Effect of processing on the content of β-N-oxalyl-α, β-diaminopropionic acid (gb-ODAP) in grass pea (Lathyrus sativus) seeds and flour as determined by flow injection analysis

The effect of cooking, roasting, autoclaving and fermentation on the content of β-ODAP in the whole seeds and flour of grass pea (Lathyrus sativus) were studied at different levels of temperature, time, pH, degree of soaking and moisture content. The method of determination used was flow injection analysis, with immobilised glutamate oxidase and horseradish peroxidase. The whole seeds flour was found to contain about 922 mg 100g−1 β-ODAP in dry weight basis. The reduction of β-ODAP content, in samples which were cooked for 60min and roasted (150 °C for 60min) was 57% and 82%, respectively. The content of β-ODAP in dry seeds autoclaved for 30 min also showed a significant (p = 0.05) reduction by 39%, as compared to that of raw whole seeds. Similarly, by cooking of presoaked seeds the content of β-ODAP was reduced by up to 67%. Neither the back-slopped fermentation process nor the spontaneous fermentation were effective in reducing the content of β-ODAP. Whereas roasting and autoclaving of the milled samples caused significant (p = 0.05) reduction in the content of β-ODAP up to 30% and 50%, respectively, compared to that of raw whole seeds.