Effect of light and temperature on 3-alkyl-2-methoxypyrazine concentration and other impact odourants of Riesling and Cabernet Franc wine during bottle ageing

3-Alkyl-2-methoxypyrazines (MPs) are grape- and insect-derived odour-active compounds responsible for green and vegetative perceptions in wine, and at elevated concentrations are detrimental to wine quality. We examined the influence of light and temperature during cellaring on MPs and other impact odourants. Riesling and Cabernet Franc wines were supplemented with 30 ng/L of each of 3-isopropyl-2-methoxypyrazine (IPMP), 3-s-butyl-2-methoxypyrazine (SBMP) and 3-isobutyl-2-methoxypyrazine (IBMP), and stored under one of the following conditions: (i) at ambient temperature (22 °C) under fluorescent lighting, (ii) in the dark at ambient temperature, or (iii) in the dark at cellar temperature (12 °C). Additionally, for the light condition, wine was stored in clear, green or amber bottles.     

酱油中香气成份的试验研究

本文就酱油的香气成份进行了试验研究。在发酵过程中添加酵母和在成品酱油中添加酵母风味强化剂进行了试验研究和比较。     

OXIDATIVE DEGRADATION OF ISOHUMULONES IN RELATION TO FLAVOUR STABILITY OF BEER

Isohumulones undergo oxidative degradation in bottled beer during shelf storage to give volatile compounds including 2-alkanones with chain lengths of C₃ to C₁₁, alkanals with chain lengths of C₂ to C₁₀ 2-alkenals of C₄ to C₇ or more and 2,4-alkadienals of C₆ to C₇. Since some resultant aldehydes are involved in the formation of stale aldehydes, very high levels of isohumulones in beer may cause considerable staling of beer flavour. Isohumulones were decomposed to these carbonyl compounds more easily than their derivatives, such as di- or tetrahydroisohumulones and humulinic acids, because the double bond or carbonyl group of the isohexenoyl side chain of the isohumulone molecule is involved in this degradation. This oxidation of isohumulones was greatly suppressed by addition of 300 ppm of sodium ascorbate or 40 ppm of ferrous ion.     

CHEMICAL CHARACTERIZATION OF DIFFERENCES BETWEEN ALES AND LAGERS

The chemical identification of the substances responsible for differences between ales and lagers has been investigated, using new as well as established techniques. The two types of beer are broadly similar in composition, but lagers are characterized particularly by higher levels of certain sulphur compounds, and ales by higher levels of certain heterocyclic compounds. Several compounds have been identified for the first time as beer components.     

Compositions,flavour and antiradical properties of products from subcritical water treatment of raw Isada krill

Comparative analysis of subcritical water (SCW) treatment and ambient pressure boiling one of raw Isada krill was performed for the nutritive, flavour and antiradical properties of krill extracts and residues as well as the molecular mass and odour intensity of the extract. SCW treatment was performed for 10 min in a batch‐type vessel in the temperature range of 100–240 °C, using a 1:1 weight ratio of raw krill to water. Higher protein and lipid contents were obtained by SCW treatment relative to boiling. The lipid content of the SCW extracts increased with increasing treatment temperature. Protein was the main component in these extracts, and the highest protein content was achieved by SCW treatment at 200 °C. High‐molecular‐mass species decomposed under SCW treatment at high temperatures with consequent generation of smaller molecules. The antiradical activity of the SCW extract, determined by DPPH and ABTS assays, increased with increasing treatment temperature. The krill extracts and residues exhibited shrimp‐like flavour, and the most desirable flavour was obtained by SCW treatment at 140 °C or 160 °C for 10 min. The treatment would be applicable for the production of seasonings from Isada krill.     

粗颗粒盐渍土盐胀试验研究

盐渍土盐胀的影响因素很多,但主要与地基土中盐的含量、水、温度及地基土的渗透性有关。前人关于粗颗粒盐渍地基土盐胀性的研究中,由于工作主要集中在室内,难以模拟现场地层的实际情况,因此,对于盐胀性的认知一直难以统一。本文通过室内盐胀试验、室内外对比试验、现场试验,并与规范对比研究认为:粗颗粒盐渍土,当渗透系数小于10-7,且地层干燥,Na2SO4含量达到盐渍土的界限含量(0.3%)时,就应对其进行盐胀性评价。同时试验结果显示,地基土在200 k Pa大压力作用下,盐胀量仍然非常明显。     

植物乳杆菌SP-3对干酪挥发性风味物质的影响

采用固相微萃取(SPME)富集干酪模型中的挥发性风味物质,并以气相色谱—质谱联用仪(GC-MS)检测结果来评定植物乳杆菌SP-3对干酪挥发性风味的影响。结果表明,添加植物乳杆菌SP-3的干酪模型中2-丁酮、2-甲基-1-丙醇、3-甲基-1-丁醇、1-戊醇、4-甲基-2-戊醇、3-羟基-2-丁酮等具有坚果味、水果味和奶油味的物质明显高于对照组,而二甲基硫化物和3-甲硫基-1-丙醇的浓度则低于对照组。     

转变老观念开发新产品开创西凤酒销售新局面

适应市场需要,转变死守凤香型酒的老观念,开发凤兼浓香型和凤浓酱香型西凤酒,自主经营和买断经营相结合,使西凤酒重获生机.     

猕猴桃香精的调配

简要论述了猕猴桃香精的香气挥发性成分及其香气类型，同时在此基础上给出了一个猕猴桃香精配方。     

PCR‐DGGE analysis on microbial communities in pit mud of cellars used for different periods of time

Polymerase chain reaction denaturing gradient gel electrophoresis (PCR‐DGGE) was used to analyse microbial community evolution in the pit mud of cellars used for different periods of time in production of Chinese Luzhou‐flavour liquor. The pit mud was collected from the cellars and the microbial DNA was extracted from the microbes in the pit mud. The Bf 968 primer was used for PCR‐DGGE to analyse the variable region 6 (V6) to variable region 8 (V8) of the microbial 16S rDNA. It was found that the band number, dominance, diversity and similarity of the 16S rDNA were clearly different in the DGGE patterns, because of the great diversity expressed by the different microbial communities in the different‐aged cellars. It is concluded that mutual collaboration and constraint exist between the different microbial communities in the different‐aged cellars, and this relationship leads to an evolutional change in the structures and in the numbers of the microbial communities in the pit mud of the cellars. Changes become more obvious with increasing age of the liquor cellars. Copyright © 2012 The Institute of Brewing & Distilling