Objective Measurement of Retrogradation in Cooked Rice During Storage

An Instron Universal testing machine and Differential Scanning Calorimetry were used to investigate textural changes in cooked rice during storage. Two cells were used with the Instron for hardness measurement (Ottawa Texture Measuring System and Back Extrusion cells) and one cell for adhesion measurement (adhesion cell). During storage of cooked rice, retrogradation of the starch led to an increase in hardness as well as a decrease in the adhesion of cooked rice. Storage time, temperature and variety significantly influenced the hardness and adhesion of cooked rice. A correlation analysis between methods showed that Instron measurements OTMS and BE correlated better with a correlation coefficient of 0.978 than the two Instron methods and DSC with a correlation coefficient of 0.752.