Texture is an important evaluation item for foods. Food, being heterogeneous, changes texture dynamically during oral processing. The physical properties of foods are perceived as textures owing to the various receptors in the oral cavity. Therefore, methods to evaluate the stress distribution in solid foods during compression / biting and the flow characteristics of liquid foods using sheet sensors with many pressure-sensing points were designed. Artificial tongues were introduced to evaluate soft foods that were easily broken between the tongue and hard palate, such as commercially-available nursing foods and soft hydrocolloid-gels as models of care foods. Compression tests were conducted using a soft machine with an artificial tongue. As the artificial tongue deformed and surrounded the food materials, foods with high fracture deformation ratios during the conventional test using a hard machine were evaluated without being subjected to fracture by the soft machine. These results suggest that the fracture deformation of foods is an important factor in food destruction during compression between the tongue and hard palate. The presented methods are suitable for a variety of application such as the texture evaluation of heterogeneous foods, development of processed foods composed of various ingredients, and universal design of food utensils.

For the realization of a sustainable society, utilization of underutilized/low-utilized food resources is essential. This paper describes various methods for effective utilization of these resources. The authors have developed a process for the esterification of sterol/triterpene alcohols and separation process of conjugated linoleic acid isomers by lipase-catalyzed reaction. Subcritical water treatment of defatted rice bran and krill is also described, and it was found that the extracts contained antioxidants. Furthermore, mechanism of the reaction, such as degradation of dipeptides, occurring during subcritical water treatment was clarified. Isomerization behavior of sugars during their subcritical water treatment was also analyzed to provide a means of producing rare sugars. In addition, we proposed a method for producing soybean-based meat analogue through gelation of alginate and formation of tissue-like structures by slow freezing. Furthermore, edible thermal storage microcapsules were prepared by encapsulating coconut oil by complex coacervation, and their performance to suppress temperature change was clarified.

The waste rate of watermelon juice by using the white part of the rind was in the range of 20 to 30% at all days after pollination (DAP), which was lower than the 40% listed in the Standard tables of food composition in Japan. The color of the juice fluctuated with a peak at 40 DAP, based on L^＊ and a^＊ values. The brix of the juice stabilized after 40 DAP, when the fruit was fully ripe, and was maintained at about 10 °Bx, suggesting that the juice could be used. Each 100 g of the juice contained 164.7 mg of citrulline (40 DAP), 41.9 mg of arginine (50 DAP), 16.5 mg of γ-aminobutyric acid (50 DAP), 3.34 mg of lycopene (40 DAP), and the singlet oxygen absorption capacity value was 8.62 μmol α- tocopherol equivalent/mL (40 DAP). The correlation between singlet oxygen absorption capacity values (y) and a^＊/b^＊ values (x) was strong (correlation coefficient = 0.915), and a regression equation (y = 5.824 x − 4.448) was obtained, suggesting the possibility that the a^＊/b^＊ values can predict singlet oxygen absorption capacity values.

Measuring protein concentration C_P is important for many unit operations at food or bio-industry such as bioreactors, adsorptions, chromatography separations, and concentration operation by ultrafiltration. Although various methods are available, most of them are not suited for measuring high C_P. In this paper we have developed a method for continuous monitoring of very high C_P by optical rotation (OR). A flow-cell was built based on the standard cell. Linear correlations were confirmed between OR and C_P in the range C_P = 0 to 20 g/L, the slope of which was similar to that obtained for the batch measurement. As the flow-cell volume is large, the effect of the input signal shape on the output signal was analyzed based on the mechanistic model considering the continuous stirred tank reactor and the plug flow reactor. This method was applied to the continuous monitoring of C_P during concentration by ultrafiltration. The measured C_P values (C_P = 12 to 68 g/L) were in good agreement with the off-line measured values by the absorbance at 280 nm after dilution.

Dried foods are often cooked in boiling water prior to their consumption. Dried spaghetti is one such food. The normal cooking method for dried spaghetti is to rehydrate it in boiling water, which consumes energy during heating. Here, we sought to find ways to minimize this energy use. Changes in moisture content and force-deformation curve over time were measured when spaghetti was placed in water at room temperature and heated at various power levels using an induction heater. These changes were also measured during the normal cooking method. The energy consumed by different power levels was compared when spaghetti with an initial diameter of 1.6 mm was cooked to 1.6 g-H₂O/g-d.m. The lower the power level of the induction heater, the less energy was consumed and the lower the force at breaking deformation. When cooked non-isothermally at 935 W, the highest power level of the induction heater used, the force at breaking deformation was almost the same as that of spaghetti when cooked normally in boiling water. However, the energy consumption was greatly reduced, by about 60%, during the non-isothermal cooking. This suggests that energy consumption could be reduced when cooking spaghetti by placing it into water at room temperature and rapidly heating the water rather than cooking the spaghetti in boiling water.