嗜酸乳杆菌对蓝靛果汁降酸效果的研究

目的 以蓝靛果汁为原料,选取嗜酸乳杆菌通过发酵降低果汁的酸度,以达到改善果汁口感的目的。方法 研究以果汁降酸率为指标,经单因素和正交试验优化工艺条件,并测定降酸前后果汁中主要有机酸含量变化情况和果汁相关指标。结果 得到的最佳降酸工艺条件为发酵温度34 ℃、菌接种量2.5×107 CFU/mL、初始pH值3.4、葡萄糖添加量（质量分数）3%、胰蛋白胨添加量（质量分数）3%,此条件下果汁的降酸率达到86.32%。采用HPLC法测得果汁中苹果酸、柠檬酸的含量分别下降了49.37%、36.05%,花色苷、还原糖等指标有小幅下降。结论 嗜酸乳杆菌可有效应用于蓝靛果汁降酸处理中,有利于提升果汁的口感。     

刺梨果酒发酵技术研究

干酵母的扩大培养级数、驯化培养、酒母添加量、温度等因素都会对刺梨果酒的发酵产生影响。以新鲜刺梨全汁为原料,接种经活化、驯化培养的酒母,控温发酵。试验表明,添加4%经驯化培养的酒母,22±1℃控温发酵,主发酵16d,发酵酒风味品质较好。     

直投式发酵剂生产炭烧酸奶工艺及最优包装

目的研究直投式发酵剂生产炭烧酸奶的工艺和最优包装。方法以鲜牛奶为原料,经过美拉德反应后生成褐色牛奶,再经过接种,加入添加剂,并进行发酵、后熟处理,最终制出炭烧酸奶,选出透明、避光这2种包装中较优的包装。结果制备褐色牛奶的最佳工艺中,添加葡萄糖的质量分数为5%,水浴温度为98℃,水浴时间为180 min。使用该褐色牛奶作为原料进行发酵,制备的炭烧酸奶最佳工艺配方中,蔗糖质量分数为4%,脱脂奶粉质量分数为5%,菌种质量分数为0.25%,发酵温度为41℃,发酵时间为360 min,其中避光包装更利于酸奶贮存。结论在最佳工艺条件下生产的炭烧酸奶呈咖啡色,色泽均匀光滑,有醇正的焦糖风味和酸奶风味,组织状态稳定,口感细腻,黏稠感适中,无乳清析出,蛋白质含量远高于市售炭烧酸奶。     

醋酸菌菌膜生产工艺条件优化

目的 优化用醋酸菌生产菌膜的最适培养条件和方法，以期获得天然、安全的食品包装用膜的生产工艺。方法 以涩柿醋为原料，分离筛选出高产菌膜的优良醋酸菌种，通过单因素和Plackett?Burman 等试验设计优化醋酸菌菌膜最适培养方法和工艺条件。结果 从涩柿醋中分离纯化获得产膜醋酸菌，经鉴定为葡糖醋杆菌。用醋酸菌生产醋酸菌菌膜最优培养条件:蔗糖质量分数为5%、蛋白胨质量分数为0.7%、酵母提取物质量分数为1.2%、柠檬酸钠质量分数为0.15%、K2HPO4质量分数为0.16%、乙酸体积分数为1%、无水乙醇体积分数为2%，种龄为32 h，接种量为9%;培养5 d后，醋酸菌菌膜的平均产率为364.65 g/L，是优化前的(246.03 g/L)的1.48倍。湿膜平均含水率为99.38%，复水率为71.09%～83.39%，菌膜干膜复水率高且复水速度快，复水1 min其含水率便可达到70%以上。结论 醋酸菌用经过优化选择的培养液和方法，可生产出高质量的菌膜。     

草莓酸奶发酵工艺研究

草莓是一种口感极佳营养丰富的水果,本研究主要以新鲜的草莓和牛奶为原料,选取嗜热杆菌和德氏保加利亚杆菌混合发酵制作的一种新的风味产品。通过感官评价和实验探索确定了乳酸菌接种量4%,发酵温度44℃,发酵时间2.5h,草莓汁添加量为7%时产品的质量最好品质最佳的发酵条件。     

食品接触材料PVC中32种增塑剂在4种食品模拟物中的迁移规律研究

在不同的条件下,将含有已知量增塑剂的PVC薄膜,在水、乙酸(体积分数为3%)、乙醇(体积分数10%)和橄榄油等4种食品模拟物中浸泡,在规定的时间点抽取一定量的浸泡液,采用气相色谱-质谱法测定增塑剂含量,研究迁移量及迁移率与时间、温度、模拟食品属性、增塑剂初始浓度及包装材料厚度等参数的关系。结果表明:食品模拟物的食品属性对增塑剂的迁移行为有显著影响;增塑剂溶出种类数、迁移量和迁移率随温度升高显著增加;薄膜厚度增加,则增塑剂迁移量大,迁移率降低;薄膜中增塑剂初始浓度高,则迁移量大,迁移率低。     

高含量低聚果糖的生产工艺研究

将种子液培养与发酵培养结合为一个步骤,并对这种新的低聚果糖合成方法做了初步的基础性研究.研究结果表明,将种子液培养与发酵培养相结合为一个环节,通过优化生产条件,可以使低聚果糖的产率大幅度提高.该法的最适条件为:接种量5%,温度30℃,初始pH7.0,培养时间48 h,初始蔗糖浓度50%,制得的低聚果糖产率为75.21%.该法不仅使寡果糖产率得到大幅度提高,而且可简化工艺,节约资源.     

薏米与番石榴复合乳酸发酵饮料的研制

目的结合薏米与番石榴的功能优势及感官优势,利用乳酸菌发酵研制出新型薏米与番石榴复合乳酸发酵饮料,并对其风味进行分析,以期为薏米和番石榴资源的利用及其乳酸饮料的研发提供理论和实践依据。方法以乳酸发酵饮料中的感官评分为考察指标,选取番石榴与薏米的质量比、发酵时间、发酵温度、乳酸菌添加量、蜂蜜添加量作为考察指标,在单因素试验的基础上,采用正交试验设计对薏米番石榴乳酸发酵饮料的制作工艺进行优化。结果得到了各因素对薏米番石榴乳酸发酵饮料感官评分影响的顺序,发酵温度>乳酸菌添加量>发酵时间>番石与榴薏米的质量比;得到了最佳工艺条件,发酵温度为38℃,乳酸菌的质量分数为0.6%,发酵时间为28 h,番石榴与薏米的质量比为6∶4,在此条件下,很好地保留了发酵饮料的活性成分,口感酸甜适宜,营养丰富,状态均一、稳定,无分层现象,感官评分为96.6,总酸含量为7.62 g/L。结论通过实验分析,确定了薏米番石榴乳酸发酵饮料的最佳工艺条件。     

可见光宽波带减反超疏玻璃的制备工艺及结构探讨

高透射率和自洁净复合功能化是光伏玻璃研究热点。利用光伏玻璃原片，以乙二胺四乙酸二钠(EDTA-2Na)和乙二胺四乙酸四钠(EDTA-4Na)混合溶液为刻蚀液，通过水热刻蚀，再经十二烷基三乙氧基硅烷(DTES)疏水修饰，成功得到具有可见光宽波带(380～780 nm)减反超疏玻璃。探究了水热温度、反应时间、络合物混合比例、络合物添加量对膜层结构和光学性能的影响，以及疏水剂涂覆工艺和预处理时间对表面润湿性的影响。在160℃、8 h,刻蚀液中络合物为EDTA-2Na(40%,体积分数)与EDTA-4Na(60%,体积分数)、EDTA-nNa (0.34 mol/L)总添加量为4%(体积分数)时，所得玻璃的可见光380～780 nm各个波长的反射率小于1%;总反射率为0.45%,总透射率为98.85%,雾度为0%。采用旋涂法涂DTES进行表面疏水修饰，预水解时间为18 h时，可获得超疏水性能，水接触角为150.86°,滚动角为5.9°。表面疏水修饰对减反射性能影响很小。     

黑蒜黑枸杞复合饮料制备过程中酶解工艺优化

目的以黑蒜、黑枸杞等为主要原料,以出汁率、透光率、饮料中花色苷含量和DPPH自由基清除率为依据,研究酶解条件对复合饮料产率和稳定性的影响。方法选择纤维素与果胶酶比例、复合酶添加量、酶解温度和酶解时间为自变量的4因素3水平的正交实验优化酶的最佳酶解条件。结果各因素对复合饮料的模糊综合评分值的影响主次顺序为复合酶添加量酶解温度酶解时间复合酶比例;最佳酶解工艺条件,复合酶质量分数0.06%,纤维素酶与果胶酶的质量比为2︰1,酶解温度为50℃,酶解时间为3 h。在此优化工艺条件下,出汁率为91.04%,透光率为77.27%,饮料中花色苷的质量浓度为167.11 mg/L,DPPH自由基清除率为58.81%。结论该工艺生产的复合饮料出汁率高,抗氧化活性强。     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.