Thermal isomerisation of β-N-oxalyl-L-α, β-diaminopropionic acid, the neurotoxin in Lathyrus sativus, during cooking

The naturally occurring β-form of N-oxalyldiaminopropionic acid (β-ODAP) present in Lathyrus sativus is the main neurotoxic principle implicated in neurolathyrism. The α-form of ODAP has been shown to be less toxic to experimental animals. Therefore, the extent of isomerisation of the toxin from the β-form to the α-form during cooking might determine the toxicity of L. sativus seed. sults of the present study reveal that there is a temperature- and time-dependent isomerisation of the β-form to the α-form. The extent of conversion of β-ODAP to its α-form was determined in some common Indian cooking preparations and was found not to exceed 40%. It seems likely that the toxicity of L. sativus seed due to β-ODAP is only partially removed during cooking and that a significant proportion of the toxin (about 60%) remains as the toxic β-form.