Structural and functional properties of starches from Chinese chestnuts

Structural and functional properties of starches isolated from four varieties of chestnuts grown in China were characterized in this study. The starch granules exhibited a variety of shapes, varying from round, croissant-like, irregular to triangular. The amylose content of four chestnut starches was about 21–22%. Average particle diameter of the four starches varied between 10.8 and 18.1 μm. The X-ray patterns of four chestnut starches were of C-type, with relative crystallinity ranging between 26 and 29%. Although there were only small differences between the starches in amylose content, they displayed significant variability in physicochemical and functional properties, such as swelling power, pasting characteristics, thermal and textural properties, freeze-thaw stability, and in susceptibility to in vitro attack by enzymes. Average particle diameter of four starch granules was negatively correlated with swelling power at 92.5 °C (r = −0.956, p < 0.05), and positively correlated with conclusion temperature in the DSC (r = 0.988, p < 0.05). Correlation between swelling power at 92.5 °C and conclusion temperature was also significant (r = −0.973, p < 0.05). This study provides sufficient information on properties of Chinese chestnut starches, which would be very helpful for their application in food and other industries.