Preheat oven to 325°F. Beat butter, granulated sugar and sour cream in large bowl with electric mixer on medium speed until light and fluffy. Add eggs, 1 at a time, beating well after each addition. Gradually beat in flour and baking soda on low speed until just blended.
Remove 1 cup of the batter to small bowl. Stir in raspberry flavor and red food color. Stir lemon extract into remaining batter. Pour 1/2 of the lemon batter into greased and floured 9x5-inch loaf pan. Top with 1/2 of the raspberry batter. Repeat layers. Run a knife through batter to swirl raspberry batter into lemon batter.
Bake 1 hour or until toothpick inserted in center comes out clean. Cool in pan 10 minutes. Remove from pan; cool completely on wire rack.