Effect of processing methods on the trypsin inhibitor,tannins, phytic acid and ODAP contents of grass pea seeds

Abstract

Grass pea seeds were given different treatments including cooking boiling, autoclaving, dry heating and fermentation into tempeh. Changes in the levels of the antinutritional factors due to the treatments were estimated. Dry heat treatment completely eliminated phytic acid and greatly reduced tannins, trypsin inhibitor activity and ODAP (100%,64%,87.4% and 75%, respectively). Cooking reduced tannins (74%), trypsin inhibitory activity (81 %) and ODAP (77%) while phytic acid was less affected (59.4%). Autoclaving had the most pronounced lowering effect on trypsin inhibitor activity (91 %), whereas other anti-nutritional factors were less affected. Boiling also decreased the trypsin inhibitor activity by 89.3%. Preprocessing of grass pea for tempeh fermentation and fermentation into tempeh significantly removed large portions of the antinutritional factors in grass pea.