Environmental variables affect the hard-to-cook phenomenon of cowpea (Vigna unguiculata) seed.

Changes in moisture content and cooking rate of cowpea (Vigna unguiculata) seeds which were sun-dried for 5 hours on cement, wood, or corrugated iron sheet surfaces and packaged for 6 months in jute or polythene bags were studied. Relationships and effects of interacting variables studied were examined using the contrast analysis technique. From day zero to about 2 months of storage, the sun-dried samples had significantly (p<0.01) lower moisture content and longer cooking times than the corresponding control samples. However, moisture-gain and cooking time increased progressively throughout the storage period for all samples studied. The relationship between these two variables, tested at p = 0.01 using contrast analysis technique, was dependent on the choice of packaging material.