Research to determine digestible indispensable amino acid scores (DIAAS) for human foods began in 2013. However, more human foods require evaluation, therefore, the objective of the Stein Monogastric Nutrition Laboratory is to determine DIAAS for a variety of raw and processed human foods. To determine DIAAS, growing pigs are surgically fitted with a T-cannula in the distal ileum and randomly allotted to experimental diets. Each diet is fed for 7 d, with the initial 5 d for adaptation to the diet followed by 2 d of ileal digesta collection for 9 h. A nitrogen-free diet is also fed to determine basal endogenous losses of amino acids (AA), enabling the calculation of standardized ileal digestibility and DIAAS for three age groups. For children > 3-y, cereal grains have DIAAS between 25 and 70 with lysine being first limiting. Peas, pistachio nuts, rapeseed protein, and soy protein have DIAAS ranging from 70 to 100 and the first limiting AA is the sulfur containing AA. Milk protein, beef, and pork, generally have DIAAS > 100, regardless of processing method. However, the first limiting AA in animal proteins varies with histidine being first limiting in whey proteins, and leucine, sulfur containing AA, histidine, and valine all observed to be first limiting in beef and pork depending on processing method. In conclusion, animal proteins have DIAAS > 100, which indicates that these proteins may complement lower quality proteins, and as DIAAS for additional proteins become available the protein value of mixed meals can be calculated.
