TP-Lips/LZM-CS复合缓释涂膜对美国红鱼鱼片贮藏品质的影响

目的提高复合缓释涂膜对美国红鱼鱼片的保鲜性能,获得具有长效作用的高效保鲜材料。方法将具有缓释作用的茶多酚脂质体(TP-Lips)与溶菌酶(LZM)复合后加入至壳聚糖(CS)涂膜液中,采用流延法制备TP-Lips/LZM-CS复合缓释涂膜。以美国红鱼鱼片的新鲜度为指针,评价复合涂膜的保鲜性能。结果 TP-Lips/LZM-CS复合缓释涂膜可有效抑制鱼肉中微生物的生长,延缓鱼片pH、硫代巴比妥酸(TBA)值的升高和鱼肉质构指标的变化。结论 TP,LZM和CS的复合使用有效地拓宽了抗菌谱,同时,脂质体和涂膜共同组成的缓释体系,使TP和LZM的作用时间更长,TP-Lips/LZM-CS复合涂膜的保鲜性能最优,并能够将4℃下冷藏美国红鱼鱼片的货架期延长至15 d以上。     

FG/CS逐层复合保鲜涂膜对三文鱼鱼片品质的影响

目的为了提高复合涂膜对三文鱼鱼片的保鲜性能,获得具有高效长效缓释性能的生物保鲜材料。方法以亚麻籽胶(FG)和壳聚糖(CS)为成膜材料,丁香酚(EG)和月桂精油(LEO)为保鲜剂,采用流延法制备逐层FG/CS+EG/FG+LEO复合涂膜。以三文鱼鱼片为研究对象,评估复合涂膜的保鲜性能。结果 FG/CS+EG/FG+LEO复合涂膜能够显著抑制三文鱼鱼肉中微生物的生长,提高鱼肉持水力,延缓脂肪氧化、蛋白质分解和色差值的变化进程。结论 EG和LEO复配使用具有一定的协同增效作用,同时,多层涂膜组成的缓释体系有效地延长了生物保鲜剂的作用时间,使EG和LEO对鱼片的保鲜效果更好,其中FG/CS+EG/FG+LEO复合涂膜的保鲜效果最优,可使生鲜三文鱼鱼片的货架期从7 d延长至13 d。     

冷藏过程中调味料对海鲈鱼片品质的影响

目的 研究复合调味料对海鲈鱼片贮藏品质的影响,以期为海鲈鱼的保鲜提供理论指导和技术支持.方法 以海鲈鱼片为研究对象,采用花椒、桂皮、八角、白酒、生姜、食盐等6种调味料及其复合物的溶液浸渍海鲈鱼片,测定4℃贮藏条件下海鲈鱼片的鲜度和质构指标的变化.结果 单一调味料液处理可使鱼片的鲜度和质构指标变化减缓,其中桂皮调味料液处理有效延缓了鱼片的菌落总数、pH值、硫代巴比妥酸(TBA)值、挥发性盐基氮(TVB-N)值和K值的上升.经复合调味料液处理后,鱼片的各项鲜度指标均有所改善,且自由水的含量显著降低,持水力比未处理鱼片高出8％,改善了鱼肉的持水性.结论 6种调味料复合后具有协同抗菌性能,保鲜性能较好,可有效延缓海鲈鱼的蛋白质分解和脂肪氧化,延长货架期至12 d.     

复合生物保鲜剂对冷鲜牛肉的保鲜效果研究

目的为了延长冷鲜牛肉的货架期,提高冷鲜牛肉贮藏期间的品质,研究复合生物保鲜剂的保鲜效果。方法利用多种生物保鲜剂对冷鲜牛肉进行处理,并在室温下进行贮藏,每隔3 d对冷鲜牛肉的含水量、pH和TVB-N值进行测定,并根据单因素实验所得结果,选择效果明显的保鲜剂按照一定比例组成复合生物保鲜剂,对冷鲜牛肉进行处理,并检验其保鲜效果。结果生物保鲜剂处理后的冷鲜牛肉的储存期和品质均较未处理的试样有明显提升,其中壳聚糖、茶多酚和溶菌酶的保鲜效果更明显,因此,选择这3种保鲜剂作为复合保鲜剂对冷鲜牛肉进行处理,在4℃条件下贮藏,并在第6天对其挥发性盐基氮进行了测定,分析结果表明,当壳聚糖、茶多酚和溶菌酶的质量分数分别为5%,1%,3%时,冷鲜牛肉的TVB-N取极小值59.2 mg/kg,仍然保持比较新鲜的状态。结论复合生物保鲜剂对冷鲜牛肉具有比较明显的保鲜作用,能够有效地延长肉品的货架期。     

金枪鱼生物保鲜技术的研究进展

目的 综述生物保鲜剂在金枪鱼贮藏中的研究现状。方法 首先分析金枪鱼贮藏过程中常见的腐败微生物, 其次介绍抗氧化生物保鲜剂、 抑菌生物保鲜剂、 复合保鲜剂在金枪鱼保鲜中的应用现状。结果 金枪鱼贮藏过程中常见的腐败微生物为假单胞菌、 腐败希瓦氏菌等, 生物保鲜剂的复合使用以及与气调包装技术结合可增加保鲜效果, 延长货架期。结论 生物保鲜, 尤其是复合保鲜剂以及生物保鲜剂与其他物理保鲜技术相结合在金枪鱼保鲜中极具发展潜力。     

气调包装协同天然保鲜剂对冷却牛肉的保鲜研究

研究了气调包装与复合天然保鲜剂联合使用对冷却牛肉保鲜的效果。将复合保鲜剂与高氧浓度的各种气调包装协同使用,并且在(4±1)℃条件下贮藏,以真空包装为对照,对牛肉菌落总数、pH值、挥发性盐基氮、液汁流失率、嫩度、弹性、色泽等指标进行检测分析,确定了延长牛肉货架期的较佳条件为:气调包装气体体积分数为70%O2/20%CO2/10%N2,复合保鲜剂为质量分数1%壳聚糖/0.2%茶多酚。     

精油微胶囊在食品保鲜中的应用研究进展

目的 综述精油微胶囊在食品保鲜领域的研究进展,为进一步开发精油微胶囊在食品保鲜中的应用提供科学的研究基础.方法 归纳近几年制备精油微胶囊的方法及其特点,简要介绍微流控法、反向分散凝胶法、层层自组装法及电喷雾法.总结精油微胶囊在食品保鲜中的应用方式以及在果蔬、冷鲜肉制品、加工制品、粮食作物等方面的应用研究.结果 微胶囊技术可以扩大精油在食品工业中的应用,精油微胶囊作为新型的天然保鲜剂用于食品贮藏中能抑制微生物生长,延长食品的货架期.结论 精油微胶囊在食品保鲜领域有较大发展潜力.     

固载二氧化氯缓释保鲜剂对巨峰葡萄保鲜效果的研究

研究了常温下自制固载ClO2缓释保鲜剂对巨峰葡萄保鲜效果的影响,评价了贮藏期间葡萄的品质变化.结果表明:低浓度的ClO2气体缓释保鲜剂(ClO2释放速率小于20μg/h)能够有效抑制霉菌的生长,延缓果品品质的下降,从而延长了巨峰葡萄的货架寿命.     

1-MCP复合GA3处理对乌龙头贮藏品质的影响

目的 为探究不同保鲜剂对乌龙头贮藏品质的影响,筛选出适宜的保鲜剂,为乌龙头贮藏保鲜提供参考依据。方法 以“长白”乌龙头为研究对象,分别采用含量为3 μL/L的1-甲基环丙烯(1-MCP)熏蒸12 h、质量浓度为200 mg/L的赤霉素(GA3)溶液浸泡3 min和含量为3 μL/L的1-MCP熏蒸12 h后于质量浓度为200 mg/L的GA3溶液中浸泡3 min,浸泡后晾干,于0 ℃下贮藏,每隔4 d测定乌龙头的感官品质、腐烂指数、呼吸速率、质量损失率、叶绿素含量、色度值、粗纤维含量、丙二醛(MDA)含量、过氧化物酶(POD)活性和多酚氧化酶(PPO)活性等指标。结果 对照处理于0 ℃下贮藏期仅为12 d,贮藏后期出现感官品质下降、叶绿素流失、PPO和POD活性增高、异味严重的现象,失去商品性。贮藏期间,各保鲜剂处理能显著延缓采后“长白”乌龙头感官品质的下降,抑制呼吸速率、腐烂指数和粗纤维含量的升高,有效保持叶绿素含量和色度a^*值,抑制MDA含量的积累,同时能够抑制贮藏期间乌龙头的POD和PPO活性的上升,提升其抗氧化能力。其中,以1-MCP复合GA3处理后的保鲜效果最佳,保鲜效果优于单一保鲜剂处理。贮藏20 d时,1-MCP复合GA3处理组乌龙头的感官品质为80.2、腐烂指数为0.02、质量损失率为6.44%、叶绿素含量为3.7 mg/g、色度a^*值为−5.1、MDA的含量为4.7 μmol/g、POD活性为37.2 U/g、PPO活性为16.6 U/g。结论 1-MCP复合GA3处理后的保鲜效果最佳,能够抑制乌龙头腐烂,保持其营养品质,贮藏期延长了8 d。     

菊粉天然复合保鲜剂对冷鲜猪肉保鲜效果的影响

目的 通过研究菊粉天然复合保鲜剂对冷鲜猪肉保鲜效果的影响,为冷鲜猪肉保鲜提供实验数据基础。方法 以冷鲜猪肉的感官评价为依据,分别采用单因素实验和响应面法优化菊粉天然复合保鲜剂（菊粉、壳聚糖、茶多酚和Nisin）配方,并考察其对贮藏期冷鲜猪肉感官品质、pH值、汁液流失率、脂肪氧化程度（TBA值）和菌落总数等指标的影响。结果 得到了菊粉天然复合保鲜剂的优化配方,菊粉为35.2 g/L,壳聚糖为21.5 g/L,茶多酚为9.5 g/L,Nisin为0.16 g/L。优化的菊粉天然复合保鲜剂可改善冷鲜猪肉的感官品质,减少汁液流失,减缓pH值和TBA值的升高及抑制细菌生长速度。在4 ℃贮藏条件下,可使冷鲜猪肉的货架期延长6 d。结论 菊粉天然复合保鲜剂能有效保持冷鲜猪肉的商品价值,可用于冷鲜猪肉的保鲜。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

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.     

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.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

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.     

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.