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The e#ect of microwave heating on breaking properties of confectionery was studied by using two methods. One method (I) used the baked products as cookies of which material contained wheat-flour, butter and low content of water. The other (II) used commercial confectionery heated by microwave after moisture absorption. (+) The breaking energy of the microwave heating products was triple higher compared with the conductive, and was approximated to the value of the conductive products of which material contained higher water about +*῏,*ῌ. In the sensory evaluation, the texture characteristic of microwave was estimated to be hard, not short, di$cult crunch and chewy. (,) A high, positive correlation was obtained between the breaking properties and the starch gelatinization values, and then a paste material was suggested to be an important factor for hardening. (-) A moisture absorption sample contained about +/ῌ water, in the microwave heating, began increasing starch gelatinization and breaking properties. It is assumed that the temperature raising behavior in low moisture might accelerate the physical properties changing.

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The e#ects of moisture and temperature on the textural properties of a commercially produced cookie and senbei were examined by measuring breaking properties under storage conditions of relative humidity (RH) 1.0ῌ31῍ at four temperatures, /, ,*, .* and 0*. A cookie with low gelatinization characteristics was softened with small amounts of moisture. Although the degree of softening was small at /, it increased significantly with an increase in temperature. The cookie had a low moisture content and was softened with ductile fraction at 0*. The senbei, with high gelatinization characteristics, became hard, containing ++ῌ+2 g moisture/+** g dry matter. The maximum hardening value of senbei was reached at less than ++ g moisture/+** g dry matter at .*. This was thought to be due to the fact that the glutinous strength of gelatinized starch has a maximum value at around .*. The amount of moisture sorption per +** g dry matter of the cookie required to maintain hardness was approximately 2 g at /, 0 g at ,*,. g at .* and g at 0*. The amount of moisture sorption per +** g dry matter of the senbei required to keep hardness was approximately ,* g at / and ,*, and +0ῌ+1 g at .* and 0*. The maximum amount of moisture sorption required for senbei to soften was large compared to that of the cookie. Based on textural evaluations, brittleness was lost and crunchiness maintained in cookies kept under RH /0῍ (1 g moisture/+** g dry matter). While the senbei under RH 02῍ (+-g moisture /+** g dry matter) was perceived to be moist and sticky, it was not easy to bite o#.

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