Retort beef aroma that gives preferable properties to canned beef products and its aroma components

The objective of this study is to identify the properties and responsible compounds for the aromatic roast odor (retort beef aroma) that commonly occurs in canned beef products and could contribute to their palatability. The optimal temperature for generating retort beef aroma was 121°C. An untrained panel evaluated both uncured corned beef and canned yamato‐ni beef and found that they had an aroma that was significantly (P < 0.01) similar to the odor of 121°C‐heated beef than 100°C‐heated beef. The panel also noted that the aroma of 121°C‐heated beef tended to be (P < 0.1) preferable than that of 100°C‐heated beef. These results suggest that retort beef aroma is one constituent of palatability in canned beef. GC‐MS (gas chromatography‐mass spectrometry) analysis of the volatile fraction obtained from 100°C‐ and 121°C‐heated beef showed that the amounts of pyrazine, 2‐methylpyrazine and diacetyl were higher in the 121°C‐heated beef than in the 100°C‐heated beef. GC‐sniffing revealed that the odor quality of pyrazines was similar to that of retort beef aroma. Therefore, pyrazines were suggested to be a candidate responsible for the retort beef aroma. Analysis of commercial uncured corned beef and cured corned beef confirmed the presence of pyrazine, 2‐methylpyrazine and 2,6‐dimethylpyrazine.     

Changes of fumonisin production in rice grain during ensiling

We assessed fumonisin production during the ensiling of rice grain. Rice grain was harvested at the full‐ripe stage and prepared as rough rice, crushed rough rice, brown rice or crushed brown rice. Each material was ensiled under six conditions: (1) no fungus, anaerobic; (2) no fungus, aerobic; (3) water added, anaerobic; (4) water and fumonisin‐producing fungus added, anaerobic; (5) water and fumonisin‐producing fungus added, aerobic; or (6) fumonisin‐producing fungus added to autoclaved material, aerobic. After 40 days of ensilage, we analyzed the silage fermentative quality and fumonisin concentration. The fermentative quality of all materials was good in treatments (3) and (4) (pH < 4), reasonable in treatment (5) (pH = 5～6) and unacceptable in treatments (1) and (2) (pH > 6.5). The fumonisin concentration was low in all materials in treatments (1) to (4), slightly increased in the three materials other than rough rice in treatment (5), and enormously increased in all materials in treatment (6). The results indicate that the fumonisin‐producing fungus does not produce fumonisin in anaerobic conditions. It is important that an anaerobic condition be maintained during ensiling in order to reduce the fumonisin content in rice grain silage.     

Isolation and characterization of a phenolic antioxidant from the Pacific oyster (Crassostrea gigas)

Using an oxygen radical absorbance capacity (ORAC) assay, antioxidant activity was detected in the ethanol extract of the Pacific oyster, which was purified by sequential extraction with organic solvents. The ethyl acetate fraction showed the strongest antioxidant activity and was further purified, yielding a single compound [as assessed by thin-layer chromatography (TLC) and reverse-phase high-performance liquid chromatography (HPLC)]. This compound was identified as 3,5-dihydroxy-4-methoxybenzyl alcohol on the basis of (1)H and (13)C nuclear magnetic resonance (NMR), heteronuclear multiple-bond correlation (HMBC), and electrospray ionization-mass spectrometry (ESI-MS) spectral analyses, a conclusion that was confirmed by chemical synthesis. The concentration of the compound was 6.7 mg/100 g of whole oyster meat wet weight. This amphiphilic antioxidant retarded the copper-mediated oxidation of low-density lipoproteins (LDLs) and the generation of thiobarbituric acid reactive substances. Furthermore, the compound showed substantial antioxidant activity using the ORAC and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays compared to natural antioxidants. Although the same compound was previously found in brown algae, its presence in other organisms and antioxidant activity are reported here for the first time.     

Microbial metabolism in reduction process of paddy soils (Part 2)

The previous experiences^1-3) with incubation experiments of the soils under submargd condition indicated that the disappearance of molecular oxygen and nitrates occurred shortly after sub-emerging, and then the reduction of ferric iron proceeded, being followed by the reduction of sulfates and the formation of methane which nre caused by the activities of strict anaerobes. It was suggested from the above fact that the reduction process in the submarged soils was affected mainly by two factors: namely, the amount of reducible ferric iron and the soil organic matters which are avaiable as substrate for microbial metabolism.     

Bacterial canker of Maackia amurensis var. buergeri caused by a putative Pseudomonas syringae

A new disease of Maackia amurensis var. buergeri was recently found on the northern island of Hokkaido, Japan. Affected trees were heavily damaged and had cankers on both trunks and branches. After natural infection, a series of swellings on the bark surface developed longitudinally. These swellings burst and coalesced to become long cankers. It is proposed that the disease be designated ‘bacterial canker of Maackia’. The causal pathogen was isolated and characterized tentatively as Pseudomonas syringae on the basis of laboratory tests. Pathogenicity of the bacterium was confirmed by inoculation into the host.     

Corrosive-wear characteristics of diamond-coated cemented carbide tools

Continuous milling tests with diamond-coated and uncoated cemented carbide tools and polycrystalline diamond tools were carried out on air-dried and wet melapi (Shorea sp.) and western redcedar (Thuja plicata D. Don). These tools were examined for corrosive-wear characteristics of the tool-edge appearance, cutting-edge profile, edge recession, and cutting-power consumption. The tool surfaces were observed with a scanning electron microscope and were analyzed by energy-dispersive X-ray spectroscopy. Based on these examinations, the occurrence of corrosive wear while cutting wet woods was confirmed for the uncoated and polycrystalline diamond tools. In contrast, the coated tools did not exhibit corrosive wear, nor did delamitation or wear of the diamond film occur with any of the work materials. The diamond-coated tools showed high resistance not only to mechanical wear but also to corrosive wear.The results of this work were presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998