MEETING ABSTRACT

P-187
Extrusion of whole-grain and milled specialty sorghums
Presenter: A. Perez-Gonzalez, Texas A&M Univ
Co-Author(s): C. McDonough, Texas A&M Univ; M. Riaz, Texas A&M Univ; L. Rooney, Texas A&M Univ

White food-type sorghum produces excellent foods. High-tannin (HT) sorghums will increase their antioxidant and dietary fiber contents. The objective was to evaluate the influence of genotype, milling methods (cracking, decortication, or intact grain), and tempering moisture (MC) on the performance of specialty sorghums in high-temperature short-time (HTST) extrusion. HT and waxy, heterowaxy and nonwaxy white sorghums were milled by the three methods and tempered to 14% MC. HT sorghum was also tempered to 13% MC. Extrudates of acceptable quality were produced from intact whole grains of all sorghum types tested. Interactions between MC and milling method of HT sorghum were observed for all variables measured except for bulk density (DEN). The best extrudates were obtained by tempering decorticated grain to 14% MC. These products had a DEN of 47.9 g/L, the highest expansion ratio (EXP = 4.4), and the lowest force to break in a Kramer press (FOR = 388 N). Specific mechanical energy (SME) was 503.9 KJ/Kg and feed rate (FR) was 180 Kg/h. Sensory texture was also the best among the HT treatments (good crunchiness, soft texture) and taste was slightly bitter. Interactions between genotype and milling method of the white sorghums were observed for all variables. The best extrudates were prepared by cracking the waxy grain. These products had a DEN of 93.9 g/L, an EXP of 3.5, and a FOR of 404 N. SME was 382.2 KJ/Kg and FR was 174 Kg/h. Sensory texture was very good and taste was bland. Milling of sorghum grains prior to extrusion enhanced the quality, but possibly decreased the nutraceutical value (less fiber and/or antioxidants) of the end-products as compared to those from intact whole-grains. Careful processing is needed to optimize both quality and nutraceutical value.