Transport of amino acids from in vitro digested legume proteins or casein in Caco-2 cell cultures.

Purified legume storage proteins (chickpea 11S and 7S globulins, faba bean globulins, and lupin globulins) and casein (casein) were subjected to an in vitro enzyme (pepsin + pancreatin) digestion process. Protein digests were then used in a bicameral Caco-2 cell culture system to determine amino acid transport across the cell monolayer. With digests from legume proteins, absolute amounts of aspartate, glycine, and arginine transported were higher than those found in digested casein, whereas amounts of glutamate, proline, tyrosine, valine, and lysine were lower. However, proportions of amino acids in the basolateral chamber as compared with amounts added in the apical chamber were lower than casein controls for all amino acids except cystine. Results confirm previous in vivo observations that amino acids from legume proteins are probably absorbed at rates different from those in other proteins of animal origin such as casein.