Found this on a website and appears to be from regulations:

Table 1 -- DAILY UNION ARMY RATION

3 August 1861 –20 June 1864

CAMP AND GARRISON RATION:

Meat: 12 ounces of pork or bacon, or
1 pound and 4 ounces of salt or fresh beef

Bread: 1 pound and 6 ounces of soft bread or flour, or
1 pound of hard bread [hardtack] or
1 pound and 4 ounces of corn meal

To every 100 rations:
15 pounds of beans or peas, and
10 pounds of rice or hominy
10 pounds of green coffee, or
8 pounds of roasted (Or roasted and ground) coffee, o
1 pound and 8 ounces of tea
15 pounds of sugar
4 quarts of vinegar
1 pound and 4 ounces of adamantine, or star candles
4 pounds of soap
3 pounds and 12 ounces of salt
4 ounces of pepper
30 pounds of potatoes. when practicable. and
1 quart of molasses

Paragraph 1191: "Desiccated [dehydrated] compressed potatoes, or desiccated compressed mixed vegetables, at the rate of 1 ounce and ½ of the former, and I ounce of the latter. to the ration, may be substituted for beans, peas, rice, hominy, or fresh potatoes.

MARCHING RATION;

Meat and Bread; same as above
Coffee, Sugar, and Salt; same as above

This info and more at: http://www.qmfound.com/feeding_billy_yank.htm