Nutritional Quality of Drum-processed and Extruded Composite Supplementary Foods

摘要

This study was conducted to evaluate the nutritional quality of ready-to-eat composite foods intended for supplementary feeding of preschool age children in Tanzania. Four supplementary foods, namely, corn-bean-sardine meal (CBSM), bean meal (BM), sorghum-bean-sardine meal (SBSM), and rice-bean-sar-dine meal (RBSM) were formulated according to the FAO/WHO/UNU guidelines. The food mixtures were extruded, drum-processed, and cooked conventionally in the traditional way. Cooking doneness was evaluated by percent starch gelatinization and residual urease activity; biological qualities—true protein digestibility and growth performance—were evaluated using Sprague Dawley weanling rats. Efficiency in destroy-ing phytohemagglutinins and the antinutritional factors, trypsin, chymotrypsin, and α-amylase inhibitors, were also evaluated. Results of the study showed that starch gelatinization and residual urease activity were not significantly different (P > 0.05) between the extruded and drum-processed diets. Relative to conventional cooking, starch gelatinization was 95% to 100% in extruded and 90% to 100% in drum-processed products. Inactivation of urease activity ranged from 93% to 100% in extruded and 83% to 100% in drum-processed diets. The true protein digestibilities were significantly (P ≦ 0.05) higher when extruded foods, compared with drum-processed and conventionally cooked foods, were fed to experimental animals. Animals fed extruded products gained more weight relative to those fed drum-processed and conventionally cooked foods. Destruction of phytohemagglutinins ranged between 91% to 97% in extruded and between 90% to 95% in the conventionally cooked and drum-processed foods. Extrusion, drum processing, and conventional cooking also resulted in significant destruction of the antinutritional factors trypsin, chymotrypsin, and α-amylase inhibitors. These results suggest that extrusion and drum processing of cereal-bean-sardine composite foods result in products meeting the required nutritional quality.