Impact of tamarind seed gum on the viscosity behavior, thermal properties, and extrusion characteristics of native corn starch

Tamarind seed gum (TSG) is a cold‐swelling hydrocolloid with remarkable processing stability and starch synergy. Its use in direct expanded extruded foods has not been documented. The thermal and pasting viscosity properties of six TSG (0%, 0.5%, 1.0%, 2.5%, 5.0%, and 7.5% TSG) and native corn starch blends were characterized by differential scanning calorimetry and ViscoQuick, respectively. These same blends were extruded using a corotating twin‐screw extruder at four screw speeds (SSs) (150, 300, 450, and 600 rpm). System back pressure, motor torque, and specific mechanical energy (SME) were measured. Extrudate quality metrics, such as expansion ratio (ER), water absorption index (WAI), and water solubility index (WSI), were also measured. The pasting viscosities indicated that TSG inclusion increases viscosity but also makes the starch‐gum paste more susceptible to permanent shear degradation. The thermal analysis indicated that TSG inclusion narrowed the melting endotherms and lowered the energy required for melting (p