@article{oai:repository.naro.go.jp:00001388,
 author = {伊藤, 美環子 and ITO, Miwako},
 journal = {北海道農業研究センター研究報告, Research BUlletin of the NARO Hokkaido Agricultural Research Center},
 month = {Mar},
 note = {Breads and yellow alkaline noodles (YAN) account for almost 50% of all wheat products consumed in Japan, but a large proportion of the hard wheat used for breads and YAN is imported. To deal with such a situation, many domestic varieties of hard wheat have been developed in recent years. In the present study, we examined the processing abilities for breads and YAN of these new varieties, and we tried to develop a selection method for an improved flour quality for YAN color. 1. Relationship between bread-making quality (texture and staling of breads) and flour quality The texture and staling of breads made from four flours, two new Japanese bread wheats, Haruyokoi and Kitanokaori, and two representative bread wheats, 1CW (No.1 Canada Western Red Spring) and HRW (Hard Red Winter) , were evaluated. Breads, flour gels and starch gels made from the two Japanese flours were very soft just after baking and had higher levels of cohesiveness than those of 1CW and HRW. The two new breads in the early stage of storage had lower hardness and higher cohesiveness values than those of the others. From analysis of bread staling and retrogradation of starch in bread, it was proven that starch retrogradation of the new breads in the early stage was slower than that of the others. These results showed that slow staling, especially staling in early stage, and extreme softness just after baking of the two new breads were attributed to the soft texture and low retrogradation of starch gel in the breads, which was related to lower amylose content of these new flours. 2. Relationship between YAN quality （texture and color） and flour quality We examined the relationship between the flour or starch properties and the YAN color or physical properties of Kitanokaori, Haruyokoi and three other samples. A time-course experiment showed that a raw noodle sheet made from Kitanokaori had less reduction in color brightness than sheets made from other flour samples, which had high PPO activity. This finding, therefore, suggests that the brightness stability of the Kitanokaori noodle is caused by its low PPO activity. Regarding physical properties and texture, Kitanokaori and Haruyokoi had high elastic indices of starch gel and YAN as a result of low amylose content. The results of the comparison demonstrated that the superior qualities of YAN made from Kitanokaori can be attributed to the low PPO activity and low amylose content of the flour. 3. Development a method for improved YAN quality (YAN color) We examined a method for improved flour color and stability of YAN color. We tried to develop a method for evaluating flour color by determining the color of the cross-section of wheat endosperm unaffected by mixed bran. Samples were prepared as follows. The grains were cut crosswise into 2mm-thick slices, and then the seed coat was removed and the grains were soaked in distilled water for 4 hours. The color values (L^*a^*b^*) of the cross-sections of the samples were determined using a microspectrocolorimeter. The three color values for the cross-section were highly correlated with those of the pure endosperm powder devoid of mixed bran. Therefore, we concluded that the color of the cross-section of wheat endosperm evaluated by this method can be applied for selecting lines that have superior color of the endosperm. The bright and yellow color of YAN is a desirable end-use quality. It was possible to estimate the grain PPO activity by the 3,4-dyhydroxy-L-phenylalanine （L-DOPA） method, which is a simple method for evaluating wheat grain PPO activity, using grains of hard wheat varieties from the Hokkaido region of Japan. However, the correlation of grain PPO activity with YAN discoloration was lower than that of flour PPO activity. Therefore, a simple method for evaluating PPO activity using wheat flour was developed to achieve more efficient selection for the breeding program. In this method, a glass test tube with a flat bottom containing 0.2g of wheat flour and 4 ml of a 10 mM L-DOPA solution was shaken for 1 hour and left for 18hours at room temperature ; the L^*, a^*, and b^* values of the suspension were then measured. There was a high negative correlation between the L^* value measured by the present simple method and the PPO activity in wheat flour measured by the conventional method (oxygen-electrode method). Therefore, we concluded that the L^* value measured by the simplified L-DOPA method can be applied for selecting lines that have lower PPO activity and consequently less YAN discoloration.},
 pages = {1--92},
 title = {硬質コムギの二次加工適性の評価及び品質改善のための選抜法に関する研究},
 volume = {191},
 year = {2009},
 yomi = {イトウ, ミワコ}
}