In vitro digestibility, pasting, and thermal properties of Arenga pinnata (Wurmb.) Merr starch citrate

This study aims to prepare citrate-esterified Arenga pinnata (Wurmb.) Merr starch (APS) with different degrees of substitution (DS [0, 0.02, 0.24, 0.40]) and evaluate in vitro digestibility, pasting, and thermal properties of citrate APS. The citrate APS surface become rougher. Citric acid modification led to significant changes in molecular and crystal structure citric acid treatment significantly reduced molecular weight of APS, and the molecular weight was decreased with increasing the DS. The citrate APS possessed a lower pasting viscosity and a higher resistant starch (RS) content. RS content of APS citrate was increased with increasing the DS, and the maximum RS content reached 74.21%. Citric acid modification improved thermal stability of the APS. These results suggested that the structural alterations might be responsible for changes of APS citrate properties and the citrate APS was an excellent potential food additive that had desirable functional properties and high RS content. Novelty impact statement The non-conventional APS was modified using citric acid. The citrate APS possessed a lower pasting viscosity and had a higher RS content, up to 74.21%. The citrate APS had a higher thermal stability.

Automated summary

This study aimed to modify Arenga pinnata starch using citric acid and evaluate its properties. The citrate-esterified APS showed changes in molecular and crystal structure, reduced molecular weight, lower pasting viscosity, higher resistant starch content, and improved thermal stability. The results suggest that citrate-esterified APS has desirable functional properties and high resistant starch content, making it a potential food additive.