Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.
Twelve strains of moderately thermophilic bacteria were isolated from saline hot springs (55°C, pH 8.3) located in Odaito, Hokkaido, Japan. Based on their 16S rRNA gene sequences, all the strains were closely related phylogenetically each other, indicating that the strains belong to a single species. However, maximal growth temperature and enzymatic characteristics of individual strains were slightly different each other. Some of them grew well at 55°C but others did not. The β-galactosidase activity was also different among the strains. Therefore, the representative strains BEK6 and BEK11 were chosen from individual phenotype groups, and were used for further characterization. The nucleotide sequence of full-length 16S rRNA genes of the representative strains showed 96.6% similarity with Bacillus alveayuensis indicating that the strains belong to a novel species of the genus Bacillus. The cells were Gram positive, and showed both catalase and oxidase activities. The optimal growth temperature and pH of strain BEK6 and BEK11 were around 50°C and 7-8, respectively. They were able to grow in the medium containing 10% NaCl in contrast to B. alveayuensis which can grow in the medium with up to 4% NaCl. The strain BEK11 showed relatively strong protease and amylase activities implying the potential industrial uses of these enzymes under the saline condition.
The relation between the composition of compounds induced from ATP and the freshness of raw fish was investigated. For the analyses of hypoxanthine, Hyp and IMP by using 5'-nucleotidase, nucleoside phosphorylase and xanthine oxidase were employed. The assay method was based on the separation of adenine, hypoxanthine, adenosine, inosine and nucleotides with ion exchage resin (Dowex 1×2 chloride type). The analysis of these substances in Canned fishes can be adopted as an index of their quality.
The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 μg, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100).
A sensitive and simple separation method for methylguanidine (MG) and agmatine (AGM) in various foods by high performance liquid chromatography with a fluorescence detector is described. Food samples were homogenized in 4% trichloroacetic acid solution and filtered. The guanidino compounds were extracted with n-butanol from the filtrate under alkaline conditions and re-extracted with 1N hydrochloric acid. They were converted into fluorescent derivatives by reaction with benzoin under alkaline conditions. Guanidino compounds were separated and determined on a Nucleosil 5C18 column with methanol -0.5M Tris-Hydrochloric acid Buffer (pH 8.6) (8:2) as the mobile phase. The recoveries of MG and AGM added to smoked dried fish and wiener sausage were 85.0% (MG), 82.5% (AGM) and 88.2% (MG), 82.3% (AGM), respectively. The limits of determination were 0.1ppm for MG and 0.5ppm for AGM. Smoked-dried bonito (Katsuo-bushi) contained 12 to 238ppm of MG. The amounts of MG and AGM determined in almost all samples were small or below the detection limits.
A rapid and simple method was developed for simultaneous determination of methyl, ethyl, isopropyl, npropyl, isobuthyl and n-buthyl p-hydroxybenzoic acid esters (PHBA-Es) in laver by HPLC. Six PHBA-Es were extracted from laver with n-hexane-ethyl acetate (1:1) by shaking. The extract was evaporated. The residue was dissolved in methyl alcohol and determined by HPLC. Recoveries of six PHBA-Es spiked in laver were 93.6-101.2% at the level of 2 micrograms/g.
Oysters stored at -20°C immediately after husking were used. Samples of oysters were taken at intervals during the thawing process at 5°C for 72 hours to be extracted with perchloric acid. The amounts of nucleotides and the related compounds in thawed oysters were determined by the ion exchange chromatography and enzymatic assay. The rapid increse of the content of 5'-IMP was observed during thawing probably due to the deamination of 5'-AMP in fresh oysters.It was found that the concentration of IMP is very important as the index of the quality of oyster meats because IMP is the major nucleotide and the flavor enhancing constituent in fresh oysters.The amount of IMP reached the maximum level (0.28μ mole/g) at 5°C after 6 hours thawing.
Twenty compounds were isolated from the roots of Rubia tinctorum which are used as a commercial source of madder color. Among these compounds, mollugin (1), 1-hydroxy-2-methylanthraquinone (2), 2-ethoxymethylanthraquinone(11), rubiadin (13), 1,3-dihydroxyanthraqunone (14), 7-hydroxy-2-methylanthraquinone (16), lucidin (17), 1-methoxymethylanthraquinone (18) and lucidin-3-O-primeveroside (19) showed mutagenicity with Salmonella typhimurium TA 100 and/or TA 98. Since the mutagenic compounds isolated are anthraquinone derivatives with the exception of compound 1, structure-mutagenicity relationships of the anthraquinones were also studied. The results suggested that the greatest activity is exhibited by 1,3-dihydroxyanthraquinones possessing methyl or hydroxylmethyl group on carbon 2.
