Improvement of carbon monoxide analysis in fish meat

Carbon monoxide (CO) treatment of fish meat of tuna, yellowtail, tilapia etc. is not allowed in Japan, since it can maintain the red color for a longer period than the microbiological shelf life of fish meat. The official method for quantification of CO has a problem, in that a part of the CO is lost during the preparation of the fish sample. To solve this problem, we modified the official method in this study. We also applied this modified method to survey the contents of CO in tuna, yellowtail, young yellowtail, and tilapia. As a result, the modified method was found to be more suitable for CO quantification than the official method. An inter-laboratory study by 4 laboratories confirmed that the CO content of many samples of tilapia exceeded the regulation value, apparently due to the higher recovery of CO, compared to the official method. Therefore, it was suggested that the regulation value in the case of tilapia should be changed if this method is introduced as an official method.     

Structural and Textural Quality of Kinu-Tofu Frozen-then-Thawed at High-Pressure

To determine effects of high-pressure thawing on quality of high-pressure frozen tofu, kinu-tofu (soybean curd) was frozen 90 min at ca ?20°C at 100 MPa (ice I), 200 MPa (liquid phase), 340 MPa (ice III), 400, 500 or 600 MPa (ice V), then thawed at the same pressure. Texture and structure of this tofu (D) were compared with high-pressure-frozen tofu thawed at atmospheric pressure (A: 90 min frozen; B: 90 min frozen then 2 days at ?30°C; C: 160 min frozen). When tofu was frozen at 200- 500 MPa, ice crystals were largest to smallest in B > A and C > D; pore size of D was the same as untreated tofu. Results indicated ice crystals never grew when frozen at 200–500 MPa. Growth occurred during reduction of pressure at ca ?20°C, frozen storage or while thawing at atmospheric pressure due to phase transition.     

Effect of hygrothermal conditioning on compressive strength after impact in carbon fiber/epoxy composites

Carbon fiber-reinforced polymers have been widely applied in structural parts and components in several sectors, in addition to being constantly used in environments with the presence of humidity and high temperatures, which can affect their density, hardness, and rigidity. In this work, the influence of hydrothermal conditioning on carbon fiber (CF)/epoxy composites was investigated using three types of epoxy resin and two different CF fabric reinforcements, that is, plain weave and eight harness satin (8HS) arrangements. The CF/epoxy composites were subjected to compression after impact (CAI) test by 28 and 40 J energy and then exposed to hydrothermal conditioning for 8 weeks. After the CAI tests, the visual analysis of all composites presented microbuckling mechanisms. The composites tested with 40 J energy absorbed only 2% more moisture compared with the other composites, nonimpacted, and tested with 28 J, indicating that the impact damage did not cause delamination between the layers of the composites, which could facilitate the absorption of water. All composites analyzed showed resistance to CAI even after exposure to humidity, with decreases ranging from 2.8% to 23.8% about the unconditioned specimens. The decrease in CAI also shows the influence of the type of epoxy matrix and the arrangement of the CF in fabrics.     

Application of liquid chromatography-nuclear magnetic resonance spectroscopy for the identification of ethyldimethylpyrazine, a food flavouring agent

The application of liquid chromatography-nuclear magnetic resonance spectroscopy (LC-NMR) for the direct identification of ethyldimethylpyrazine, a food flavouring agent, has been studied. The commercial product is a mixture of two regio-isomers, 2-ethyl-3,5-dimethylpyrazine (1) and 2-ethyl-3,6-dimethylpyrazine (2); however, the exact composition of the mixture is unknown. Structural characterization by LC-MS and GC-MS was not possible because both regio-isomers yield the same molecular related ion and ion fragmentation. To rapidly identify the two regio-isomers, the product was analyzed by LC-NMR with on-flow and fraction loop modes. From the results, the structure elucidations of the two regio-isomers could be carried out without the need to isolate the isomers by the usual procedures.     

High precision in Raman frequency achieved using real-time calibration with a neon emission line: application to three-dimensional stress mapping observations

A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm(-1) when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm(-1). The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved.     

Analysis of Pseudo-polymorphism Conversion of Theophylline During Wet Granulation and Drying Processes and Effect of Binder on Dehydration and Amorphization

We conducted a time-course analysis of the pseudo-polymorphism conversion (i.e., the hydration and dehydration) of the xanthine-related compound theophylline during wet granulation and drying processes, using terahertz spectroscopy. We also investigated the amorphization mechanism of theophylline hydrate during a drying process in a vacuum using terahertz, mid-infrared (mid-IR), and near-infrared (near-IR) spectroscopy. After a high-shear granulation process using a mixture of theophylline, hydroxypropyl cellulose (HPC), and water, the terahertz spectrum (which was similar to that of an anhydride) was changed to a spectrum that was quite similar to that of a monohydrate. This result suggests that (1) an anhydride was converted to a monohydrate during the wet granulation process and (2) the spectrum was changed to the original waveform after the drying process with heat. This phenomenon indicates that the theophylline monohydrate was reconverted to an anhydride during the drying process. When wet granules were dried in a vacuum, the terahertz absorption lessened and finally disappeared with the passage of time, suggesting that the theophylline monohydrate in the granules was converted to an amorphous state. During the drying process with heat, the dehydration progressed temperature dependently regardless of the presence/absence of HPC. In addition, the reconversion from a monohydrate to an anhydride was completed concurrently with the completion of dehydration. The conversion rate of theophylline from a monohydrate to an amorphous form in granules (with HPC) was faster than that without HPC. This observation suggests that HPC promotes the amorphization of theophylline.     

日本历史性城市公园的角色和可持续性发展——以东京日比谷公园为例

有东京中央公园之称的日比谷公园是日本近代公园的鼻祖,至今已有100多年的发展历史。通过历史资料梳理和实地采访,以日比谷公园为例,探讨日本历史性城市公园在其百年发展过程中作为重要城市公共空间的现实作用,以及在可持续发展范畴下对城市公园发展的启示。研究认为,作为城市公共基础设施,城市公园在社会、生活、防灾、生态结构等方面承担了补充和完善城市功能的责任;作为城市历史文化和地域性传承的重要载体,对于城市公园的评价方式和保护制度是影响城市公园可持续发展的重要因素。     

Risk evaluation for staphylococcal food poisoning in processed milk produced with skim milk powder

The growth of S. aureus and the production of staphylococcal enterotoxin A (SEA) in skim milk concentrates stored at inappropriate temperatures in a recovery milk tank (tank for excess concentrated skim milk) used in the manufacture of skimmed milk powder were investigated. Also, it was estimated if a possible outbreak of food poisoning would occur if the contaminated skimmed milk powder was used in the manufacture of processed milk. Skim milk concentrates with milk solid content of 15, 25, and 35% were inoculated with S. aureus at 1-2 log CFU/ml and incubated at 15, 25, or 35 degrees C for 0 to 24 h with or without shaking. Bacterial growth and the level of SEA production were measured. At 35 degrees C with shaking, there was a significant difference (p<0.05) in one way layout analysis of variance, and it was demonstrated that the growth of S. aureus and SEA production could be milk solid content-dependent. Shaking accelerated the growth of S. aureus and SEA production at 35 degrees C. Generally, skim milk powder is produced by mixing a set percentage of skim milk concentrates (recovery milk) from the recovery milk tank into raw milk. If recovery milk contaminated with S. aureus at levels of 1-2 log CFU/ml is kept at 15 to 35 degrees C due to a power failure, it was estimated that processed milk consumption of 670-1200 ml, 420-1500 ml and 18-83 ml would trigger the onset of food poisoning symptoms when skim milk concentrates (recovery milk) are stored at 25 degrees C for 24 h, 35 degrees C for 10 h, and 35 degrees C for 24 h, respectively, during the production of the skim milk powder. Based on these consumption levels, it was concluded that, if recovery milk cannot be refrigerated and is stored at room temperature (25 to 35 degrees C), it must be used within 8 h and preferably within 6 h.