The Supplementary Protein Value of Peanut Flour

In 1920 Johns and Finks’ reported a series of experiments whose results suggested the desirability of utilizing peanut flour as a supplement to wheat flour. In this article they state: “Bread made with a mixture of 25 parts of peanut flour and 75 parts of wheat flour 174 per cent extraction] furnished adequate proteins and water-soluble vitamine for normal growth.” These authors had previously shown2 that the principal proteins of the peanut are two globulins to which they have given the names of arachin and conarachin and that these proteins are particularly rich in the basic nitrogen that is so lacking in wheat flour proteins. Their findings in this respect are given in Table I. The value of peanut flour as a nutritive product was also demonstrated in 1918 by Daniels and Loughlin.3 These investigators reported that a purified food mixture, yielding 18 per cent protein and composed of 67.5 gm. of peanut meal plus 10 gm. of lard, 5 gm. of butter fat, 11.4 gm. of starch, and 5.09 gm. of suitable inorganic materials, was in every way adequate for normal growth and reproduction of rats. In 1919, and again in 1921, McCollum, Simmonds, and Parsons4 called at.tention to a method of comparing the supplementary protein value of foodstuffs. In the earlier paper they maintained that it was possible to secure normal growth with an otherwise adequate diet if the protein content was as low as 9 per cent provided that the quality of the protein was high. Making use of this method the later papers detail an extended application of the method to foodstuffs. The following quotation from the 1921 papers summarizes their findings in part: “ . . . kidney, liver, and muscle proteins have much greater values as supplements to the