The effects of tumbling and sodium tripolyphosphate on the proteins of doner

This study was designed to investigate the influence of tumbling and sodium tripolyphosphate (STPP) with marination on the protein structure of raw and cooked doner, a traditional Middle East product consumed widely in many areas of the world. Proximate composition (%moisture, %protein, %fat, %ash, and pH value), salt soluble protein (SSP) and total a-amino grup amount were determined. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to investigate alterations in the sarcoplasmic and myofibrillar proteins. Utilization of STPP increased the moisture content and ash contents, and pH value of raw doner (p<0.05). Only tumbling and STPP had a significant two-way interaction for moisture content, SSP and total a-amino group amounts of cooked doner (p<0.05). None of the treatments significantly affected the fraction of sarcoplasmic and myofibrillar proteins. In addition, cooking caused proteolysis of these proteins. (C) 2011 Elsevier Ltd. All rights reserved.