Effect of Cooking Method and Enzymatic Treatment on the in vitro Digestibility of Cooked and Instant Chestnut Flour

Microwave treatment, roasting, boiling, and enzymatic treatment were used to prepare cooked and instant chestnut flour, and the in vitro digestibility were compared. Cooking gelatinized the starch and destroyed the granular and crystal structure, increasing starch digestibility. After enzymatic hydrolysis, starches were degraded by 20 similar to 24%, and the reducing sugar content of the instant flours increased by 79 similar to 94%. Starch digestibility was reduced after enzymatic hydrolysis, however, the estimated glycemic index (GI) increased to 65.1 similar to 77.7 due to the combined effect of increased reducing sugar and decreased starch hydrolysis in the instant flours. The chestnuts treated by 'boiling+enzymes' are still a medium GI food. These findings give guidance for the development of low GI cooked and instant chestnut flour.

Automated summary

Microwave treatment, roasting, boiling, and enzymatic treatment were used to prepare cooked and instant chestnut flour, and their in vitro digestibility and glycemic index were compared. The results showed that cooking increased starch digestibility, while enzymatic hydrolysis decreased it. The combined effect of increased reducing sugar and decreased starch hydrolysis in the instant flours led to higher glycemic index values.