The diffusion coefficient and change in NaCl concentration of root vegetables during cooking were studied. Japanese radish, carrot and potato cut in 2-cm cubes were soaked in a 0.2 M brine solution at 20, 50 and 70°C for 16, 8 and 6 hrs, respectively, for measuring the NaCl diffusion coefficient. The value for the diffusion coefficient of NaCl was in the order of Japanese radish, carrot and potato, suggesting that vegetables obtaining more water had higher diffusion coefficient. The diffusion coefficient of a 2-cm cube of radish soaked in 0.2-0.8 M brine solutions showed little dependence on the concentration of brine solution. The predicted and experimental values for the average NaCl concentration of each volume element agreed with each other when using the obtained diffusion coefficient under different temperature, brine concentration and time conditions. It was possible to predict the average or distribution in concentration of NaCl of a sample treated as a set of 1 mm3 of volume element by using the finite difference equation.
The effects of the properties of oil and fats on the ease of swallowing mashed potato were examined to compare samples with added oil or fat with those with water (control) added in the same proportions. The comparison was made by measuring the physical properties and conducting a sensory evaluation. The samples of the mashed potato were prepared by adding water as the control, and liquid oil O, solid fat F (fat-like gel) and solid fat S (shortening) to give three different physical properties of fats and oil. The hardness and yield stress of the mashed potato were greatly influenced by the physical properties of the solid fats. The average resistance force obtained by measuring the resistance in the horizontal direction gave an indication of the ease of sliding and smoothness of the sample to show the validity of this method. Microscopic observation of the mashed potato showed that the dispersion was different among water, oil and fats, and influenced the physical properties. A sensory evaluation showed the sample with added water to be significantly harder than the samples with added oil and fats, and tended to be less smooth. The samples with added water and oil were evaluated to be significantly lower in their thickness and sense of remaining in the mouth, and higher in their ease of swallowing than the samples with added solid fat F.
We investigated the physical properties, sensory characteristics, and electromyography (EMG) of minced daikon-sol mixed samples to identify how the difference in daikon hardness affected the ease of eating. Minced daikon-sol mixed samples were prepared by adding a thickening liquid to minced daikon. The minced daikon was prepared to three different levels of hardness: by heating under pressure (MP), by steaming (MS) and by leaving uncooked (MR). A sample of steamed daikon alone (daikon S) was prepared as the control. The overall results from the subjects eating the samples indicated the hardness of the prepared daikon to be more crucial than the overall hardness of the sample. Daikon S was eaten with the lowest muscle activity, and was evaluated to be easier to swallow than MR. These findings suggest that, improving the ease of eating minced food can be better achieved by softening the solid component than by mixing the minced food in to a sol.
Changes in the internal temperature, hardness and NaCl concentration of a sample were simulated by computer program using measured changes for 1-4 kg of water for cooking root vegetables by boiling for a given time and using residual heat. The seasoning time for the whole sample to obtain the optimum average NaCl concentration, and the softening time for the center of the sample to reach the optimum hardness were calculated. Samples of 1-3 cm cube of Japanese radish, carrot and potato were used. The calculated seasoning time was in the order of potato>carrot>Japanese radish, and softening time was in the order of Japanese radish>carrot>potato, the larger the surface area with the same volume, the shorter the time for both. The , seasoning time was longer than the softening time without residual heat, except for the 1-cm cube of Japanese radish. With residual heat, the softening time was longer than the seasoning time with a large quantity of water in the case of a 2- and 3-cm cube, and for any quantity of water in the case of a 1-cm cube.
The effect of water hardness on the scum formed during soup stock preparation was examined. Three kinds of mineral water were used for preparing the soup stock, in addition to artificial mineral water with various levels of hardness that was prepared by adding calcium sulfate or/and magnesium sulfate. The weight of scum formed with the three kinds of mineral water was statistically heavier than that formed with distilled water, although the weight of scum was not proportional to the water hardness. All samples of artificial mineral water prepared with only calcium sulfate or magnesium sulfate formed statistically heavier scum than distilled water, the weight of the scum formed being proportional to the hardness. However, calcium sulfate caused more scum formation than magnesium sulfate. In the cases of artificial mineral water prepared with mixed calcium and magnesium, the scum formation was suppressed more than in artificial mineral water containing only calcium sulfate. The calcium content in the scum was increased in accordance with that in the mineral water samples used for preparing the soup stock, although there was no substantial difference in the contents of protein and the other minerals. It was concluded that scum formation was affected by the calcium content of the water, rather than by the water hardness up to about 1,000 hardness, and that an increase in the ratio of the magnesium content suppressed scum formation.
We evaluated the superoxide radical scavenging ability of green tea by the ESR spin trapping method. This method generated very pure superoxide by visible ray illuminating a phosphate buffer solution containing riboflavin. The ESR adduct signal was sensitive and very stable. We conclude that the ESR spin trapping method is suitable for evaluating the superoxide radical scavenging ability of green tea.
“Aobanokoi” wheat was grown with a higher-than-normal application of fertilizer. The grains were then harvested, milled, and used to produce Shiroishi dry noodles. The breaking strength of the boiled noodles increased when the protein content of the fruiting body increased from 8% to 12%, but tended to decrease when the protein content exceeded 13%. An increasing protein content also tended to increase the percentage of the gliadin fraction, the ratio of the gliadin fraction/glutenin fraction increasing more than twice when the protein content exceeded 13%. It is thought that the formation of gluten became harder with a high gliadin/glutenin ratio. This finding can be applied to manufacture firm dried noodles.