Studies on the Flavors of Roast Barley (Mugi-cha)

Seven weakly acidic compounds were newly detected as flavor components of roast barley by using column and gas-liquid chromatographies. These compounds were characterized and identified by MS, IR, UV and NMR spectroscopies and the mixed melting point test.

These are 5-hydroxymaltol, maltol, 5-methylcyclopent-2-en-2-ol-1-one, phenol, m-cresol, pyrocatechol, resorcinol and an unidentified compound (MW 128). Maltol, 5-methylcyclopent-2-en-2-ol-1-one and 5-hydroxymaltol have so-called “sugary flavor,” and these compounds appear to concern with the sweet fragrant flavor of roast barley together with vanillin previously identified.

Phenol, m-cresol, pyrocatechol and resorcinol which have a strong characteristic odor are supposed to concern with the smoky flavor of roast barley.     

Volatile Flavor Compounds of Boiled Buckwheat Flour

Volatile flavor compounds of boiled buckwheat flour were collected using a Likens and Nickerson apparatus type and were fractionated into acidic, weak acidic, basic and neutral fractions. The neutral fraction was further fractionated by silica gel column chromatography. All fractions were analyzed by gas chromatography and gas chromatography-mass spectrometry.

Two hundred and nine compounds were thus identified. Among them, 168 were newly identified as volatile flavor compounds of buckwheat flour; special note is made of 2-(1′-ethoxyethyl)pyrazine and 2-(1′-ethoxyethyl)-5-methylpyrazine being found which are compounds previously unreported in any literature.     

Studies on the Browning of Kori-tofu

Properties of ether extract of browned Kori-tofu were investigated. More than half amount of neutral glycerides of Kori-tofu changed into weak-acidic substances after browning, in which most of extracted brown pigments were contained. These weak-acidic substances showed properties of carbonyl and reductone, and mainly contained glycerides, whose constitutional fatty acids were palmitic, oleic, and linoleic acids as well as a little amount of azelaic and stearic acids.

From the ether extract of browned Kori-tofu were isolated and identified azelaic acid and carbonyls. The carbonyls identified were benzaldehyde, methylethylketone, crotonal, acetaldehyde, α-ketoaldehydes of C₂, C₃, C₄, C₅, C₇ and C₉, and hexane-2,3-dione. Two nitrogeneous carbonyl compounds were isolated. Formation mechanisms of these compounds and their roles in browning of Kori-tofu were discussed.     

Volatile Flavor Components of Dried Bonito (Katsuobushi). I. On Basic,Acidic and Weak Acidic Fractions

The aqueous extract of dried bonito (Katsuobushi) was distilled by using a thin film evaporator. The resulting distillate was extracted with diethyl ether, and the extract was separated into basic, acidic, weak acidic, and neutral fractions.

The basic, acidic, and weak acidic fractions were analyzed by gas chromatography and gas chromatography-mass spectrometry.

Seventy-four compounds, including 24 acids, 24 phenols, 8 pyridines, 12 pyrazines, 3 thiazoles, and 3 other compounds were identified. Thirty-six of these compounds were newly identified as volatile flavor compounds of Katsuobushi.     

欧洲李种子的化学成分研究

利用溶剂萃取和色谱分离手段,从蔷薇科植物欧洲李(Prunus domestica L.)种子中得到6个化合物。通过光谱分析,分别鉴定为松柏醛(1)、东莨菪亭(2)、(-)-二氢脱氢二松柏醇(3)、(-)-榕醛(4)、(E)-3,3’-二甲氧基-4,4’-二羟基茋(5)和5-羟甲基糠醛(6)。这些化合物均系首次从欧洲李种子中分离得到。     

Fractionation and Identification of Volatile Compounds in Patis,a Philippine Fish Sauce

Commercial Philippine fish sauce (Patis) was steam-distilled and the distillate was fractionated into four fractions, neutral, basic, acidic and phenolic and each fraction was analyzed using gas chromatography and gas chromatography-mass spectrometry.

As a result of this study, a total of 66 compounds were identified in Patis, 14 of which were only a tentative identification. Out of these 66 identified compounds, 40 identified compounds have not been reported in previous studies on fish sauces. These identified compounds include 19 acids, 14 alcohols, 12 nitrogen containing compounds, 5 esters, 3 sulfur containing compounds, 1 phenol, 3 carbonyls, 7 hydrocarbons and 2 others. In the acidic fraction, 5 acids were considered major constituents which accounted for about 98% of the total acids. n-Butanoic acid was found to be the most abundant accounting for about 50% of the total acids.     

An anti-HBV anthraquinone from aciduric fungus Penicillium sp. OUCMDZ-4736 under low pH stress

To obtain new bioactive natural products, the effect of acidic stress on the metabolites of an aciduric fungus was investigated. This fungus, Penicillium sp. OUCMDZ-4736, which was isolated from the sediment around roots of mangrove (Acanthus ilicifolius), produced different compounds and higher yields under pH 2.5 than under neutral conditions. Using spectroscopic analyses and calculations, three new anthraquinone derivatives (1–3) were isolated and identified from the acidic fermentation broth (pH 2.5) of OUCMDZ-4736. Compound 1 showed much stronger anti-hepatitis B virus activity than that of the positive control, lamivudine, strongly inhibiting HBsAg and HBeAg secretion from HepG2.2.15 cells. These results show that extremophiles are a valuable resource of bioactive compounds, and that pH regulation is an effective strategy to induce metabolite production in aciduric fungi.

     

Metabolism of isoeugenol via isoeugenol-diol by a newly isolated strain of Bacillus subtilis HS8

A bacterium designated as HS8 was newly isolated from soil based on its ability to degrade isoeugenol. The strain was identified as Bacillus subtilis according to its 16S rDNA sequence analysis and biochemical characteristics. The metabolic pathway for the degradation of isoeugenol was examined. Isoeugenol-diol, for the first time, was detected as an intermediate from isoeugenol to vanillin by a bacterial strain. Isoeugenol was converted to vanillin via isoeugenol-diol, and vanillin was then metabolized via vanillic acid to guaiacol by strain HS8. These metabolites, vanillin, vanillic acid, and guaiacol, are all valuable aromatic compounds in flavor production. At the same time, the bipolymerization of isoeugenol was observed, which produced dehydrodiisoeugenol and decreased the vanillin yield. High level of vanillic acid decarboxylase activity was detected in cell-free extract. These findings provided a detailed profile of isoeugenol metabolism by a B. subtilis strain for the first time, which would improve the production of valuable aromatic compounds by biotechnology.     

Flavor of Black Tea

Intermediate and high boiling neutral compounds in the aroma concentrate from black tea were isolated by fractional distillation, silica-gel column chromatography and gas chromatography.

Identification of the compounds was verified by the agreement of IR and mass spectra as well as gas chromatographic data with those of authentic compounds.

Eleven compounds; α-muurolene, δ-cadinene, furfuryl alcohol, methyl phenyl carbinol, cadinenol, geranial, pyrrole-2-aldehyde, benzyl formate, phenylethyl formate, cis-3-hexenyl benzoate and indole, were newly identified as constituents of black tea aroma and ten known components; α-terpineol, 3, 7-dimethyl-l, 5, 7-octatrien-3-ol, trans, trans-2, 4-decadienal, 2-phenyl-2-butenal, α- and β-ionone, cis-jasmone, theaspirone, lactone of 2-hydroxy-2, 6, 6-trimethylcyclohexylidene-l-acetic acid and phenylacetonitrile were confirmed. The geometric structure of theaspirone in tea aroma was determined as the cis-form.     

Volatile Flavor Components of Dried Bonito (Katsuobushi) II. From Neutral Fraction

The aqueous extract of dried bonito (Katsuobushi) was distilled under reduced pressure. The resulting distillate with diethyl ether and the extract was separated into acidic, phenolic, basic and neutral fractions. The neutral fraction was further fractionated into ten sub-fractions by silica gel column chromatography. All these sub-fractions were analyzed by gas chromatography and gas chromatography-mass spectrometry.

One hundred and sixty-five compounds were identified and 12 compounds were tentatively identified from the neutral fraction. Among them, 111 compounds were newly identified as flavor components of Katsuobushi.     

The Incorporation of Ciliatine (2-Aminoethylphosphonic Acid) into Lipids of the Rat Liver

Four alcohols, 1-penten-3-ol, n-amylalcohol, trans-2-hexenol and one of the linalool oxides, were newly identified as the components of carbonyl-free neutral fraction of the essential oil of black tea.

On the gas chromatogram of carbonyl fraction three unknown peaks were identified with those of n-valeraldehyde, n-heptanal and trans-2-octenal.

From these results almost all main components of carbonyl and carbonyl free fractions were clarified.

Flavor change during the manufacture of black tea was investigated by gas chromatography. During withering, hexylalcohol, nerol, trans-2-hexenoic acid, trans-2-heхenol, linalool oxide (cis, furanoid), n-valeraldehyde, capronaldehyde, n-heptanal, trans-2-hexenal, trans-2-octenal, benzaldehyde, phenylacetaldehyde, n-butyric, isovaleric, n-caproic, cis-3-hexenoic and salicylic acids and o-cresol were increased, especially the former three greatly increased, while cis-2-pentenol, linalool, geraniol, benzylalcohol, phenylethanol and acetic acid diminished markedly. In the process of fermentation almost all constituents increased, especially, 1-penten-3-ol, cis-2-pentenol, benzylalcohol, trans-2-hexenal, benzaldehyde, n-caproic, cis-3-hexenoic and salicylic acids were remarkable.

On firing, most alcohols, carbonyl and phenolic compounds decreased remarkably whereas acetic, propionic and isobutyric acids greatly increased.     

Studies on Kojic Acid Metabolism by Microorganisms

An enzyme, comenic aldehyde dehydrogenase, which catalyzes the oxidation of comenic aldehyde to comenic acid was partially purified from cell extract of Arthrobacter ureafaciens K-1.

The enzyme was purified 31-fold at Sephadex G-100 filtration step, 112-fold at DEAE-Sephadex A-50 fractionation step, and recovery of the activity was 73.3% and 38.5% respectively.

NADP and magnesium ion were essential for the oxidation. The enzyme shows optimum activity at pH 7.8. Enzyme activity was extremely sensitive to sulfhydryl reagents such as p-chloromercuribenzoate and monoiodoacetate. l-Cysteine or dithiothreitol protected the enzyme from p-chloromercuribenzoate inhibition. Carbonyl reagents, such as hydroxylamine and semicarbazide, inhibit the enzyme reaction by formation of addition compounds between carbonyl reagents and aldehyde group of the substrate. The enzyme was completely inactivated after heating for 5 min at 40°C The Km for 5-methoxy comenic aldehyde is 2.5×10^?6 m, and for NADP is 0.4×1O^?6 m. The reaction product, 5-methoxy comenic acid was identified by paperchromatography. The characterization of the enzyme has been carried out by using 5-methoxy comenic aldehyde as the substrate in stead of comenic aldehyde.     

Inhibitory effect of the compounds from the water extract of Curcuma longa on the production of PGE2 and NO in a macrophage cell line stimulated by LPS

ABSTRACT

We wished to search for the compounds contributing to the anti-inflammatory effects of the water extract of Curcuma longa (WEC). WEC was fractioned and the fractions were evaluated with regard to their inhibitory effect on the production of nitric oxide (NO) from the macrophage cell line stimulated by lipopolysaccharide. Compounds in the active fractions were isolated and identified. One isolated compound was identified as new: (6S)-2-methyl-5-hydroxy-6-(3-hydroxy-4-methylphenyl)-2-heptene-4-one (1). Four isolated compounds were identified as known: (6S)-2-methyl-6-(4-hydroxyphenyl)-2-heptene-4-one (4), bisabolone-4-one (5), curcumenone (6), and turmeronol A (8). Three isolated compounds were not identified their stereostructures but their planar structures: 2-methyl-6-(4-hydroxymethyl-phenyl)-2-heptene-4-one (2), 2-methyl-6-(2,3-epoxy-4-methyl-4-cyclohexene)-2-heptene (3), and 4-methylene-5-hydroxybisabola-2,10-diene-9-one (7). Compounds 1, 4, 7 and 8 inhibited production of prostaglandin E2 and NO. Others inhibited NO production only. These results (at least in part) show the active compounds contributing to the anti-inflammatory effects of WEC, and may be useful for elucidating its various beneficial physiologic effects.     

Isolation and Identification of the Characteristic Sweet-aroma Compounds in Refinery Final Molasses

The characteristic sweet-aroma components in refinery final molasses were isolated by using a combination of sensory evaluation, column chromatography and gas chromatography, and were identified by infrared spectrometry, mass spectrometry and color reactions. Identified were ethyl n-hexanoate, ethyl phenylacetate, phenylacetic acid, n-butyl benzoate, isopropyl benzoate, l(+)-pantolactone, benzoic acid, o-toluic acid, m-toluic acid, β-phenylpropionic acid, succinic anhydride, maltol, isomaltol, and 2-methyl-5-hydroxy-6-ethyl-γ-pyrone.

The aroma of the mixture of these compounds and vanillin and vanillic acid was similar to that of refinery molasses by sensory evaluation. The results indicate that these compounds are important in producing of sweet molasses aroma.     

Fermentation of corn fiber hydrolysate to lactic acid by the moderate thermophile <Emphasis Type="Italic">Bacillus coagulans</Emphasis>

A strain of Bacillus coagulans that converted mixed sugars of glucose, xylose, and arabinose to l-lactic acid with 85% yield at 50°C was isolated from composted dairy manure. The strain was tolerant to aldehyde growth inhibitors at 2.5 g furfural/l, 2.5 g 5-hydroxymethylfurfural/l, 2.5 g vanillin/l, and 1.2 g p-hydroxybenzaldehyde/l. In a simultaneous saccharification and fermentation process, the strain converted a dilute-acid hydrolysate of 100 g corn fiber/l to 39 g lactic acid/l in 72 h at 50°C. Because of its inhibitor tolerance and ability to fully utilize pentose sugars, this strain has potential to be developed as a biocatalyst for the conversion of agricultural residues into valuable chemicals.     

Studies on the Hypertrophic Disease of Cherry (Genus Prunus), So-called “Witch’s Broom” Caused by Taphrina wiesneri

Metabolites of Taphrina wiesneri (Rath.) Mix. were examined. Brassicasterol, stearic acid, and p-hydroxyphenylacetic acid were isolated in crystalline form. p-Hydroxybenzoic acid and vanillic acid were identified by paper chromatography and UV measurement. Palmitic acid was identified by gas-chromatography. The fungus produced usually these compounds on any one of four kinds of medium used. p-Hydroxyphenylacetic acid promoted germination of rape seeds at the concentration of 20 ppm in water and showed inhibition at 250 ppm.

Phenolic acids and their related compounds in Japanese flowering cherry leaves infected by Taphrina wiesneri were examined. In the acidic and neutral extracts of infected cherry leaves (I), eighteen compounds positive to diazotized sulfanilic acid and two fluorescent compounds were detected by paper chromatography. Of these compounds, coumarin, 3, 4-dihydrocoumarin, melilotic acid, o- and p-coumaric acids, p-hydroxybenzoic melilotic acid, ferulic acid and caffeic acid were identified. Melilotic acid and coumarin were obtained in crystalline form. The amount of melilotic acid in I was higher than that in healthy leaves independent of sample source, although increased with the growth of cherry leaves.     

Action of Poly-l-malic Acid on Various Proteolytic Enzymes

The steam volatile neutral fraction of tobacco smoke condensates was separated into n-hexane, nitromethane and 1:4 water-methanol soluble fractions by solvent partition.

2.methyl-4-hydroxy-2-hexenoic acid lactone, dihydroactinidiolide and phthalide were isolated from the 1:4 water-methanol soluble fraction, the highly polar portion of the steam volatile neutral fraction was designated as the M fraction.

By continuing analysis of the M fraction from a previous paper, benzyl alcohol, phenyl-ethyl alcohol, pyrrole-2-aldehyde, α-pyrrylmethylketone, α-pyrrylethylketone, α-carbomethoxypyrrole, pyrrole-2-carbonitrile, methyl-pyrrole-2-carbonitrile, 3-methyl-, 3-ethyl-, 3-n-propyl-, 2,3-dimethyl-, 2-ethyl-3-methyl-2-cyclopentene-1-one and norsolanadione were identified.

Identification of the compounds was based on the spectroscopic method (IR, MS, UV and GC-MS) and gas chromatographic analysis.     

Flavor of Black Tea

The neutral fraction of the essential oils from three kinds of black tea (same samples as described in the previous paper,¹⁾ i.e., Assam, Shan and Benihomare) was separated into carbonyl and carbonyl-free fractions and analysed by gas chromatography. On the basis of relative retentions and aroma of effluents with the references of the chromatographic data obtained by the previous works,^2–4) the major alcohols were found to be cis-2-pentenol, n-hexanol, cis-3-hexen-1-ol, three isomers of linalooloxide, linalool, nerol, geraniol, benzylalcohol, and phenylethylalcohol. In the carbonyl fraction, phenylacetaldehyde was newly identified, and besides it, the presence of iso- and n-butyr-, iso- and n-valer- aldehyde, methylethylketone, trans-2-hexenal, benzaldehyde were recognized. There were no differences in the components among three kinds of black tea, but the relative quantity of each component in the essential oil was different among three varieties.     

Polysaccharides and Bioactive Phenolics from Aconitum septentrionale Roots

Aconitum septentrionale is known to contain toxic diterpene alkaloids, while other bioactive compounds in the plant remain unclear. The aim of this study was to explore the phenolic compounds and polysaccharides from the water extract of A. septentrionale roots. Fifteen phenolic compounds were isolated and identified by NMR and MS, including fourteen known and one new dianthramide glucoside (2-[[2-(β-D-glucopyranosyloxy)-5-hydroxybenzoyl]amino]-4,5-dihydroxybenzoic acid methyl ester, 14 ). One neutral (complex of glucans with minor amounts of mannans) and two acidic polysaccharide fractions (complexes of pectic polysaccharides and glucans) were also obtained. Hydroxytyrosol ( 1 ), hydroxytyrosol-1-O-β-glucoside ( 2 ) and bracteanolide A ( 7 ) inhibited the release of nitric oxide by dendritic cells. Magnoflorine ( 8 ) and 2-[[2-(β-D-glucopyranosyloxy)-5-hydroxybenzoyl]amino]-5-hydroxybenzoic acid methyl ester ( 12 ) inhibited 15-lipoxygenase, and bracteanolide A ( 7 ) was a moderate inhibitor of xanthine oxidase. This study is the first to describe the diversity of phenolics and polysaccharides from A. septentrionale and their anti-inflammatory and anti-oxidant activities.     

Transportation mechanism for vanillin uptake through fungal plasma membrane

Protoplasts of the basidiomycete, Fomitopsis palustris (formerly Tyromyces palustris), were utilized to study a function of the fungal plasma membrane. Fungal protoplasts exhibited metabolic activities as seen with intact mycelial cells. Furthermore, the uptake of certain compounds into the protoplast cells was quantitatively observed by using non-radioactive compounds. Vanillin was converted to vanillyl alcohol and vanillic acid as major products and to protocatechuic acid and 1,2,4-trihydroxybenzene as trace products by protoplasts prepared from F. palustris. Extracellular culture medium showed no activity responsible for the redox reactions of vanillin. Only vanillic acid was detected in the intracellular fraction of protoplasts. However, the addition of disulfiram, an aldehyde dehydrogenase inhibitor, caused an intracellular accumulation of vanillin, strongly suggesting that vanillin is taken up by the cell, followed by oxidation to vanillic acid. The addition of carbonylcyanide m-chlorophenylhydrazone, which dissipates the pH gradient across the plasma membrane, inhibited the uptake of either vanillin or vanillic acid into the cell. Thus, the fungus seems to possess transporter devices for both vanillin and vanillic acid for their uptake. Since vanillyl alcohol was only observed extracellularly, the reduction of vanillin was thought to be catalyzed by a membrane system.