ABSTRACT
Starch as an agro-sourced polymer has become popular recently due to its wide availability, low cost, and total compostability without toxic residues. This chapter deals with the physicochemical, structural, morphological, thermal, and rheological properties of barley starches. Significant variations were found in the chemical composition (amylose, lipid, protein, ash, and phosphorus-containing compounds) of normal, waxy, and high-amylose barley starches. Barley starch showed a mixture of large (spherical, disc, and lenticular shaped) (waxy type) and small (irregularly shaped) granules (normal and high amylose). The thermal characteristics of starches were determined using differential scanning calorimetry; gelatinization transition temperatures, To (onset), Tp (peak), Tc (endset), and the enthalpy of gelatinization (ΔHgel) are analyzed. The crystalline patterns of barley starches were determined by X-ray diffraction and A-type crystalline patterns were observed, which are a characteristic of cereal starches. Steady and dynamic shear properties were studied using a rheometer. The storage modulus (G′) value for starch pastes was observed more than loss modulus (G′′) and the tan δ (G′′/G′) value of starches was less than 1, indicating their behaviour is more elastic than.
