alpha-amylase inhibitors in cowpea (Vigna unguiculata): effects of soaking and cooking methods.

The effects of certain cooking and soaking methods on cowpea (Vigna unguiculata (L.) Walp.) ?-amylase inhibitors were studied. The following ways of cooking were investigated: boiling in distilled water, autoclaving and cooking in a microwave oven. Soaking was done in water and alkaline solutions. Cooking was found to be ineffective in reducing amylase inhibitor activity except for autoclaving. Soaking in alkaline solutions under different conditions achieved 10-47% reductions of these anti-nutrients. The most pronounced decrease of amylase inhibitor (55%) was observed when soaked seeds were boiled. A marked increase of anti-amylasic activity was observed when seeds were submitted to extensive cooking. No such increase was shown in samples cooked in a microwave oven.