This paper presents the results of a study on meat quality and protein alterations of fast glycolyzing (FG) and normal glycolyzing (NG) turkey breast muscles. In a commercial processing plant, 34 breast muscles were sampled at 20 min postmortem from a large flock: 17 samples showing the lowest pH(20min) (6.04 +/- 0.09; FG) and 17 showing average pH(20min) (6.47 +/- 0.01; NG). Over a 9-d storage period at 4 degrees C, L* values did not differ between the 2 groups. The FG group showed higher drip, thawing, and cook loss values, and lower processing yield than the NG group. Warner-Bratzler shear force values of cooked meat were higher in the FG group than in the NG group. The FG meat presented a lower protein extractability with low ionic strength buffer than the NG meat. No differences in SDS-PAGE banding patterns were detectable for the different protein extracts between the 2 groups. On the contrary, when SDS-PAGE gels were performed on basic proteins, they showed differences in banding intensity for 2 proteins: glyceraldehyde-3-phosphate dehydrogenase and aldolase A.