西藏青稞酒酿造小曲微生物多样性分析

该研究利用高通量测序技术分别对西藏自治区五个地区的青稞酒酒曲样品的微生物组成和差异性进行分析。 结果表明, 21种酒曲样品中共检测出真菌140种、69个属,细菌967种、309个属,其中,昌都、山南、拉萨曲水县和林芝地区青稞酒酒曲微生物种 类相对丰富,日喀则地区青稞酒酒曲微生物种类相对较少。 西藏五个地区青稞酒酒曲样品的共有优势真菌菌属为覆膜孢酵母属（Saccharomycopsis）、根霉属（Rhizopus）和毛霉属（Mucor）,优势细菌菌属为乳酸杆菌属（Lactobacillus）和明串珠菌属（Leuconostoc）。 西藏不同地区青稞酒酒曲样品微生物均存在一定差异。     

Short communication: Effect of milk and milk containing Lactobacillus casei on the intestinal microbiota of mice

BALB/c mice were fed milk or Lactobacillus casei BL23 in milk for 14 d and fecal samples were collected at d 0, 4, and 7 as well as 1 and 8 d after the last administration. According to high-throughput DNA sequencing of the 16S rRNA genes extracted from the fecal microbiota, the bacterial diversity in the fecal samples of all mice increased over time. After 14 d of administration, the consumption of milk and milk containing L. casei BL23 resulted in distinct effects on the microbial composition in the intestine. Specifically, the proportions of bacteria in the Lactobacillaceae, Porphyromonadaceae, and Comamonadaceae were significantly higher in mice fed the L. casei BL23-milk culture compared with one or more of the other groups of mice. The relative amounts of Lachnospiraceae were higher and Streptococcaceae were lower in mice fed milk alone. The changes were not found at d 4 and 7 during milk and L. casei feeding and were no longer detected 8 d after administration was stopped. This study shows that consumption of milk or probiotic L. casei-containing milk results in non-overlapping, taxa-specific effects on the bacteria in the distal murine intestine.     

Direct electrochemistry of guanosine on multi-walled carbon nanotubes modified carbon ionic liquid electrode

A multi-walled carbon nanotubes (MWCNTs) modified carbon ionic liquid electrode (CILE) was fabricated and used to investigate the electrochemical behavior of guanosine. CILE was prepared by mixing hydrophilic ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF₄), graphite powder and liquid paraffin together. The fabricated MWCNTs/CILE showed great electrocatalytic ability to the oxidation of guanosine and an irreversible oxidation peak appeared at 1.067 V (vs. SCE) with improved peak current. The electrochemical behavior of guanosine on the MWCNTs/CILE was carefully studied by cyclic voltammetry and the electrochemical parameters such as the charge transfer coefficient (α) and the electrode reaction standard rate constant (k_s) were calculated with the result as 0.66 and 2.94 × 10⁻⁴ s⁻¹, respectively. By using differential pulse voltammetry (DPV) as the detection method, a linear relationship was obtained between the oxidation peak current and the guanosine concentration in the range from 1.0 × 10⁻⁷ to 4.0 × 10⁻⁵ mol/L with the detection limit as 7.8 × 10⁻⁸ mol/L (3σ). The common coexisting substances showed no interferences to the guanosine detection and the modified electrode showed good ability to distinguish the electrochemical response of guanosine and adenosine.     

应用高通量测序技术研究新疆产区葡萄果实、叶片及果园土壤微生物多样性

利用高通量测序技术分析中国新疆酿酒葡萄产区3?个葡萄园的土壤、葡萄叶片和酿酒葡萄中的微生物组成和多样性。结果表明从27?个样品中共得到1?043?102个高质量真菌序列代表,包括5?个菌门、237?个真菌菌属;共得到2?422?188?个高质量细菌序列代表,包括8?个菌门、314?个细菌菌属。无论是真菌还是细菌,土壤中微生物种类最为复杂、数量最多,其次是葡萄叶片和酿酒葡萄。土壤中真菌以Saccharomyces、Sordaria、Tetracladium和Geomyces为主,细菌以Arthrobacter、Kaistobacter和Skermanella为主;酿酒葡萄和葡萄叶片中真菌以Aureobasidium、Cryptococcus、Aspergillus和Sporospora为主,细菌以Pseudomonas、Sphingomonas和Adhaeribacter为主。葡萄园地理位置不同,微生物的多样性也存在差异。酿酒葡萄园复杂的微生物区系研究,对进一步开发产区特色微生物的筛选和利用提供了理论支持。     

响应面优化HS-SPME-GC/MS检测啤酒微量酯类物质条件

该研究采用Plackett-Burman和Box-Behnken试验设计,对顶空固相微萃取-气相色谱-质谱法（HS-SPME-GC/MS）检测啤酒中6种低含量酯类物质（辛酸乙酯、丁酸乙酯、乙酸异丁酯、乙酸苯乙酯、苯甲酸乙酯和3-苯基丙酸乙酯）的萃取条件进行优化,发现萃取温度、萃取时间和平衡温度为主要影响因素,通过响应面法分析得出最佳萃取条件为：萃取温度42 ℃、萃取时间30 min和平衡温度48 ℃;在该条件下,结合内标法定量,该方法的相关系数R2为0.990 0～0.999 9,回收率为93.43%～103.37%,检测限为0.01～0.05 μg/L,相对标准偏差（RSD）为1.75%～8.24%,表明该方法准确可靠,可应用于啤酒中微量酯类物质的检测。     

产吡嗪类细菌的麸曲制作工艺优化

该文采用响应面法对产吡嗪细菌的麸曲制作工艺进行研究。以从酒曲中筛选的细菌为基础,考察不同因素对细菌产吡嗪的影响。采用单因素试验和响应面法对影响麸曲制作中细菌产吡嗪的4个主要影响因素即麸皮添加量、水分、培养时间和接种量进行分析优化。结果表明,影响细菌产吡嗪的工艺因素按主次顺序排列为麸皮添加量＞接种量＞水分含量＞培养时间;确定麸曲制作中细菌产吡嗪的最佳工艺条件为麸皮添加量115 g、水分含量30%、培养时间36 h、接种量12%。在此最佳条件下,吡嗪类物质的产量36.36×10-5 g/g。     

基于蜗杆蜗轮与曲柄连杆传动的二次串联增力手动夹具

介绍了一种基于杆蜗轮一曲柄连杆机构的二次串联手动增力夹具的工作原理．给出了其力学特性及计算公式。该机构由人工转动蜗杆提供动力，通过曲柄连杆增力机构实现二次力放大，夹紧工件。该装置结构紧凑，操作简单，柔性好，绿色化程度高，节约能源。     

黄酒酿造过程中优势细菌产生物胺的检测与评价

采用显色培养基法、脱羧酶序列特异PCR技术和HPLC分析脱羧酶液体培养基生物胺含量变化3种方法检测和评价来自黄酒酿造过程的41株细菌产生物胺的情况。研究表明,3种方法检测结果大致相同,互补使用能够准确分析细菌产生物胺的情况;41株细菌中,53.7%以上都能产酪胺,31.7%以上产腐胺,24.3%以上产组胺;14株短乳杆菌均携带酪氨酸脱羧酶基因,其中11株菌的酪胺产量超过50.00 mg/L,且多数菌能代谢产生多种生物胺,因此推断其对黄酒中生物胺含量影响最大;细菌代谢是否产生物胺及产生物胺的能力无种属特异性,但有菌株特异性。     

浓香型白酒窖泥钙化成因及缓解措施的初步探究

窖泥对于浓香型白酒的品质起着重要的作用,而目前各大酒厂窖池中的窖泥却频频出现钙化问题,直接影响了白酒的酒质。该研究通过对钙化窖泥和优质老窖泥在理化指标方面进行对比,得出窖泥钙化的主要原因是：由于窖泥中水分降低、pH降低等因素,导致窖泥中形成乳酸钙、乳酸铁等白色晶体,使得窖泥板结、出现白斑,质量下降。鉴于此,该研究采取在窖泥中加入产碱杆菌（Alcaligenes sp.）、酒花酸浸提液和乳酸链球菌肽（Nisin）3种措施,以此来缓解窖泥的钙化问题。结果表明,发现3种措施均能够缓解窖泥的钙化,且3种措施缓解的侧重点不同,综合分析后发现加入Nisin的效果最佳。     

两种发酵工艺下低盐固态酱油中生物胺的变化

生物胺常被作为衡量食品安全水平的标志.本研究采用高效液相色谱法分别测定2种发酵工艺下低盐固态酱油中生物胺的变化,同时检测分析发酵过程中微生物数量、水分含量、氯化钠含量的变化情况.结果表明,肠道菌的数量与组胺、酪胺的含量积累有密切关系:相较于移位发酵法,采用原池淋浇发酵工艺其发酵末期的酱醅中水分和氯化钠的含量更高;苯乙胺和腐胺是移位发酵工艺主要的生物胺,腐胺、组胺和酪胺是原池淋浇发酵工艺主要的生物胺.