comparison of protein value of commercial baby food with homemade baby food and casein standard in rats as the refference point

background and objectives evaluation of protein quality in food is of great importance due to the biological and economical impacts of food proteins. this study has been conducted with the aim of comparing the protein quality of homemade food (mixture of macaroni and soy bean) with commercial baby food (cerelac wheat) using casein as the refference point.   methods this study was conducted on 64 twenty one day old male wistar rats. the rats were divided into 8 groups, and each group was put on a different diet regiments. the diet regiments were as follow: 2 homemade food+cerelac test diet, 1 ccasein+methionine standard diet, 1 protien-free basal diet, 2 test diet, 1 standard diet and 1 basal diet. the purpose of protien-free diet was to evaluate true protien digestability (tpd). net protein ratio (npr) and protien efficiency ratios (per) were investigated by the basal diet. protein intake and increasing of weight were determined for npr and per calculating. nitrogen intake and fecal nitrogen were determined to calculate tpd. comparison of tpd, npr and per among the groups were analyzed by anova and tukey methods.   results tpd values of standard, cerelac and homemade food diets were 92.8±4, 87±8 and 85.4±3.2; npr values were 4.3±0.4, 4.3±0.9, 3.8±0.6; and per values were 3±0.2, 2.5±0.4, 1.7±0.1 respectively. the statistical difference between tpd and per values were significant (p < 0.05), whereas npr differences were insignificant ( p > 0.05).   conclusion these results shows that tpd and per of homemade foods are lower than cerelac while their npr are acceptable