Influence of high-speed jet on solubility, rheological properties, morphology and crystalline structure of rice starch

Influences of high speed jet (HSJ) treatment on solubility, rheological characteristics, morphology, and crystalline structure of indica rice starch were investigated. The solubility of indica rice starch was improved significantly from 1.34 to 32.4%. Dynamic oscillation analysis revealed that HSJ treatment significantly altered the viscoelasticity of rice starch. During a dynamic frequency sweep, G'(20) (Hz) was decreased from 3382 to 268 Pa, indicating that HSJ treatment had a great influence on the elasticity of the resulting rice starch gel. Scanning electron microscopy (SEM) showed that rice starch granules lost their integrity. X-ray diffraction (XRD) analysis revealed that, upon HSJ treatment, rice starch lost it A-type crystalline structure and became amorphous. Differential scanning calorimetry (DSC) analysis showed a decrease in onset temperatures (T-0) and gelatinization enthalpies (Delta H) and on increase in peak temperatures (T-p). The results indicated that the HSJ treatment is an effective technique for improving rice starch solubility and altering its rheological properties.