Seeds of Coix lacryma-jobi as a functional additive in steamed buns: Effects on bun quality and starch digestibility

Seeds of Coix lacryma-jobi (SCL) are widely used as food and medicine in many Asian countries. This study examines the effects of SCL incorporation on steamed bun quality and starch digestibility. SDS-PAGE analysis suggests SCL disrupt gluten formation, reducing the buns’ specific volume and gas-holding capacity. Furthermore, an increase in the SCL content of the buns results in a decrease in L∗ values and an increase in a∗ values. Despite these changes, the bun maintains acceptable general acceptability, scoring 4.8 ± 2.1 out of 10 for the bun containing 600 g/kg of SCL compared to 6.9 ± 1.7 for the one made entirely of flour. Moreover, increasing the SCL content of the buns from 200 g/kg to 800 g/kg reduces the hydrolysis index (HI) from 101.9 ± 3.9 to 74.6 ± 6.5 and the estimated glycaemic index (eGI) from 95.7 ± 2.1 to 80.7 ± 3.5. This decrease in HI and eGI is attributed, in part, to the increased protein and lipid content of the buns. These findings suggest that SCL incorporation warrants further investigation as a potential strategy for developing low-glycaemic-index, carbohydrate-rich products for consumers concerned about blood sugar levels. • Starch digestibility in steamed buns is lower after SCL incorporation. • SCL hinders gluten formation, reducing bun volume and gas retention. • SCL incorporation reduces the hydrolysis index and glycaemic index of the bun. • The steamed bun retains general acceptability after SCL incorporation. • The SCL-incorporated bun causes less postprandial blood glucose fluctuations.