The Egg-Replacement Value of the Proteins of Cereal Breakfast Foods, with a Consideration of Heat Injury
John R. Murlin,
Edmund S. Nasset and
M. Elizabeth Marsh
Department of Vital Economics, University of Rochester, Rochester, New York
1. A 10-week diet experiment on ten young men was carried outin 5-day periods in order to compare the nutritional value ofthe proteins of seven cereal breakfast foods with egg protein.Diets contained 5% of the calories in the form of protein, approximately45% in the form of carbohydrate and 50% in the form of fat.Egg or cereal protein supplied 78% of the total nitrogen, creamand butter 11% and fruit and other accessory foods such as lettuceand a vitamin B complex tablet the remaining 11%.
2. Cerealprotein alternated every 5 days with egg protein.One half ofthe diet squad ate the cereals in a certain order,the otherhalf in reverse order. This served to balance whateverprogressivechange in the tendency to retain nitrogen mightresult fromlong-continued sustenance on low protein. The averagelevelof nitrogen intake for all subjects was 5.92 gm., theegg periodalways equalling the following cereal period.
3. Replacementof egg protein by cereal protein is calculatedby dividing thedifference in nitrogen balance on the two dietsby the amountof egg nitrogen fed. This difference expressedas a percentageis then subtracted from 100 to find the extent(in percentage)to which cereal replaces egg.
4. Biological valuealso was calculated takingegg as standard. The difference betweenfecal nitrogen on cerealand egg is subtracted from food nitrogento give absorbednitrogen. The difference betweencereal and egg urinarynitrogen then is found and expressedas a percentage of theabsorbed nitrogen. This value subtractedfrom100 gives (as apercentage) the extent to which the cerealprotein absorbedreplaces egg protein in the metabolism of thebody.
5. A whole grain oats had the highest replacement andbiologicalvalues, 87 and 98, respectively. Awheat endosperm product gavethe next highest R.V. (72) followedby a granulated wholewheat supplemented withwheat germ (70), torn (shredded)whole wheat (68), toasted wholewheat (64), flakedwhole wheat (63) and inflated (puffed)wheat (57).In the B.V. scale, oats was followed by the tornwheat (92.8),toasted whole wheat (90), granulatedwheat (88.7),flaked wheat (82.1), inflated wheat (79.8) andwheat endosperum(79.7).
6. The lower rank of the flaked andinflated whole wheats inboth scales is believed to be accountedfor by the high heatto which they are subjected in the processof manufacture. Digestibilitywas not diminished.