Effect of Plant Ash on Nutrient Quality and Antioxidant Activity of African Yam Bean Seed Porridge in Relation to Cooking Time

The present study aimed to investigate the nutrient quality, antioxidant\r\nactivity and sensory acceptability of hard-to-cook African yam bean (AYB) seeds\r\ncooked for 5 h\r\n(control) and for 2 h with plant ash. The plant ash were unripe plantain peel\r\nash (UPA), corn cob ash (CCA) and UPA and CCA mixture. Standard methods of\r\nAssociation of Official Analytical Chemists (AOAC) were used for the proximate and mineral analysis, DPPH,\r\nABTS and FRAP assays were used to investigate the antioxidant activity. A\r\ncompletely randomized design with one way analysis of variance (ANOVA) was used\r\nfor data analysis. The results showed that\r\ncooking of AYB seeds for 2 h with 8 g/100mL plant ash solution improved the nutrient contents, antioxidant activity\r\nand sensory scores of the porridge. Higher values of proteins, ash and energy\r\nwere obtained in 8 g/100mL\r\nUPA/CCA and in 8 g/100mL\r\nCCA additives. However, moisture, fat and fibre contents were not affected by\r\nplant ash additives and were higher in 5 h cooked porridge. Cooking with 8 g/100mL plant ash solution\r\nfor 2 h significantly increased mineral elements in the porridge. Phenolic\r\ncompounds (total polyphenols and flavonoids), and antioxidant activity (DPPH,\r\nABTS and FRAP) showed higher values with plant ash additives. This study\r\nreveals that addition of plant ash did not only reduce the cooking time of AYB\r\nseed by 60%, but also improved the nutrient quality, antioxidant activity and\r\nsensory acceptability.