The function of mulberry leaves and the quality of muffins including mulberry leaves were examined. The electron donating ability of both a water and ethanol extract was 40% for both at 100 ppm, 62 and 72% at 500 ppm, and 77 and 83% at 1,000 ppm respectively. These experiments showed good oxidized substance activity. The SOD-like ability of the water and ethanol extracts at 1,000, 500, and 300 ppm was 49% and 55%, 33% and 39%, and 28% and 33% respectively. These results show that the ethanol extract had higher SOD-like ability than that of the water extract. The nitrite scavenging abilities of 1,000 ppm of the mulberry leaf water extract and ethanol extract at pHs of 1.2 and 3.0 were 40.5 and 47%, and 20 and 22% respectively. The Hunter lightness value tended to be lower as the amount of added mulberry leaves increased compared to the contrast set, so the lightness level with a 7% addition was the lowest. The contrast set was the highest for redness and added mulberry leaves tended to decrease redness at 3% but tended to increase it again with additions >3%. The b-value (yellowness) showed a similar tendency as redness. Adding Mulberry leaves tended to decrease the contrast set to the lowest level, then values increased slowly to a peak at 5% added mulberry leaf and then decreased thereafter. Strength and hardness were less after increasing added mulberry leaf. Cohesiveness, springiness, gumminess and brittleness, decreased at up to 5% added mulberry leaves but the 7% addition showed the same level as the contrast set. The mulberry leaves muffins were less preferred to the contrast set in appearance and color. However, the mulberry leaf muffins were preferred to the contrast set in taste and flavor but the result was not significant. Overall the quality of the muffins with 3% added mulberry leaves was preferred over the 1% added mulberry leaf muffins.