We investigated the rheological properties of the Japanese wheat product tenobe somen noodles manufactured using a unique traditional process-"Te-nobe (hand-stretched)." In an extension test, the maximum resistance to extension (R(max)) and extensibility until rupture (Erup) of boiled somen noodles were measured on a Texture Analyzer in the tension test mode and compared with those of machine-made somen noodles. The R(max) and Erup values per unit cross-sectional area were significantly higher for boiled tenobe somen noodles than for machine-made somen noodles, clearly indicating the higher resistance to extension and extensibility of the former. A compression test performed using the Texture Analyzer in the biting-test mode revealed that although the maximum force of compression (F(max)) was lower for boiled tenobe somen noodles than for machine-made somen noodles, the former had more characteristic texture than the latter, which was shown by comparing the force-deformation curve of each somen noodle. Scanning electron microscopy revealed differences between dried tenobe and machine-made somen noodles, which may reflect their rheological differences. Lateral and sectional micrographs of tenobe somen noodles showed regular arrays of starch granules and gluten networks, and some air spaces. Tenobe somen noodles exhibited significantly higher dityrosine content than the flour used for their manufacture, indicating that tyrosine residues in gluten proteins cross-link during the manufacturing process; however, the dityrosine content in tenobe somen noodles were not higher than that in machine-made somen noodles.

Changes in expression and accumulation of gluten proteins were investigated in developing kernels of 2 wheat cultivars, Norin 61 and Fukusayaka. Expression of 7 gluten subunit genes was detectable 7 days after anthesis (DAA) in both cultivars, while changes in expression patterns of these subunits over time were found to be specific to each cultivar. The accumulation of total proteins and ethanol-soluble proteins was analysed by SDS-PAGE and acidic-PAGE, respectively. The band patterns of total proteins in both cultivars changed markedly between 14 and 21 DAA. Ethanol-soluble proteins, which are mainly gliadin proteins, were detected at 21 DAA in Norin 61 and at 14 DAA in Fukusayaka. We investigated the textural properties of dough prepared from the flour of mature and immature Norin 61. The tension test revealed that dough prepared from immature wheat had higher tensile strength and lower extensibility than that prepared from mature wheat.

Tenobe somen (TS) noodles are traditional Japanese wheat-based noodles that are produced manually using a sophisticated method called tenobe (literally, "hand stretched"). In the tension test, both the tensile strength and extensibility of TS noodles were greater than those of machine-made (MS) noodles. In the biting test, the chewy texture of TS noodles was realized in the analysis of the force-deformation curves of each type of somen noodles. The creep test indicated a clear difference between the external and internal elasticity of TS noodles. The texture of TS noodles appeared to change dramatically during storage in the rainy season. In addition, firm and chewy textures of TS noodles stored for 20 mo were observed. Similar to the results from our previous study, TS noodles exhibited significantly higher dityrosine content than the flour used for their manufacture. However, the increase in the dityrosine content during the manufacturing process was not observed in the case of MS noodles. Although clear textural differences were observed between TS noodles stored for 0 and 20 mo, the dityrosine contents of TS noodles at each stage were not largely different.

In this study, effects of constant-temperature preheating (40, 50, 60, 70, 80℃) on physical properties of Japanese apricot (Prunus mume) jam were investigated. Breaking stress of jam was temperature-dependently increased by preheating, and this value reached maximum with preheating at 60℃ for 30 min. Shape retention of jam in a 200℃ oven was strongly correlated with breaking stress; that is, the jam prepared from fruit treated at 60℃ for 30 min was the most stable against heating (200℃, 10 min). During constant-temperature preheating, soluble pectin in fruit was temperature-dependently increased by heating, whereas the molecular size of soluble pectin was gradually decreased. Pectin solubilized by preheating at 60℃ for 30 min would be the most favorable for gelation, as the definite quantity of solubilized pectin was above the specified molecular size. Acid hydrolysis during preheating is suggested to play a role in solubilization of pectin. Constant-temperature preheating is expected to be a new technique for controlling and utilizing internal constituents in food materials.