Volatile Flavor Components from Boiled Crayfish (Procambarus clarkii) Tail Meat

The volatile flavor components of boiled red swamp crayfish (Procambarus clarkii) tail meat were characterized by a combination of dynamic headspace concentration on a porous polymer trap, high resolution gas chromatography, mass spectrometry and chromatography-coupled aroma sniffing evaluation. A total of 70 volatile compounds in many different chemical classes were identified and reported for the first time in crayfish tail meat. Various components gave green grassy, woody, buttery, metallic, or sulfur-like aroma characteristics. Most of the sensory characteristics of the individual components in the aromagram agreed well with the identification of the chemical structures eluted within the corresponding chromatographic period. However, several pleasant nutty, meaty and salty-meaty areas in the gas chromatographic aromagram remained unidentified.     

Rheological Properties of Mozzarella Cheese Filled with Dairy, Egg, Soy Proteins, and Gelatin

The Rheological behavior of mozzarella cheese filled with various proteins (whey protein, caseinate, egg white, soy protein isolate, gelatin) incorporated was determined by uniaxial compression at 10°C and the effect of temperature (10°C?60°C) by dynamic measurement. Mozzarella cheese with whey protein, caseinate, egg white, and soy protein isolate showed significant water retention during heating. Among the proteins, soy protein isolate induced the strongest gel network structure with mozzarella cheese. All proteins altered the viscoelastic properties of mozzarella cheese.     

Copper Activity in Sucrose Solutions

Copper activity was measured by a cupric electrode in 0.1 M sodium acetate-acetic acid buffered (pH 3.2, 4.5, 6.0) and unbuffered sucrose solutions (10% w/v) using the standard addition technique (l–10 ppm of Cu⁺⁺). In water, the measured copper concentration (activity) was linearly related to the added copper concentration with a slope of unity. The slope decreased in acetate buffer solutions as pH increased indicating that Cu⁺⁺ was complexed with acetate and to a greater extent at higher pH. In the presence of sucrose, copper activity increased approximately 16% in all solutions. Results suggest that the bulking effect of sucrose and the decreased water activity in solutions produced increased copper activity in sucrose solutions.     

Draw pH and Storage Affect Rheological Properties of Mozzarella Cheese

Cheeses with whey pH at draw of 6.15 or 6.40 were stored at 4°for 50 days. Compression test at 10°(Instron) showed a decrease in compressive stress with storage. Failure points were near a true strain value of 0.5 for the cheeses at day 3. The failure region became less obvious by day 50. The hypothetical equilibrium stress (HES) in the stress-relaxation test was higher with a draw pH of 6.40 than 6.15, possibly indicating that higher calcium led to a stronger network structure. The HES decreased with storage, suggesting cleavage of structural crosslinks caused by the coagulant.     

NEW MELT CONVEYING MODELS FOR A SINGLE SCREW EXTRUDER1

The flow theory in an extruder is fundamental to the study of extrusion technology. Present analytical solutions of the flow theory used in many studies give significant overpredictions of the volumetric flow rate due to erroneous boundary conditions used. Modified flat plate models with and without considering side wall effect and a coaxial cylinder model for Newtonian fluids were derived in this study using new boundary conditions confirmed by Choo et al. (1980). Using experimental data from published literature, it was found that the volumetric flow rates in the extruder were better predicted by these models than the numerical solutions or the original analytical solutions.     

Simultaneous Analysis of Biogenic Amines in Canned Fish by HPLC

A simple HPLC method was developed for simultaneous determination of putrescine, cadaverine, tryptamine, 2-phenylethylamine, spermidine, spermine, histamine, tyramine, and agmatine. Amines were derivatized with benzoyl chloride and separated well on Lichrosphere are 100 RP-18 column using a gradient elution system with a mixture of methanol and water in 10 min. Amine content of canned fish was detected by this method, and except for anchovie products most samples contained the nine amines at low levels. This method would be useful for detection of amines in fish.     

Factor analysis for the statistical modeling of earthquake-induced landslides

Earthquake-induced landslides are difficult to assess and predict owing to the inherent unpredictability of earthquakes. In most existing studies, the landslide potential is statistically assessed by collecting and analyzing the data of historical landslide events and earthquake observation records. Unlike rainfall-induced landslides, earthquake-induced landslides cannot be predicted in advance using real-time monitoring systems, and the development of the models for these landslides should instead depend on early earthquake warnings and estimations. Hence, in this study, factor analysis was performed and the frequency distribution method was employed to investigate the potential risk of the landslides caused by earthquakes. Factors such as the slope gradient, lithology (geology), aspect, and elevation were selected and classified as influential factors to facilitate the construction of a landslide database for the area of study.     

石材裂纹扩展分形特性

利用楔形劈裂试验系统观测石材裂纹起裂与扩展,利用应变片系统量测出试件在不同加载速率下裂纹尖端附近裂纹扩展速度的分布及其分形特性。所得结果如下：在考虑不同加载速率下,得到在静态或准静态加载条件下试体的断裂韧性基本上变化不大;但加载速率愈快,裂纹扩展实测平均速度愈高。考虑分形特性,在相同加载速率条件下,所得分形维数越大,则分形裂纹速度也越大,这与理论推导是相符的;分形维数与相关参数（断裂韧性、加载速率）的关系,在静态或准静态加载下近似为一个常数关系。