Effect of thermal processing on the physicochemical properties of chestnut starch and textural profile of chestnut kernel

• The physicochemical properties of chestnut starch after cooking were evaluated.
• The microstructure of starch was destroyed during thermal processing.
• The starch in cooked chestnut still exhibited C-type XRD with weaker intensity.
• Roasted chestnut exhibited better texture characterizations than boiled chestnut.
• Roasting is an alternative industrial thermal processing method for chestnut kernel.

The present study focused on the effect of thermal processing on the physicochemical properties of chestnut starch and textural profile of chestnut kernel. After thermal processing, the total starch content in both boiled and roasted chestnuts decreased significantly (P < 0.05), while the amylose content of boiled chestnut increased and that of roasted chestnut remained stable. The granular microstructure of the starch in cooked chestnut was gradually destroyed during the thermal processing. The starch in cooked chestnut still exhibited C-type X-ray diffraction patterns, but the intensity of diffraction peaks and the crystallinity were obviously declined compared with those of fresh chestnut. Textural profile analysis of chestnut starch gel and chestnut kernel showed that the main textural characterizations of roasted chestnut were higher than those of boiled chestnuts. These results are helpful for better understanding the texture change in fresh, boiled and roasted chestnuts, which indicated that roasting is an alternative industrial thermal processing method for chestnut kernel.