Characteristics of starch separated from coarse and fine flour fractions obtained from hard, medium-hard, and soft Indian wheat cultivars

Starches from coarse flour (CF) and fine flour (FF) fractions obtained from flours milled from fifteen different wheat cultivars with varying hardness index were evaluated for granules-size distribution, pasting and thermal properties. Grain hardness index of softer, medium-hard and hard wheat cultivars ranged from 66 to 72, 74 to 79, and 80 to 90, respectively. The amylose content of starch from softer wheat cultivars was significantly lower than that from medium-hard and hard wheat cultivars. Starches from soft wheat cultivars had a greater proportion of granules of sizes 25 μm and negatively with granules between 5 and 25 μm size. The SP of starches from softer cultivars was higher due to a higher proportion of large-size granules (>25 μm) and lower proportion of amylose content. The mean transitions temperature of starch from FF was higher and the peak viscosity was lower than that from CF. The enthalpy of gelatinization and melting of amylose–lipids complexes during heating and enthalpy of association of amylose–lipids complexes during cooling was higher for starches from cultivars with lower hardness index than those from higher hardness index. Starches from cultivars with lower grain hardness showed lower peak viscosity and vice versa and this was observed to be negatively correlated with the proportion of small granules (0–15 μm).