Improving the Digestibility of Lentil Flours and Protein Isolate and Characterization of Their Enzymatically Prepared Hydrolysates

Raw and cooked lentil flours and protein isolate were digested using one-step-multi-enzyme, two-step-sequential multi-enzyme or pre-hydrolyzed with one-step-single-enzyme systems. In vitro protein digestibility values ranged between 22.3 and 94.4%. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed minimal loss of intact protein and more extensive digestion after actinidin and acid-protease pre-hydrolysis, respectively. Size exclusion high-performance liquid chromatography analysis confirmed greater loss of high molecular mass polypeptides after acid-protease pre-hydrolysis compared to the other enzymes. Additional digestion of pre-hydrolyzed samples using trypsin--chymotrypsin-peptidase resulted in further digestion and release of lower molecular mass peptides. The study demonstrates how different processing treatments and the use of enzymes (alone/in combination) influence lentil protein digestion.