Utilisation of dried shiitake, black ear and silver ear mushrooms into sorghum biscuits manipulates the predictive glycaemic response in relation to variations in biscuit physical characteristics

The nutritional quality of gluten-free products is important to the health of individuals with coeliac disease. Mushrooms are good sources of vitamins, dietary fibres and proteins, and are a low-calorie option that can be used in gluten-free diets to improve their nutritional value. The effects of incorporating dried mushrooms on the hydration and pasting properties of sorghum flour, as well as the physicochemical characteristics and in vitro glycaemic response of sorghum biscuits were studied. Sorghum flour enriched with mushroom powders exhibited higher water absorption capacity and swelling power compared with the control (P < 0.05). The addition of shiitake (Lentinula edodes) mushroom significantly decreased the pasting viscosities, while the addition of black ear (Auricularia auricula) and silver ear (Tremella fuciformis) mushroom increased viscosity values (P < 0.05). Biscuit diameter, thickness and weight loss were reduced with increasing mushroom powder addition, and the colour parameters of biscuits were affected significantly. Enrichment with shiitake and black ear mushroom increased the hardness of biscuits (P < 0.05). Inclusion of mushroom powders significantly reduced the predicted glycaemic response of sorghum biscuits (P < 0.05). Correlation analysis was conducted to illustrate that hydration dynamics (such as water absorption capacity and swelling power) were negatively correlated with glycaemic response (P < 0.001).