Cooked Yield and True Nutrient Retention Values of Selected Commonly Consumed Staple Foods in South-west Nigeria
There is a dearth of information on nutrient data for cooked/ prepared foods and their nutrient retention factors in Nigeria. This study determined the cooked yield and nutrient retention factors of commonly consumed staple foods in South-West Nigeria. Proximate and mineral analysis were carried out on the raw and the cooked samples of the following staple foods: Fermented Cassava Flour (elubo lafun in Yoruba) (FCF), Yam Flour (elubo isu in Yoruba) (YF), Garri (Gr), Cowpea (CwP) and Rice (Rc). Cooked yield and true retention values of the nutrients analysed were also calculated. Crude protein content in raw samples was highest in CwP (33.5g/100g), metabolisable energy ranged from 342.3 kcal/100g in CwP to 350.0 kcal/100g in Rc; calcium and iron content was highest in Gr. In the cooked samples, crude protein ranged from 0.2g/100g in Gr to 9.3g/100g in CwP, metabolisable energy ranged from 101.5 kcal/100g in Gr to 119.2 kcal/100 g in CwP, calcium content was between 3.3 mg/100 g in CwP to 18.8mg/100g in Gr, and iron content ranged from 0.5mg/100g in Rc to 1.1 mg/100 g in Gr. The cooked yield factor ranged from 2.9 in CwP to 4.0 in Rc; percentage true retention of the nutrients in the samples were: crude protein 31.9% in Gr to 142.5% in Rc; calcium 53.0% in YF to 111.7% in FCF; iron, 58.2% in YF to 119.7% in CwP. The present study serves as a baseline for studies that focus on nutrient retention values of staple foods consumed in Nigeria and other developing countries.
Keywords: Nutrient retention, nutrient content, food composition, cooked yield, prepared foods