Effects of milling sorghum into fractions on yield, nutrient composition, and their performance in extrusion of dog food

The pet food market has grown steadily in part through introduction of novel ingredients. Whole sorghum has been used frequently, but more novelty and nutritional value may be derived if sorghum flour or bran were considered separately. Therefore, the objective of this research was to produce and evaluate sorghum fractions for use in a pet food. A locally grown red sorghum was purchased and milled into different fractions that were later incorporated into extruded dog foods. Yields of flour, mill-feed and germ averaged 69.2%, 28.5% and 0.79%, respectively. Four diets were produced by extrusion: a whole sorghum (WSD), sorghum flour (FLD), sorghum mill-feed (MFD), and control (CON) with equal parts corn, rice and wheat in a completely randomized design experiment. The FLD had the greatest (P < 0.05) expansion and was 1.92-fold more than MFD and 1.35-fold more than WSD. FLD and MFD kibbles were harder (P < 0.05), and CON and WSD were similar to MFD. The diet with higher bran content (MFD) did not expand as well; and diets containing sorghum flour, whole sorghum and the control diet were more stable during processing. Milling sorghum into flour and mill-feed produced quality kibbles for feeding to dogs.