Towards a better understanding of the structure-function relationship of chestnut starches

Chestnut starch is of increasing interest for applications in foods but has been studied to a much lesser extent than other food starches. Hence, the structure-function relationships of starches isolated from eight chestnut cultivars were examined. The starch granules were round, oval and conical in shape, with average particle size and amylose content ranging between 7.14 and 9.39 microm and 29.9 to 34.0 %, respectively. Chain length distributions showed larger differences between the starches in the A chains than in the B₁ ∼ B₃ chains. All chestnut starches exhibited a typical B-type crystalline pattern, with the relative crystallinity ranging from 34.1 to 40.6 %. Significant differences were also observed in short-range molecular order and in functional properties. Pearson correlation analyses showed that amylose content was positively correlated with peak and breakdown viscosities and negatively correlated with the rate of in vitro digestion of the starches. The short A chains were negatively and the B₂ or B₃ chains positively correlated with the peak and breakdown viscosities, but the opposite correlations were noted for the rate of in vitro digestion of the starches. This study contributes new insights into an understanding the structure-function relationships of chestnut starches and for their applications in foods.