Effect of soy protein supplementation on the nutritive value of ‘gari’ (farina) from Manihot esculenta

Abstract

The supplementary role of soy protein on cassava ( Manihot esculenta ) “gari” or farina was studied in 35 day-old albino rats of the Wistar strain ( n =6 per group) for 10 days. Gari was supplemented with soy beans at 10 and 15% soy protein levels to produce “soy gari” and the performances of rats fed the test diets compared with those on a 10% casein diet. Protein efficiency ratio (PER), Net protein utilization (NPU), true digestibility (TD) and biological values (BV) were the parameters used to assess the nutritional performance of the diets based on weight gains and nitrogen balance. The PER for 10% casein, 10 and 15% soy protein-supplemented gari groups were 2.31, 1.85 and 1.94 respectively, while the corresponding values for NPU were 71.9, 65.8 and 64.1, respectively. The TD values for the 10% casein, 10 and 15% soy protein-fed rats were 97.2, 91.9 and 90.0, respectively, while the corresponding values for BV were 73.9, 70.9 and 71.5. The PER, NPU, TD and BV for 10% casein diet were significantly superior ( P <0.05) to those of the soy gari diets which gave NPU, TD and BV values 89–97% of those of the casein diet. There were no significant differences ( P >0.05) in these parameters between the 10 and 15% soy protein supplementation. Soy gari is safe to the consumer, because the procedures involved in processing soy beans and cassava ensure the elimination of toxic anti-nutritional factors known to impact negatively on nutrient availability, metabolic processes and growth. It is suggested that the consumption of soy gari at 10% soy protein supplementation be promoted in gari-eating areas, to ameliorate the endemic problems of protein deficiency disorders.