Physicochemical properties and digestion characteristics of acylated Arenga pinnata starches

Summary This study aims to investigate influences of different acylations (acetyl, propionyl and butyryl) with different degrees of substitution (DS) on physicochemical properties and digestion characteristics of Arenga pinnata starches (APS). The presence of acyl protons was confirmed by 1 H NMR and FT-IR spectroscopy of acylated APS. The viscosities, swelling power, thermal properties and crystallinity of acylated APS were lower than APS, but these characteristics tended to increase with the increase of DS. Acylation could effectively regulate the digestibility of starch granules. The content of resistant starch in acylated APS increased from 66.58% to 80.92%. With the DS increasing, acylation strengthened the rearrangement and aggregation behaviour of APS molecular chains, making the crystal structure and double helix structure of amylopectin crystal region more orderly, which might lead to changes in the pasting properties and digestibility. It was possible to evaluate the effectiveness of low-substituted acylated APS.