Wheat flour and other ingredients, such as water, milk, salt, eggs, sugar, and fat, are used to prepare cakes. Different interactions occur among these constituents, changing the nutritional and technological characteristics of the final product. Replacing white flour with whole flour and water with milk will increase the final product’s protein content. In this study, the effect of replacing white flour with whole flour and water by milk on the contents of total, soluble and insoluble proteins in cakes, prepared with domestic procedures, was evaluated to infer protein availability in the end product. Ingredients were purchased in retail. The cakes were prepared according to AACC recommendations under different formulations: white flour and water (A – standard), white flour and milk (cake B), whole flour and water (cake C) and whole flour and milk (cake D). Total proteins were determined by the Kjeldahl method. Soluble proteins (albumins + globulins) and insoluble proteins (prolamins + glutelins) were extracted according to Osborne and quantified by Lowry. Total protein ranged from 6.6-8.1%; soluble protein 1.7-2.7% and insoluble protein 2.1-3.7%. The use of whole flour increased the total, soluble and insoluble proteins in the cakes. Replacement of water for milk did not affect total protein content between A and B cakes, and C and D cakes (p>0.05). Protein solubility was affected mainly in C and D cakes (p<0.05). All cakes had different behaviours regarding insoluble proteins (p<0.05). These results showed that the degree of milling of the flours is more important than total protein content. Profile of soluble and insoluble proteins showed an increase of about 59% and 76%, respectively, when milk and whole flour are combined in the formulation. It is important to consider this behaviour to infer optimum protein content in a diet.