A New Aroma-Bearing Substance from Shiitake, an Edible Mushroom

SUMMARY— Investigations on the physico-chemical properties and a sensory evaluation as a component of Shiitake flavor were carried out with lenthionine, a substance which was isolated from dried Shiitake mushroom. Lenthionine is practically insoluble in water but soluble in non-polar solvents. Its stability in an aqueous solution changes greatly with the pH of the solution.
Lenthionine was identified as a significant component in the aroma of Shiitake mushroom and its detectable threshold level is at a concentration between 0.27 and 0.53 porn in water. This new aroma-bearing substance will be used as a flavor additive in various foods.     

Nitric Oxide Complex of Iron(II) Myoglobin Converted from Metmyoglobin by Staphylococcus xylosus

With Staphylococcus xylosus FAX-1, metmyoglobin in MRS broth (pH 5.8) was found to undergo conversion to hexacoordinate nitric oxide (NO) complex of Fe(II) myoglobin. When the pH of the MRS culture containing myoglobin changed from 5.8 to 4.0, it affected the conversion from hexacoordinate to pentacoordinate NO complex of Fe(II) myoglobin. This conversion process was reversible. Salami without nitrite or nitrate addition was prepared by inoculating S. xylosus FAX-1, and pentacoordinate NO complex of Fe(II) myoglobin (nitrosylmyoglobin formed in cured meat) was formed in the salami.     

Mass Production Method for Rice Protein Isolate and Nutritional Evaluation

We developed a method for mass production of rice protein isolate (RPI) and evaluated its nutritional quality in rats. To obtain thick slurry, rice flour was mixed with a 0.6% Termamyl 120L-solution (1:2, w/v) at room temperature (～23°C). The slurry was heated at 97°C for 2 hr with stirring. Gelatinization and liquefaction occurred simultaneously. RPI obtained by filtration and washing with boiling water, was more than 90% pure protein (dry matter basis). It also contained 6.4% dietary fiber, 1.3% ash, and 1.1% carbohydrate. RPI diets (40–50%) allowed the maximum growth in rats comparable to that with 25% casein diet.     

Heat-induced Gelation of Chicken Gizzard Myosin

Chicken gizzard myosin solution formed a gel when heated above 40°C. The rigidity of the gel was constant above 65°C. Maximum pH for gel formation was 5.9 at 0.6M and 5.7 at 0.15M KCl. Higher rigidity of the myosin gel was observed at low ionic strength than at high ionic strength. Rigidities of myosin at 0.6M KCl increased by (mg/mL)^2.5 and at 0.15M (mg/mL)^{1, 4} myosin concentration. The strength of gizzard myosin gels was comparable to that of myosin gels from chicken breast muscle under similar conditions.     

Red Pigment of Parma Ham and Bacterial Influence on its Formation

The red pigment of Parma ham was compared with the myoglobin derivatives present in meat and meat products. Spectral patterns of 75% acetone extracts and electron spin resonance spectra from Parma ham differed from those of the myoglobin derivatives. Staphylococci isolated from Parma ham generated red myoglobin derivative from metmyoglobin. Model fermented sausage prepared by inoculation with the isolates developed a more desirable red color without nitrite or nitrate treatment. The red pigment of Parma ham and the model sausage appeared to be the same myoglobin derivative. The reddening of Parma ham is probably caused by the action of bacteria.     

Boron removal from metallurgical grade silicon by oxidizing refining

A purification process was developed to remove impurity element boron from the metallurgical grade silicon by the electric arc furnace refining. The thermodynamic equilibria calculation and experiment to remove boron in the oxidizing atmosphere were performed and analyzed. Boron is removed as the gaseous species BxOy and BxHzOy in O2 and H2O-O2 atmosphere respectively. The equilibrium pressure of BxHzOy is 105-1010 times that of BxOy. Boron is removed and its content in silicon is reduced from 18×10-6 to 2×10-6 in the Ar-H2O-O2 atmosphere in the electric arc furnace.     

含氢氧化物陶瓷的水分裂与氢发射催化作用之离子束技术研究

Recently,we have proposed a new model of one Wav diffusion for the D-H replacement observed for D-implanted SrCeo.95 Yb0.05O3-δ exposed to air vapor at room temperature:absorption of H+ and adsorption of OH due to dipole induced splitting of H2O* physisorbed at the surface,diffusion of H+ in the bulk and emission of DH molecule due to local molecular recombination of H+ with D implanted in traps and subsequent trapping of H+ in the vacant trap.     

RHYTHMIC AND IRREGULAR MOVEMENT OF THE FIRST MOLAR WHILE EATING FOODS WITH DIFFERENT TEXTURES

The three-dimensional movement of a tooth, any tooth, while naturally eating, was measured by an apparatus developed in our laboratory. The movement of the first molar on the usually used side is reported here. The mastication movements are divided into two parts, namely the rhythmical chewing period during which there are mastication pressure loads on the molar and the irregularly pulsated moving period in preparation for the swallowing followed by the rhythmical one during which there is no more pressure on it. The amplitudes of the up and down movements of the molar are 10–22mm for the rhythmical chewing period which are bigger than those for the irregularly moving period. The rhythmical chewing periods are distributed around 10–40 s depending on 14 kinds of food texture, and also on the size of the food, in a fairly similar manner for the participants. The period is longer for tough foods and bigger samples. The irregularly pulsated moving periods are widely distributed, 2–45s, and depend both on the food texture and on the participant. The irregular moving periods are longer for foods which scatter in the mouth or adhere to the teeth when chewing. The ingestion difficulty of the food was divided into two groups. One is where it is difficult to break down the food with the teeth and the other is where it is difficult to prepare for swallowing.     

High-strain-rate superplasticity in oxide ceramics:a trial of microstructural design based on creep-cavitation mechanisms

From existing knowledge about high-temperature cavitation mechanisms,necessary conditions were discussed for the suppression of cavitation failure during superplastic deformation in ceramic materials.The discussion,where special attention was placed on the relaxation of stress concentrations during grain-boundary sliding and cavity nucleation and growth,leaded to a conclusion that cavitation failure could be retarded by the simultaneous controlling of the initial grain size,the number of residual defects,diffusivity,dynamic grain growth and the homogeneity of microstructure.On the basis of this conclusion,high-strain-rate superplasticity (defined as superplasticity at a strain rate higher than 0.01 s-1) could be intentionally attained in some oxide ceramic materials.This was shown in tetragonal zirconia and composites consisting of zirconia,α-alumina and a spinel phase.