Viscoelastic characteristics of kpejigaou: a griddled cowpea food

Abstract

The viscoelastic properties of kpejigaou were evaluated, with the goal of standardizing the process. A factorial design with temperature (130, 200 and 270C) and time (5, 7.5 and 10 min) was followed to process kpejigaou. Griddled samples were subjected to compression–relaxation tests using a TA-XT2 Texture Analyzer. Kpejigaou exhibited the properties of viscoelastic solid material at all griddling conditions. The generalized Maxwell and Peleg–Normand models showed the most satisfactory fit (R2 > 98%) to stress data. Products made at higher griddling temperatures for longer times experienced higher moisture loss, were more rigid and dissipated energy at a faster rate. The stress–relaxation time was inversely correlated with moisture loss (r = -0.91, P < 0.05) and viscosity (r = -0.85, P < 0.01). The viscoelastic behaviour of kpejigaou could be related to the spongy and porous structure of kpejigaou, starch gelatinization and the rate of moisture loss during griddling. Griddling temperature of 170C for 6 min could be recommended for the production of firm and spongy kpejigaou acceptable to the consumers