Protein quality and digestibility of different parts (spathe and spadix) of Colocasia esculenta var. antiquorum flower

Abstract

A rat growth and balance study was conducted to determine the protein quality and digestibility of the cooked spathe and spadix. Twenty-four (24) weanling male wistar rats were distributed in four groups of six elements. Test groups received respectively spathe- based, spadix-based and spadix + spathe-based diets. Each protein product was fed as the sole source of 10% dietary protein. The evaluated biological parameters were protein efficiency ratio (PER), net protein ratio (NPR) and true protein digestibility (TPD). The cooked spadix contained higher values of crude lipid (10.8% DM), crude protein (18.73% DM), and crude fibre (34.47% DM) while spathe had higher values of crude ash (9.26% DM), cellulose (8.20% DM), phytate (0.06 mg/100 g DM), cyanide (0.25 mg/100 g DM) and total oxalate (880.0 mg/100 g DM). Spathe showed significantly (p < 0.05) a
lower PER (1.00), NPR (1.42) and TPD (53.00%) compared to spadix. Spadix+ spathe mixture showed the highest values of PER (1.76), NPR (2.11) and TPD (60.72%) compared to spathe and spadix separately, though there was no significant difference (p > 0.05) between the TPD of spadix and spadix + spathe mixture. The presence of higher levels of cellulose, phytate and hydrocyanide in spathe could have been responsible for the lower protein digestibility and quality observed.

Keywords: Colocosia esculenta, cocoyam, cooked spadix, cooked spathe, PER, NPR, TPD.