The histological structures of the parts of Shiitake mushrooms where we felt firmness by sensory evaluation were observed by a microscope in order to reveal the adequate position and direction of the sample for measurements of texture. From the microphotograph of frozen unfixed fresh Shiitake mushrooms stained with periodic acid Schiff, differences were found in the density of the hyphae. The hyphae showed a high density of 1-2 mm in width at the base of the gills in the pilleus, but in the interior of the pilleus, they showed a low density. This result showed that the central parts of the pilleus which were used in previously reported examples were not suitable for measuring the firmness of Shiitake mushrooms. Consequently, we must shape the Shiitake mushroom to include the base of gills in the pilleus, and the plunger must touch them in parallel with the stem.
Shiitake mushrooms were placed on a doughnut-type platform so as to meet these conditions, and the penetrating tests were carried out with a 1.5-mmφ cylindrical plunger. As a result, we could determine the rheological properties of Shiitake mushrooms and moreover, the parameters of the breaking properties, which represent the index of firmness, especially the breaking strain, were in good agreement with the firmness determined by sensory evaluation. This result shows that the position and direction of the Shiitake mushroom used in our experiments is appropriate.

抄録全体を表示

We investigated the relationship between the frothing and foam stability of beer and the surface properties of various kinds of drinking vessel (glass mugs and 6 kinds of ceramic mugs), whose size and shape were almost the same. Although the initial bubbles produced when pouring beer into a mug have been thought to depend on the gas created by the mechanical stirring and on the air adsorbed to the surface of the beer mug, we considered that the frothing and foam stability of beer in the mug might also be related to the shape and size of scratches and on the wettability of the surface of the beer mug. The mechanism for continuous bubbling was investigated by a theoretical equation which showed that the size of a bubble produced on the surface of the beer mug was significantly correlated with the wettability and shape of scratches on the surface, and that the place where a bubble was continuously produced was where air remained to form the nucleus of the next bubble after the previous bubble had been released.

抄録全体を表示

The effect of sucrose on the physical properties of low-moisture dough and its baked products was investigated. The dynamic viscoelastic properties during baking and DSC values for each dough sample, and the solubility of gluten in wheat flour were measured.Microscopic observations were made, and the change in visual shape and rupture properties of the baked products were also measured.
During the initial stage of preparation, sucrose dissolved in water enacted on the wheat flour components as a sucrose solution, resulting in an inhibiting action on the gelatinization of starch. It simultaneously inhibited the formation of gluten, making the dough tender. This resulted in increased brittleness of the baked products containing sucrose which became much harder in texture. This suggests that sucrose partly remained in the crystal form during the dough preparation procedure and formed a glass-like structure during heating.
The fluidity of the dough containing sucrose during heating was increased, resulting in greater spread of the dough. The action of reducing the viscosity of the dough lasted for a much longer period of heating with increasing amount of sucrose added.

抄録全体を表示

The taste property of cooked rice was studied by both chemical analysis and a sensory test of extracts of the cooked rice. Three kinds of aqueous solution containing 30%,50% and 80% ethanol were used for extraction. The amount of total sugars contained in the extracts prepared from the cooked rice (Nipponbare) was drastically decreased with increasing concentration of ethanol. The amounts of such components as reducing sugars contained in the 80% extract were significantly less than those extracted with 30% and 50% ethanol. The taste of the aqueous solution of the 50% ethanol extract of the cooked rice was most similar to that of the cooked rice in the sensory test. All of the extracts tasted umami, bitterness, acridity and astringency as well as sweetness. The 50% ethanol extract showed these taste characteristics more strongly than the other extracts, and this feature of the 50% ethanol extract of cooked rice was confirmed to be common to other cultivars of rice such as‘koshihikari’and‘Mutsuhomare’. Gel-permeation chromatography of the 50% ethanol extract of cooked rice (Nipponbare) indicated that the relatively low molecular weight fraction had a complex taste character.

抄録全体を表示

The vitamin C content of 12 species of fresh herbs was 45∼170 mg/100g fr. wt., this being 2∼6 times higher than that of spinach.22 species of fresh herbs, especially those of the Labiatae, contained very high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and polyphenol content. The highest values for the radical-scavenging activity and polyphenol content of fresh herbs were respectively 76 and 44 times higher than those of spinach. The radical-scavenging activity of fresh herbs was positively correlated with the polyphenol content (R²=0.958, n=27), but not with the vitamin C content (R²=0.031, n=16). Both the radical-scavenging activity and polyphenol content of fresh herbs were increased by boiling in a 2% sodium chloride solution. The polyphenol content of fresh herbs would account for their radical-scavenging activity.

抄録全体を表示

We examined the effect of sauteing method on the quality of sauted bean sprouts.
The quantity of water which separated from the sauted bean sprouts was more in an iron pan than in a teflon pan, and decreased significantly with increasing sauteing time.
The quantity of oil which separated from the sauted bean sprouts was amounted to 50% of the quantity of sauteing oil with a 30-second saute heatment.
While the influence of sauteing time on the POV and TBA values was small, there was an effect from the kind of pan material, particularly when an iron pan used.
Sauted bean sprouts had a higher rupture stress and smaller rupture strain than raw bean sprouts.
The final temperature of sauted bean sprouts was higher when sauted after boiling the bean sprouts for 30 seconds than without boiling.
The sensory evaluation showed no difference in the taste of bean sprouts sauted in iron and teflon pans, although there was a significant difference in the sauteing time. There was a preference for bean sprouts sauted for 30 sec after boiling than those sauted for 30 sec without boiling.

抄録全体を表示

Rice grains cooked in hot water (100°C) for selected periods of time were quenched and dissected into thin slices (40μm). The birefringence images of these slice showed the gelatinized region to be clearly separated from the ungelatinized region, enabling the progress of gelatinization to be visualized in the grain during cooking. It was observed that the gelatnization was initiated from the outer surface as well as from cracks which formed when the grains were immersed in water. These cracks facilitated the progress of starch gelatinization in the grain, resulting in the formation of two or three spherical ungelatinized regions in the grain in the late period of cooking.

抄録全体を表示

The radical-scavenging activity of commercial alcoholic drinks (130 samples of wine, fruit wine, medicinal liqueur, beer, liqueur, whiskey, sake, shochu, etc. ) was evaluated by monitoring the 1,1dipheny1-2-picrylhydrazyl (DPPH) radical. The contribution of ascorbic acid and polyphenol to this activity was also determined.
Many of the commercial alcoholic drinks had DPPH radical-scavenging activity. Wines had high radical-scavenging activity, those containing the highest levels of polyphenols having the highest activity. The radical-scavenging activity of fruit wine and liqueur depended on the fruit used, and the darkness of beer contributed to the activity. The DPPH radical-scavenging activity of medicinal liqueur was low, and whiskey, sake, and shochu showed practically no activity. The DPPH radicalscavenging activity and polyphenol content of commercial alcoholic drinks were found to be highly correlated.

抄録全体を表示