White people were apprehensive about the African-American soldiers. They didn't think that the soldiers were that good as soldiers since they didn't serve in a military and were new to all of the things in war. They also didn't consider themselves to be equal to them since they were white and the people in question were still African-American.
Some attitudes changed and some didn't. Although most of them still remained racists according to our contemporary understanding of the world, they did appreciate the african-american effort in the war since the african-americans worked hard and fought for the union and helped them win the war.