本研究藉添加澱粉液化酵素(α-amylase)探討對麵糰及土司物化性質之影響。實驗結果顯示，未添加α-amylase之麵糰，發酵速率最慢，發酵速率最快者爲添加50 ppm α-amylase之麵糰。土司於貯存過程中，硬度值增加爲土司老化程度重要指標之一，由實驗中可看出，未添加α-amylase之土司，硬度值最高，添加α-amylase 後可使土司麵包變的更柔軟。貯存4天後，未添加α-amylase 者，其土司硬度值增加至115.1g，添加10 ppm α-amylase 者，土司硬度值爲106.1 g，硬度最低者爲添加50 ppm α-amylase 之土司，其硬度值爲86.5g。以掃描式電子顯微鏡觀察未添加α-amylase 之麵糰，發現小澱粉顆粒呈環狀分布於gluten matrix上，且gluten matrix 表面平整，但添加α-amylase之麵糰，可看出小澱粉顆粒較少，且gluten matrix 表面較不平整，出現許多澱粉小突出物。進一步觀察土司內部組織，可明顯看出添加20 ppm 及50 ppm α-amylase之土司組織較爲細緻，孔洞壁膜較薄，說明了添加α-amylase可使土司組織更加細緻。 This study evaluated the effects of α-amylase addition on the dough mixing characteristics and the quality of toast. Dough with α-amylase addition had a faster dough fermentation rate than that of the control. The dough with 50 ppm α-amylase addition had a fastest fermentation rate. During storage, the increase of hardness is often used as an index of staling in bread. The hardness of control bread increased from 68.2 g to 115.1 g after 4 days storage. However, with the addition of 50 ppm α-amylase, the hardness of toast increased from 51.1 g to 86.5 g after 4 days storage. According to the scanning electron micrograph of control dough, numerous small starch granules were visible on the outer surface of gluten matrix. The doughs with α-amylase addition also showing numerous starch granules were coated with an amorphous protein matrix, but some protruding substances were present on the surface. The interior structures of toast were further examined. Toasts with 20 ppm and 50 ppm α-amylase addition have thinner walls and finer crumb grain structure than the toast without α-amylase addition. Scanning electron micrographs showed that toast with the addition of α-amylase exhibited more delicate crumb microstructures.