The effect of decortication and extrusion on the digestibility of sorghum by preschool children

Abstract

The effect of decortication and extrusion on the apparent protein quality and digestibility of sorghum (S. vulgare) was evaluated in comparative balance studies in nine children 7-24 months of age. Sorghum provided (as kilocalories) 8% protein and 62% carbohydrate in the study diet. Lysine was supplemented to 3% of protein. Casein provided 6.4% protein kilocalories in the control diet. A mixture of sucrose, dextrimaltose and cornstarch provided carbohydrate. Both diets contained 30% fat kilocalories as soybean-cottonseed oil blend. Balance studies were carried out during the last 6 days of three 9-day dietary periods: control-sorghum-control. Apparent N absorption from sorghum was 81 +/- 4% and did not differ from control. Apparent N retention, 21 +/- 6%, was expectedly lower than the preceeding control (27 +/- 8%, P less than 0.05) and following control (33 +/- 7%, P less than 0.01) values. The control values differed significantly from each other (P less than 0.05). Fecal weights and energy losses showed only minor differences between the two diets. These data contrast sharply with previous results obtained with whole-grain sorghum and suggest that the use of decortication and low cost extrusion processing can markedly improve the apparent protein quality and digestibility of sorghum.