Microencapsulation of liquid lipid with a wall material can suppress its oxidation. Integrated investigation on the mechanism for the suppression revealed that interaction of the lipid with the wall material played an important role. Fatty acids were condensed with hydrophilic food components using immobilized lipase in a water-miscible organic solvent to produce a variety of emulsifiers. It was found that an interaction between water and hydrophilic substrate or between fatty acid and the solvent greatly affected the apparent reaction equilibrium constant. Continuous or semi-continuous reactor systems were also constructed for the production of the emulsifiers on a large scale. The solubility of fatty acids in subcritical water was measured. The measurement brought about a proposal of a novel method for preparing an oil-in-water nano-emulsion.
This study is the manufacturing methods of solid foods (a seasoning of fish sausage, tuna and jam) on good color and flavor with high temperature and short time sterilization by microwave heating. We investigated the cause of the inner temperature difference inside model solutions instead of solid foods. A heating test conducted on the model solutions revealed that the major cause of the inner temperature difference was NaCI. So, it is necessary to heat the inside of food with uniform heating for the sterilization of solid foods. We obtained an effective method of reducing the temperature difference within. It was possible to reduce the edge effect on solid foods by dipping in distilled water. The reason is distilled water behaved edge of solid foods. For half depth of microwave was enough distance in distilled water, it did not make the heating efficiency of foods decrease remarkably. In future, we want to proceed with further research on the sterilization technology of solid food with model examination by continuous heating, and reducing the edge effect on the temperature change of solid foods.
Hot-Compressed-Water (HCW) treatment of chinquapin, a hardwood, was performed using a percolation reactor. In this study, production behavior of xylose and xyloologosaccharides derived from hemicellulose in the chinquapin was investigated from the view point of pressure (5-20 MPa) and temperature (160-260°C) condition. The reaction temperature showed remarkable effect on the yields of xylose, xylobiose and xylotriose, while pressure had no effect on them. The yields of these three saccharides increased as the temperature became higher and peaked at 220°C. However at the temperature condition of 240°C, the yields of these three saccharides decreased, while glucose and cellobiose were obtained by hydrolysis of cellulose. By the IR analysis of Water solubles, it was confirmed that a part of lignin was solubilized together with hemicellulose in these experimental conditions.
Among the various drying methods, vacuum freeze drying offers the advantages of a minimum level of quality deterioration and a very high degree of rehydration. However, vacuum freeze drying is rarely used industrially on thick and bulky sea foods such as the scallop, because dehydration by ice sublimation is very energy-inefficient and it takes long time to dehydrate foods. Solar drying and hot air drying bring about significant differences in food color and texture. Thus the present study aimed to develop a drying method that is capable of preserving a food's original properties as much as possible. This report discusses our investigation of a novel method of vacuum drying using FIR. Using this method, food preprocessed by boiling or other processes is not frozen, but is immediately transferred to a drying stage, and food is dehydrated under conditions which do not freeze the product until it is completely processed. The samples used in the present study were the adductor muscles of scallop, which is too thick and bulky for vacuum freeze drying. The quality of the product obtained by FIR vacuum drying was almost the same as that obtained by vacuum freeze drying with respect to color, shrinkage, hardness, rehydration efficiency, and sensory tests.
Monodispersed water-in-oil emulsions were prepared successfully using polymer microchannel (PMC) with hydrophobic property, low cost and high anti-alkalinity fabricated by molding injection method. In order to enhance the efficiency of PMC emulsification, it is important to know the critical flow velocity of the dispersed phase, and the critical pressure at which the dispersed phase outflow occurs. In this study, we investigated the effect of the continuous phase flow velocity on the average droplet diameter, coefficient of variation, and the critical pressure during the PMC emulsification process. Furthermore, aiming the optimization of PMC pattern for efficient production of emulsion, various PMC plates with different structures were fabricated, and were used for emulsification. The effects of various parameters on droplet formation characteristics were investigated. The results showed that the continuous phase flow velocity did not affect the average droplet diameter and coefficient of variation, but affected the critical pressure. The critical flow velocity increased slightly, when PMC plates with different structures were used. In particular, the average droplet diameter range became wider, coefficient of variation decreased, and the critical flow velocity increased significantly with the increase of PMC length, which showed higher productivity of the emulsion.
The effect of sugar solutions (sucrose and trehalose) pre-treatments on the rehydration properties and changes of micro structural properties of carrot and potato slices has been investigated, and compared with no-treated and steam blanched samples. Samples (sliced potato and carrot) were dried in an constant air-temperature box at 323 K, and subsequently, they were rehydrated in water at 298 K and 373 K. Results showed that rehydration properties of dried samples treated with sugar solutions were improved compared with blanched and no-treated samples. According to microscopic measurements and observations pre-treatment of trehalose solution improved the reconstitutional properties of both carrot and potato samples.