Abstract:
The infrared heating of preconditioned cowpea improves its utilization and potential application
in food systems. This study investigated the effect of optimizing preconditioning and infrared
heating parameters of temperature and time on cooking characteristics of precooked cowpeas using
response surface methodology (RSM). The moisture level (32–57%), infrared heating temperature
(114–185 C), and time of processing the seeds (2–18 min) were optimized using a randomized
central composite design to achieve optimal characteristics for bulk density and water absorption. A
second-order polynomial regression model was fitted to the obtained data, and the fitted model was
used to compute the multi-response optimum processing conditions, which were the moisture of
45%, the heating temperature of 185 C, and time of 5 min. Precooked cowpea seeds from optimized
conditions had a 19% increase in pectin solubility. The total phenolic and total flavonoid contents
were significantly reduced through complexation of the seeds’ phenolic compounds with other
macromolecules but nonetheless exhibited antioxidant properties capable of scavenging free radicals.
There was also a significant reduction in phytate and oxalates by 24% and 42%, respectively, which
was due to the heat causing the inactivation of these antinutrients. The obtained optimized conditions
are adequate in the production of precooked cowpea seeds with improved quality.
