该部分进行了评价 ,明确了香叶醛、橙花醛、沉香醇以及一些脂肪族醛等 2 5种成分对白柠檬果皮油香气起着重要作用。用这些成分按着在果皮油中的含量比调配成的混合液具有白柠檬果皮的香气。由此可知 ,利用香气成分的香气值 ,能够筛选出对食品的香气起重要作用的成分。     

珊瑚姜油的抗氧化性

采用超临界CO2萃取珊瑚姜得到珊瑚姜油,添加到在烘箱强化保存条件下(60～65℃)的浓缩鱼油中,测定鱼油的过氧化值(POV),考察珊瑚姜油对浓缩鱼油的抗氧化能力;并用气相色谱-质谱联用仪(GC-MS)对珊瑚姜油进行分析,从化学组成探讨珊瑚姜油与BHT和VE对鱼油的抗氧化机理差异。结果表明：珊瑚姜油抗氧化效果优于BHT及VE,是一种良好的天然抗氧化剂,珊瑚姜油添加量为0.03%时对鱼油很好的保护作用;GC-MS方法鉴定出珊瑚姜油有44种成分：单萜类化合物13种,占25.12%;含氧单萜类化合物16种,占26.43%;倍半萜类化合物9种,占8.82%;含氧倍半萜、苯系衍生物及其他6种,占39.63%。     

酸桔果皮油的特征香气成分

为评价酸桔果皮的特征香气成分,先用同时蒸馏与萃取法(SDE)提取酸桔果皮的精油,并用硅胶柱将精油分成碳氢化合物和含氧化合物两大部分.含氧化合物部分具有果皮油的特征香气,用GC/MS对该部分进行了分析,鉴定出56种含氧化合物成分,然后用GC-Sniffing方法评价了酸桔果皮油的特征香气成分,明确了顺式氧化沉香醇、沉香醇、顺式氧化柠烯、香茅醛、香茅醇、香芹酮以及一些脂肪族醛等12种成分对酸桔果皮的香气影响.用这些成分按适当比调配成的混合液基本上能够代表原果皮的香气.     

Changes in the composition of hop secondary metabolites induced by high hydrostatic pressure

Hops contain large amounts of secondary metabolites, many of which have notable bioactive and sensory characteristics. Many of these properties are affected by the processing of raw hops into products. We studied the influence of high‐pressure processing (HPP) on the content and composition of secondary metabolites in hop homogenates prepared from fresh green cones of several Czech hop varieties. Homogenates contained more hop oils (27% on average) compared to dried hops. The composition of essential oils in homogenates after HPP showed a decrease in fatty acid methyl and thioesters fractions (80 and 100% respectively). Conversely, the number of other bioactive compounds from the group of resins and prenylflavonoids that remained in HPP homogenates was retained to a greater extent than in the dried hops. Low temperatures and an oxygen‐free atmosphere were effective conditions for the preservation of raw hops and hop products. Copyright © 2018 The Institute of Brewing & Distilling     

Comparative Gas Chromatographic–Mass Spectrometric Evaluation of Hop (Humulus lupulus L.) Essential Oils and Extracts Obtained Using Different Sample Preparation Methods

The main aim of investigations was to identify chemotypes and determine differences between some domestic hop varieties and wild hops, which were collected from some regions of Lithuania and cultivated at the same edafoclimatic conditions in hops collection of Kaunas Botanical Garden of Vytautas Magnus University. One of objectives was to compare essential oils of hops (2 years harvest) by the evaluation of volatiles content. Among the main components of hop essential oils monoterpenes (β-myrcene) and sesquiterpenes (α-humulene and β-caryophyllene) were determined using gas chromatography coupled with mass spectrometry (GC-MS). Retention parameters (t _R, calculated retention index, and Kovats retention index) and m/z value of molecular ion for selected compounds from hop essential oils were determined. Samples were prepared by applying solid phase microextraction (SPME), supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE). The steam distillation was used to obtain hop essential oils. The chemometric comparison of domestic and wild hops based on GC-MS analysis data was carried out. The obtained statistical results allow us to classify the investigated wild forms and domestic varieties of hops according to the similarities of their chemotypes. The concentration of β-myrcene, α-humulene in hop essential oils obtained from cones 2 years harvests is much higher than other volatile organic compounds (15.2–23.7 % in total contribution). In analysed essential oils β-farnesene is a constituent in higher quantity of hop essential oils obtained from cones from second time harvest than from cones from first harvest. This can be explained by the year-to-year vegetation conditions difference.     

PREPARATION OF HOP EXTRACTS RICH IN PARTICULAR CONSTITUENTS*

When a column containing powdered hops is extracted with liquid carbon dioxide, chromatographic separation of hop components occurs. They are extracted in the order essential oils, β-acids, α-acids; and the separation is enhanced when finely milled hops are extracted. Early fractions (～0·5 hour) contain a high proportion of the available essential oils when hops are extracted at ?20°C and such extracts are suitable as a replacement for dry hops. Fractions can be obtained from extractions at ～7°C which are rich in α-acids and contain low levels of β-acids. Small amounts of fats and waxes are normally present in fractions collected towards the end of a run when seeded hops are extracted.     

PREPARATION OF OIL RICH HOP EXTRACTS AND THEIR ADDITION TO BEER ON THE PILOT-SCALE USING LIQUID CARBON DIOXIDE*

The introduction of carbon dioxide hop extracts dissolved in liquid carbon dioxide to green beer during transfer from fermentation vessel to cold conditioning tank results in a sound dry hop flavour in the finished product. A system has been developed for injecting a solution of extract into a beer main. Extracts which are rich in hop oils are particularly suitable for imparting hop character to beer and a liquid-liquid countercurrent procedure is described for producing extract fractions containing enhanced levels of essential oil.     

Humulus lupulus – a story that begs to be told. A review

The hop cones of the female plant of the common hop species Humulus lupulus L. are grown almost exclusively for the brewing industry. Only the cones of the female plants are able to secrete the fine yellow resinous powder (i.e. lupulin glands). It is in these lupulin glands that the main brewing principles of hops, the resins and essential oils, are synthesized and accumulated. Hops are of interest to the brewer since they impart the typical bitter taste and aroma to beer and are responsible for the perceived hop character. In addition to the comfortable bitterness and the refreshing hoppy aroma delivered by hops, the hop acids also contribute to the overall microbial stability of beer. Another benefit of the hop resins is that they help enhance and stabilize beer foam and promote foam lacing. In an attempt to understand these contributions, the very complex nature of the chemical composition of hops is reviewed. First, a general overview of the hop chemistry and nomenclature is presented. Then, the different hop resins found in the lupulin glands of the hop cones are discussed in detail. The major hop bitter acids (α‐ and β‐acids) and the latest findings on the absolute configuration of the cis and trans iso‐α‐acids are discussed. Special attention is given to the hard resins; the known δ‐resin is reviewed and the ε‐resin is introduced. Recent data on the bittering potential and the antimicrobial properties of both hard resin fractions are disclosed. Attention is also given to the numerous essential oil constituents as well as their contributions to beer aroma. In addition to the aroma contribution of the well‐known essential oil compounds, a number of recently identified sulfur compounds and their impact on beer aroma are reviewed. The hop polyphenols and their potential health benefits are also addressed. Subsequently, the importance of hops in brewing is examined and the contributions of hops to beer quality are explained. Finally, the beer and hop market of the last century, as well as the new trends in brewing, are discussed in detail. Hop research is an ever growing field of central importance to the brewing industry, even in areas that are not traditionally associated with hops and brewing. This article attempts to give a general overview of the different areas of hop research while assessing the latest advances in hop science and their impact on brewing. Copyright © 2014 The Institute of Brewing & Distilling     

2种艾叶酚类化合物与挥发油成分比较

为研究艾叶化学成分与其产地之间关系,分别以产自河南南阳和新疆的艾叶为实验材料,对比研究其酚类化合物和挥发油的组成。以体积分数60%乙醇溶液为溶剂超声提取酚类化合物,高效液相色谱法结合标样检测其组成;同时蒸馏萃取结合气相色谱-质谱联用检测挥发油的化学成分。结果表明,河南南阳和新疆艾叶挥发油得率分别为2.644%、0.805%;河南南阳、新疆艾叶分别检测出标准品中的19种和14种酚类化合物,总含量达13.43 mg/g和9.75 mg/g;挥发油中分别鉴定出29种和12种化合物,占挥发油总量的80.24%和71.22%。河南南阳艾叶比新疆艾叶含有更加丰富的酚类化合物和挥发油。     

Number and size of lupulin glands,glandular trichomes of hop (Humulus lupulus L.), play a key role in contents of bitter acids and polyphenols in hop cone

Hop (Humulus lupulus L.) inflorescence, commonly known as ‘hop cone’, is valuable for contents of bitter acids, essential oils and polyphenols, used in brewing industry and biomedical application. These compounds are predominantly formed in glandular trichomes, known as ‘lupulin glands’. In this study, we investigated chemical and morphological characteristics of lupulin glands by microscopy and HPLC analyses. Even though no significant correlations were found between lupulin glands and hop cones for contents of alpha and beta bitter acids, polyphenols, all ratios between individual metabolites (alpha/beta acids, X/alpha acids, X/DMX) were highly and significantly correlated. The average number of lupulin glands on bract/bracteole ranged from 115 to 713 with 28.5% of variability. Linear regression analyses confirmed that total volume of lupulin glands and total lupulin glands area on bract/bracteole surface highly correlated with contents of bitter acids and polyphenols in hop cone. Therefore, lupulin glands are unique and exclusive organs responsible for contents of bitter acids and polyphenols in hop cone.     

DIFFERENCES IN UTILISATION OF THE ESSENTIAL OIL OF HOPS DURING THE PRODUCTION OF DRY-HOPPED AND LATE-HOPPED BEERS

Late-hopped and dry-hopped beers were prepared and their lipophilic constituents extracted using Amberlite XAD-2 resin. Examination of the volatile constituents by GC-MS confirmed that most of the hop oil added towards the end of wort boiling is lost by evaporation. Part of the material which survives boiling is chemically transformed by yeast during fermentation. Dry-hopped beer contained compounds more representative of the original hop oil than did the corresponding late-hopped beer. A liquid carbon dioxide extract of hops, rich in essential oil, has been fractionated by column chromatography on alumina-silica giving preparations which simulate either late-hop or dry-hop character.     

不同发育期椪柑精油对意大利青霉和指状青霉的抑制作用

对不同发育期（7、8、9和10月）的椪柑（CitrusreticulataBlanco）果皮精油进行GC-MS分析,共鉴定出柠檬烯（47.28%～58.40%）、γ-松油烯（8.27%～13.23%）、β-芳樟醇（3.48%～7.86%）、β-月桂烯（6.24%～7.50%）、α-蒎烯（5.07%～6.05%）、β-蒎烯（2.30%～3.45%）和辛醛（2.04%～2.48%）等50种萜烯类化合物。椪柑果皮精油及其所含的6种潜在抑菌组分（柠檬醛、辛醛、壬醛、癸醛、β-芳樟醇和α-松油醇）的体外抑菌实验结果表明:不同发育期椪柑果皮精油对意大利青霉（Penicillium italicum）的抑制作用要强于指状青霉（P.digitatum）;潜在抑菌组分中柠檬醛和辛醛对意大利青霉的抑菌效果最好,壬醛和辛醛对指状青霉的抑菌效果最好。柠檬醛和辛醛对意大利青霉的最小抑菌浓度（MIC）、壬醛和辛醛对指状青霉的MIC均为0.50μL/mL;β-芳樟醇和α-松油醇对意大利青霉和指状青霉的MIC均为2.00μL/mL。