Optimisation of the Processing Conditions on the Culinary Qualities of Pressure-Cooked Boiled Yam

Abstract

ABSTRACTYam (Dioscorea rotundata) is consumed in various ways. Boiled yam, in particular, has various culinary applications in Africa, but its preparation by conventional cooking consumes time and energy. Pressure cooking offered suitable alternatives but requires careful management of cooking conditions to assure quality. This study optimised cooking condition [thickness of yam slices (1–12 cm), cooking time (5−60 min) and post-cooking resident time (2−15 min)] for the pressure boiling of yam slices on their culinary (texture and absorbed water) and sensory (appearance, texture and taste) qualities. Response surface methodology was used for the study with the aid of the Design Expert Software. Data comparing the proximate and colour qualities of the boiled yam from conventional and pressure-cooked samples was also analysed using Independent sample t-test. Boiled yam produced at verified optimisation solution (3.09 cm, 15.58 min and 3.10 min) compared favourably with that produced by conventional methods as there were no significant (p < 0.05) difference in proximate composition (t = 0.003, df = 12, p = 0.4985, 1-tailed) and colour quality (t = 0.003, df = 12, p = 0.4895, 1-tailed) of pressure-cooked and conventionally cooked boiled yam samples.