Pectin and its acid hydrolysate for the modification of hydration, pasting, thermal and rheological properties of barley starch.

The influence of native pectin (NP) and its hydrolysate (PH) in modifying hydration, thermal, pasting, rheological and textural properties of barley starch was assessed. The addition of NP and PH significantly modified the hydration properties of barley starch. The swelling and solubility of barley starch increased in the presence of NP while PH decreased it in a concentration dependent manner. The differential scanning calorimetry results showed that gelatinization temperatures increased in the presence of NP/PH whereas decrease in enthalpy was observed. In addition, only NP was found effective in increasing peak viscosity of the barley starch during pasting while PH decreased it. PH was observed to be more efficient in terms of reducing setback and final viscosity. Moreover, the NP addition caused an increase in magnitude of G' and G" while lower values were obtained with PH suggesting an increase in the elasticity of barley starch pastes with NP and an increased viscous behavior in case of PH. This was further confirmed by scanning electron microscopy which revealed interconnected flakes network in starch pastes containing NP. Overall these results revealed that molecular weight and concentration of pectin played an important role in modifying starch functional properties.