Résumé
Boiled yam preparation steps showed variations in the yam pieces size and the cooking operation; this presumably affect the sensory descriptors and texture analyses of final product. In this context, a robust methodology for boiled yam preparation and texture analyses was established. Five varieties were selected based on their contrasting quality characteristics. The optimum cooking time (OCT) for each variety and the ideal cooking time (ICT) defined as fixed duration from OCT of range of varieties were determined. Yam tuber was cut into three equal sections: proximal, central and distal. After peeling and washing, each usable/operational part (6/10) is divided following the length into two subsections (semi-cylinders). The semi-cylinders were steam-cooked up to minimum of 20 min (T20), and thereafter, softness was checked every 5 min using a fork by the panellists. The time when all panellists reported that the pieces are at least fairly soft is defined as OCT. The ICT was determined by calculating the average value of OCT. The latter is used to steam cook the samples evaluated by sensory profiling using quantitative descriptive analysis. In addition, these five varieties were tested at 45 °C by penetration test and texture profile analysis using conical probe P/40C and compression plate (P/75). For both texture methods, the yam pieces were steam-cooked during T20 and OCT. In total, sixty samples were analyzed by section for preliminary tests while forty five samples were used for validated method.