Evaluation of Double-modified High Amylose Rice Starch and Applications in Food Models

Rice starch is an important carbohydrate widely used in food and non-food industries. Native rice starch has some drawbacks that prevent direct use. These limitations include poor thermal stability, inadequate gelling properties, a high degree of retrogradation, and syneresis, which exacerbates coagulation/ hardening problems and ultimately results in a reduction in water content. To overcome these limitations, a series of modifications were undertaken to improve the functional characteristics of high-amylose native rice starch through a two-step modification process. Initially, it was subjected to Octenyl Succinic Anhydride (OSA) modification, followed by subsequent cold water granulation and pre-gelatinization. Furthermore, an imitation cheese food model was used to assess the performance of the modified starches. Pre-Gelainized (PG) starch PG-OSA exhibited greater oil/ water absorption capability and improved cold-water solubility compared to both Granular Swelling (GS)-OSA and native OSA. This enhancement was attributed to the fragmentation of its starch granules, leading to increased exposure of hydrophilic and hydrophobic regions. Starch granules of GS-OSA and OSA- native were more intact which restricted the binding capacity. The rheological properties and textural properties of imitation cheese probed the higher elastic properties, melting temperature, and hardness value in the control sample (native OSA starches) followed by PG starches substituted cheese. The gel-sol transition temperature of imitation cheese was used as a quality parameter for the meltability of the cheese. The melting temperature or cross–over temperature (TC) of OSAnative and PG-OSA were higher than GS-OSA. The GS produced more soft cheese compared to PG starch-substituted cheese. These results indicate that the double modification process was performed to produce more tender imitation cheese, highlighting its significance for food processors in achieving the desired quality in imitation cheese production.