Efficiency of Removing Volatiles from Menhaden Oils by Refining, Bleaching, and Deodorization

Atlantic and Gulf of Mexico menhaden (Brevoortia spp) oils from refining, bleaching and deodorizing steps were analyzed for volatile components by combined techniques of dynamic headspace sampling, high resolution gas chromatography and mass spectrometry. Results indicated that alkali-refining and clay-bleaching removed many odorous short-chain oxygenated compounds and alkylbenzenes; steam-deodorization (200–208°C, 3 hr) eliminated most volatiles. Some volatiles in deodorized samples were attributed to container material and antioxidants.     

管幂进洞工法在山谷地形浅覆隧道中的应用与补强对策

 近年来,随着环境保护观念的提升,减少地表开挖的理念已逐渐落实在隧道设计及施工上。在隧道洞口浅覆段采用的明挖法已逐渐被暗挖法所取代,即使在地质、地形条件上不尽理想的区段,考虑到整体路线及水资源保护等因素,也是如此。以台湾北部一正施工中的双线双车道公路隧道为例,探讨管幂工法在浅覆盖采用暗挖法所面临的困难及其对策。由于该案例处于山凹处,洞口浅覆盖厚度约100 m。开挖过程中,因为遭遇到地质变异,多雨的气候与谷部入洞的地形,使得降雨所汇集的地表水,不断入渗至隧道内,开挖面自立性极差。故施工进洞时,原设计采用的管幂工法几乎难以进行。经采取拱盖培厚及双层管幂等补强对策后,勉强施工,其处理经验与心得,可为以后类似工程提供参考。     

液晶荧幕中卷动文件对视觉绩效与视觉不适之研究

汽车液晶荧幕愈来愈广泛,其中文件浏览工具为一种应用范围.浏览文字或图片资讯时,大部分软件都提供可以缩放荧幕文件大小与卷动文字页面这些功能.然而,有时持续性的跳动对视觉产生很大影响,眼睛随著快速的卷动很容易造成疲劳与不适.在快速卷动下,文字太小,不容易辨识,文字太大,也容易产生模糊.本研究利用阅读文件来了解卷轴速度与缩放比例对视觉绩效与疲劳之影响.结果得知缩放比例对于视觉疲劳有显著影响,因此,文件浏览工具的设计可以改善视觉不适的现象.     

Monoclonal Antibodies to Porcine Thermal-Stable Muscle Protein for Detection of Pork in Raw and Cooked Meats

Four hybridoma cell lines secreting monoclonal antibodies (MAbs) specific to porcine thermal-stable muscle proteins (TSMPs) were developed. The MAbs reacted with three protein bands (20.5, 22 and 24 kD) from raw pork extract; the protein band (24 kD) which was also present in cooked pork was identified as porcine-specific TSMP. Epitope analysis indicated four MAbs recognized same or closely located antigenic sites on the pork TSMP. The developed MAb-based indirect enzyme-linked immunosorbent assay (ELISA) enabled the detection of pork in raw and cooked heterogeneous meat mixtures as low as 10 g/kg. The curvilinear relations of second-degree polynomial (r² > 0.995) between pork concentrations and ELISA responses enabled quantifying degree of adulteration of pork in meat products.     

Comparison of the Real-time Microrespirometer and Aerobic Plate Count Methods for Determination of Microbial Quality in Ground Beef

ABSTRACT Real-time microrespirometer measurements were compared with the aerobic plate count (APC) method to assess microbial quality of ground beef stored at 4°C and 7°C with and without previous freezing. The samples were monitored daily for CO2 evolution rate (CER) using a microrespirometer, APC, and were evaluated for color and odor changes by a sensory panel. The CER was highly correlated with the APC for all storage conditions ( r 2 = 0.787 to 0.952). The onset of meat spoilage was more closely associated with a specific CER value (>25 μL/h/g) than APC. The new method was found to be more accurate in predicting meat spoilage, especially for previously frozen samples.     

A study on the nickel-rich ternary Ti–Ni–Al shape memory alloys

The transformation sequence and hardening effects of 400 °C aged Ti47.5Ni50.65Al1.85 and Ti49.5Ni50.13Al0.37 shape memory alloys have been investigated by electrical resistivity tests, internal friction measurements, hardness tests and TEM observations. Both solution hardening and precipitation hardening are found to occur in these alloys. The hardening effects of Ti47.5Ni50.65Al1.85 alloy are obvious and much higher than those of Ti49.5Ni50.13Al0.37 alloy due to the former having the larger Ni/Ti ratio and a higher Al solute content in its matrix. The transformation sequence of 400 °C aged Ti47.5Ni50.65Al1.85 alloy shows B2↔R-phase only for an ageing time of more than 10 h and that of 400°C aged Ti49.5Ni50.13Al0.37 alloy shows the sequence B2↔R-phase↔B19′ or B2↔R-phase with different ageing times. All of these characteristics are associated with Ti11Ni14 precipitates during the ageing process. These aged Ti–Ni–Al alloys exhibit very good shape memory effects, in which the maximal shape recovery occurs at the peak of hardness. This revised version was published online in November 2006 with corrections to the Cover Date.     

基于条件化有向图的工作流过程优化

为改善工作流的性能和效率,一个智能化的工作流管理系统应该具有分析和优化工作流过程定义的能力,该文首先给出影响工作流过程性能的主要因素,借助于定量分析的方法,讨论了这些因素对工作流性能和效率的影响,以此为基础,基于条件化有向图这种过程定义模型提出了一组对工作流过程进行优化的方法。     

Lipoxygenase-Catalyzed Oxidation of N-6 and N-3 Polyunsaturated Fatty Acids: Relevance to and Activity in Fish Tissue

Lipid peroxidation is an important process responsible for the flavor deterioration of many plant and animal foods. In order to understand possible mechanisms of initiation, a soybean lipoxygenase-polyunsaturated fatty acid model system was studied. The rate of enzyme-initiated oxidation was monitored by both oxygen consumption and diene conjugation. The hydroperoxides from an n-6 fatty acid, i.e. arachidonic, and n-3 fatty acids, i.e. linolenic, eicosapentaenoic, and docosahexaenoic acids were reduced and analyzed by reverse-phase high pressure liquid chromatography and gas chromatography/mass spectrometry. The lipoxygenase specifically catalyzed oxygenation at the n-6 carbon of both n-3 and n-6 fatty acids. Lipoxygenase activity was demonstrated in skin homogenate from rainbow trout and its role in off-flavor development is discussed.     

Step Changes in Screw Speed Affect Extrusion Temperature and Pressure and Extrudate Characteristics

A first order lag with time delay was used to model dynamic responses of product temperature, torque, and mass pressure to step changes in screw speed. Transportation lag was evident in the mass temperature at the die, while the time constants generally decreased with increased magnitude of the step input. Dynamic responses indicated a more stable response to larger magnitude of step inputs! Product attributes and process variables were shown to be a function of the magnitude of the step input when final screw speed set points were identical.     

SPECIES SUBSTITUTION OF RESTAURANT FISH ENTREES

Fish species substitution has been a common problem in the retail markets. However, this problem has not been documented in restaurant-cooked fish entrees. This study investigated fish substitution in restaurant-cooked snapper and swordfish entrees from four major cities in the U.S. The species of 16 snappers including 13 red snapper and 21 swordfish samples were verified as presented on the menu using isoelectric focusing (IEF). Fish samples were cleaned and desalted by rinsing with distilled water before protein extraction. Protein separation was carried out in a polyacrylamide gel with a wide pH gradient range of 3.5–9.5. Distinctive IEF protein band patterns of unknown samples were compared with the authentic standards. Six out of 13 (46%) red snapper samples and two out of 21 (10%) swordfish samples were misrepresented. The method used in this study adequately and efficiently verified the species of restaurant-cooked snapper and swordfish samples.