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B. M. Kennedy and A. R. Sabiston. Copyright 1960 by the American Association of Cereal Chemists, Inc. The quality of protein was determined in baked wheat products containing varying amounts of milk and whole egg. Protein efficiency ratios for 4-week periods for the unbaked ingredients were: baking-powder biscuits, 2.4; muffins, 2.9; griddlecakes, 3.6; and 4.2 for a cookie mix over a 3-week period. The ratios were about 15% lower when the mixtures were baked. Milk and eggs exerted a considerable supplementary effect, since the determined protein efficiency ratios were more than 60% higher than those calculated from the individual ingredients. White flour is deficient in isoleucine, lysine, methionine and cystine, threonine, tryptophan, and valine when compared with the F. A. O. reference protein. With 76% of the protein from white flour and 24% from milk, calculations showed that isoleucine, threonine, and valine were no longer limiting. Increasing amounts of milk and egg protein increased the protein efficiency ratios. When 52% of the protein was supplied by white flour and the rest by milk and eggs, as in griddlecakes, the protein efficiency ratio was nearly as high as was that for whole egg. Comparison with the reference protein showed this mixture of white flour, milk, and egg protein to be still somewhat low in methionine and cystine and in tryptophan. |
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