Effect of cooking on thiamin retention in cowpea (Vigna unguiculata)

The thiamin content determined in the cultivars of cowpea (Vigna unguiculata) seeds ranged from 0.61 to 1.08 mg/100 g with a mean value of 0.86 +/- 0.2 mg/100 g. The Lhiamin levels of varieties "Tvu 57", "Tvu 17" and "Tvu 76" were higher than that of others whereas, "Tvu 4557" had the lowest value (0.61 mg/100 g). The cooking methods affected the levels of thiamin differently. Trona created an alkaline cooking medium for the cowpeas and it led to a greater loss of thiamin (76.7-97.4%); with the slow cooker 88.8% loss was obtained while the pressure cooker Caused a loss of 73.6%. A higher level of thiamin (71.7%) was retained in moin-moin. The result suggests caution on the use of irona for the traditional cooking of cowpea menu.