The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASABE meeting paper. EXAMPLE: Author's Last Name, Initials. 2008. Title of Presentation. ASABE Paper No. 08----. St. Joseph, Mich.: ASABE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASABE at rutter@asabe.org or 269-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA). An ASABE Meeting Presentation Paper Number: 084454 Effect of Grain Sorghum Protein Digestibility on Starch Gelatinization and Enzymatic Conversion to Glucose Joan R. Hernandez, Graduate Research Assistant Biological and Agricultural Engineering Department, Texas A&M University, College Station, Texas 77843, E-mail: joan_che98@tamu.edu. Sergio C. Capareda, Assistant Professor Biological and Agricultural Engineering Department, Texas A&M University, College Station, Texas 77843, E-mail: scapareda@tamu.edu. Dirk B. Hays, Assistant Professor Cereal Grain Developmental Genetics Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843, E-mail: dbhays@tamu.edu. Ostilio R. Portillo, Graduate Research Assistant Department of Soil & Crop Sciences, Texas A&M University Affiliation, College Station, Texas 77843. E-mail: OPortillo@ag.tamu.edu. William L. Rooney, Associate Professor Sorghum Breeding and Genetics Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843. E-mail: wlr@tamu.edu. Written for presentation at the 2008 ASABE Annual International Meeting Sponsored by ASABE Rhode Island Convention Center Providence, Rhode Island June 29 – July 2, 2008 Abstract. The objective of this study is to select the best high digestible grain sorghum (HDGS) lines that breeders have developed for low energy input liquefaction, saccharification and fermentation for bio-ethanol production. The parental lines and offspring generated by crosses of two HD lines (P850029 and P851171) with three wild type (WT) sorghum lines (B.Tx635, R.Tx436 and