Firmness, seed wholeness and water uptake during the cooking of lentils (Lens culinaris cv. anicia) for 'sous vide' and catering preparations

The study aimed to optimize cooking conditions of lentils (Lens culinaris cv. anicia) for 'sous vide' processing and catering. The softening rate of lentil seeds during cooking in deionized water was consistent with two simultaneous first order mechanisms. The apparent activation energies of firmness breakdown and loss of integrity were 86.5 kJ mol-1 and 271.3 kJ mol-1, respectively. Wholeness of the lentils was better preserved when the cooking temperature did not exceed 90 degrees C. The loss of firmness was a consequence of hydration of the seed since the regression coefficient between the logarithm of residual firmness and water uptake reached -0.93 regardless of cooking temperature and heating medium (steam or water). Thus, lentil seeds maintained their firmness and wholeness as required for 'sous vide' and catering if they were cooked below 90 degrees C for up to 2 h. Higher temperature or longer cooking time resulted in loss of firmness and wholeness.