The low-substituted propylene oxide etherified plantain ( Musaparadisiaca normalis) starch: Characterization and functional parameters

Abstract

Starch was isolated from unripe plantain fruit and it was chemically modified where it was hydroxypropylated to improve upon the functional properties of native plantain starch. The yield of the starch was ∼19% and molar substitution increased with increase in concentration of propylene oxide. ‘C’ type X-ray diffraction was shown by native plantain starch and many changes were not noticed after hydroxypropylation. The granules were oval or elliptical in shape with 10–20 μm in width and 15–40 μm in length, modification did not bring about major changes in size and shape except partial erosion of the granules. Hydroxypropylation also improved the swelling capacity from ∼20 in native to 90 g/g. Turbidity reduced after hydroxypropylation and increase in molar substitution. Syneresis reduced by 75% with increase in MS. Thermal studies by DSC revealed that all the parameters decreased after this modification. Onset temperature reduced by ∼26%, peak temperature reduced by ∼9%, endset temperature increased by ∼6%, gelatinization temperature range increased by 137%, enthalpy decreased by 38%. Reduction in all parameters were noticed during 3rd and 18th day scan. Enthalpy of retrogradation as well as percentage of retrogradation reduced to a greater extent during the 3rd as well as the 18th day scanning.