Understanding the structural contributions to the functional properties of chestnut starch high in resistant starch type-2.

Abstract

Chestnut has recently attracted attention because of its exceptional functional properties, which are mainly influenced by the structural properties of chestnut starch (CS). In this study, ten varieties of chestnut from the northern, southern, eastern, and western regions of China were selected, and their functional properties, including thermal properties, pasting properties, in vitro digestibility, and multi-scale structural characteristics were characterized. The relationship between structure and functional properties was clarified. In the varieties that were studied, the pasting temperature of CS was in the range of 67.2-75.2 °C and the pastes displayed diverse viscosity characteristics. Slowly digestible starch (SDS), and resistant starch (RS) of CS were in the range of 17.17-28.78% and 61.19-76.10%, respectively. Chestnut starch from north-eastern China exhibited the highest RS content of 74.43-76.10%. Structural correlation analysis revealed that smaller size distribution, fewer B2 chains, and thinner lamellae thickness contributed to higher RS content. Meanwhile, CS with smaller granules, more B2 chains, and thicker amorphous lamellae displayed lower peak viscosities, stronger resistance to shear, and higher thermal stability. Overall, this study clarified the relationship between the functional properties and the multi-scale structure of CS, revealing the structural contributions to its high RS content. These findings provide significant information and basic data for use in the creation of nutritional chestnut food. © 2023 Society of Chemical Industry.