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The volatile sulfur components produced by boiling soybean meal hydrolyzates (AMINOSAN-EKI) have been identified as dimethyl sulfide and hydrogen sulfide. No mercaptan or disulfides were detected.The main precursor of dimethyl sulfide is supposed to be methionine methylsulfonium compound derived from methionine and pectin substances (–COOCH3) during the hydrolysis of soybean meal by hydrochloric acid. 相似文献
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Yataro Obata Haruo Tanaka Yoshinori Ishikawa 《Bioscience, biotechnology, and biochemistry》2013,77(2):104-110
The recent findings1~3) that prenylmercaptan (3-methyl-2-butene-1-thiol) is the major component of the sunlight flavor of beer has led us to investigate the pathway of its evolution. S-Prenyl-l-cysteine, S-(3-methyl-2-butenyl)-l-cysteine, was synthesized according to the general outline of A. Stoll et al.4) from l-cyteine and prenylbromide, since it was considered as one of the precursors of the sunlight flavor of beer. S-Prenyl-l-cysteine was a colorless and odorless crystal, but this compound generated prenylmercaptan when the aqueous solution was exposed to sunlight. The addition of a small amount of riboflavin to the solution as a photosensitizer increased the mercaptan evolution. Prenylmercaptan formed by sunlight was isolated as its 2,4-dinitrophenyl derivative and identified by the comparison of melting point, chromatographic behavior and infrared spectrum with an authentic sample and by its elemental analysis. 相似文献
36.
Junya Mizutani Yataro Obata Yoshinori Ishikawa 《Bioscience, biotechnology, and biochemistry》2013,77(4):382-385
Cysteine-aldehyde compounds were prepared by the reactions of l-cysteine with formaldehyde, acetaldehyde, n-butyraldehyde, benzaldehyde and furfural in 50% ethanol solutions. Hydrogen sulfide and ammonia liberated from cysteine-aldehyde compounds in heated aqueous solutions (oil bath : 120°C) were determined. Although thiazolidine derivatives were stable generally in boiling aqueous solution, l-cysteine-furfural compound was unstable and a large amount of hydrogen sulfide compared with other compounds was released. 相似文献
37.
By using the multiple ascent technique, the authors have resolved the first several oligosaccharides of the product of initial stage of potato phosphorylase action in both the absence and the presence of beet-saponin with maltotriose as primer. The resolved chromatogram was sprayed with a mixture of G-1-P and phosphorylase, followed by spraying with iodine solution to locate the spots in which starch synthesis occurred.Multi-chain mechanism of amylose formation from maltotriose and the suppression of lengthening of amylose chain by beet-saponin in the lag stage of enzyme action could be shown on paper chromatogram. No saccharides other than amylose series were recognized in the case of phosphorylase inhibition by beet-saponin. 相似文献
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The aqueous solutions of 2-alkyl-thiazolidine-4-carboxylic acids and mercaptals of l-cysteine were exposed to sunlight in the presence of a small amount of riboflavin. Hydrogen sulfide, ammonia, carbon dioxide and carbonyl compounds were the photolysis products.As for the carbonyl compounds, formaldehyde and acetaldehyde were identified from thiazolidine-4-carboxylic acid and djenkolic acid, acetaldehyde from 2-methyl-thiazolidine-4-carboxylic acid and l-cysteine-mercaptal of acetaldehyde, and acetaldehyde and n-butyraldehyde from 2-n-propyl-thiazolidine-4-carboxylic acid and l-cysteine-mercaptal of n-butyraldehyde. 相似文献
39.
Hiroyuki Nishimura Akio Asahi Kazuya Fujiwara Junya Mizutani Yataro Obata 《Bioscience, biotechnology, and biochemistry》2013,77(12):1831-1835
The effect of γ-irradiation on the flavor of Onions (Senshu Yellow) associated with sprout-inhibition has been investigated. The relative amounts of propionaldehyde, n-propyl mercaptan and di-n-propyl disulfide in onions stored for 0, 5, 10, 20 and 30 days, respectively, after irradiation were estimated by measurement of peak areas of gas chromatograms. It was observed that the lachrymatory character and the pungent flavor had been decreased by γ-irradiation (remarkably at 70 and 700 Krads). In this connection, the amounts of propionaldehyde and di-n-propyl disulfide were decreased with increasing radiation dose and storage period at room temperature (20 to 25°C) and at low temperature (4°C). Moreover, it was observed that the sweetness had been decreased by γ-irradiation, but the amount of n-propyl mercaptan was increased with radiation dose and storage period. Therefore it seems that there is no correlation between the sweetness of onion and the amount of n-propyl mercaptan. 相似文献
40.
Sadao Sakamura Hiroshi Niki Yataro Obata Ryutaro Sakai Takeshi Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(5):698-703
In the course of phytopathological studies, it has been observed that phyllosticta sp. produces a toxic compound causing wilting and simultaneous dark coloration of the clover leaf. A toxin, herein refered to as phyllosinol (mp 76~77°C) was isolated in a crystalline state from the pure culture and it was proved to be the principal toxic metabolite of the fungus. Although the melting point of phyllosinol differed significantly from that reported for epoxydon (40~45°C), the structural evidence deduced from spectrometric and chemical methods indicates that phyllosinol is substantially identical with epoxydon even in stereo-isomeric considerations. In the red clover leaf test 10 ppm phyllosinol showed the wilting effect. 相似文献