Crop ash filtrate influence on cooking time and sensory preferences for dried black beans (Phaseolus vulgaris L.)

Filtrate made from the burnt ash of crop plant residue is used in cooking in Northern Uganda. This practice is believed to decrease the cooking time of hard-to-cook legumes and provide a culturally preferred taste. The objectives of this study were to: (1) compare cooking times and sensory preferences for dried black beans (Phaseolus vulgaris L.) among four treatments: plain water (control), table salt, crude ground salt, and ash filtrate; and (2) determine demographic factors (gender, age, and education) that may also influence preferences. Sensory preferences for beans cooked across the treatments were evaluated through blind taste tests. Analysis of variance (ANOVA) with post-hoc Bonferroni multiple comparisons showed a statistically significant (p < 0.01) 27% reduction in cooking time with the addition of ground salt and 18% shorter cook time with ash filtrate. Contrary to anecdotal belief, participants showed an overall preference for black beans cooked with ground salt and table salt over plain beans or those cooked with ash filtrate. The type of treatment and study site significantly (p<0.05) impacted sensory scores. Demographic factors did not influence sensory preferences within or between communities, suggesting that cultural preference for the use of ash filtrate is being influenced by more than actual taste. The reduction in cooking time has important implications for fuel wood requirements as the majority of households rely on fires for cooking.