Combine first 7 ingredients in a large bowl; make a well in center of mixture.
Stir together egg, orange juice, and butter; add to dry ingredients, stirring just until moistened. Fold in carrot and zucchini. Spoon into greased muffin pans, filling two-thirds full.
Bake at 400º for 20 minutes. Remove from pans immediately, and cool on wire racks.
NOTE: Freeze in an airtight container up to 3 months. To reheat wrap each muffin in a damp paper towel; microwave on HIGH 40 seconds or until warm.