Principles of Biochemistry Volume 3 - A. Lehninger 1985

Selected Aspects of Human Biochemistry
Human Nutrition
Certain plant proteins in food can be mutually complementary

Although plant Proteins are generally inferior in nutritional value to animal proteins, a proper combination of plant proteins can nevertheless provide the body with a complete and balanced amino acid profile. For instance, corn proteins are low in Lysine but contain sufficient amounts of Tryptophan, whereas bean proteins are rich in lysine but deficient in tryptophan. Individually, neither of these Proteins can be considered “good.” However, a mixture of beans and corn provides the Essential Amino Acids in amounts required by The Human Body. Such a mixture, known as succotash (a dish made of corn and beans), was intuitively “discovered” by the Native Americans of the New World. Consuming only beans for breakfast and only corn for lunch separately would inevitably disrupt this beneficial combination of plant proteins. Eastern cultures have also learned to combine certain plant-based foods to achieve a nutritionally complete amino acid mixture, a classic example being the combination of rice and soybeans. In Central and South America, where dietary Protein deficiency has been common, an international Nutrition committee introduced a complete nutritional blend known as “Incaparina,” which contains relatively inexpensive plant proteins, primarily derived from corn, sorghum, and cotton plants. While each of these components has a low nutritional value on its own, together they form a protein blend equivalent in nutritional value to milk protein.