This study evaluated the physicochemical properties and sensory acceptability of fortified mushroom sprinkle powder formulated with blends of Agaricus bisporus, ground chia powder, ultrasonic-treated flaxseed powder, and ground pumpkin seeds. Standard analytical methods and Pearson's correlations were employed to analyse blends with varying mushroom flour concentrations (10%, 15%, 20%, 25%, and 30%). Results indicated that increasing mushroom content enhanced protein, ash, fibre, zinc, and iron levels in both composite flours and fortified smoothies. Additionally, in vitro protein digestibility of the smoothies improved with higher mushroom incorporation. The inclusion of Pleurotus ostreatus flour increased pH and decreased total titratable acidity (TTA), while A. bisporus flour exhibited the reverse effect. Elevated mushroom content also led to reductions in fat, carbohydrates, energy, and viscosity in the fortified flours and smoothies. Positive linear effects were observed for functional properties such as foaming capacity, foam stability, fat absorption, water retention, water absorption, solubility index, and swelling capacity, whereas compact density, bulk density, and syneresis decreased linearly. Gelation capacity, emulsifying activity, and emulsion stability were unaffected by P. ostreatus but showed slight decreases with A. bisporus. This study underscores the potential of mushroom flours as a valuable food fortification ingredient, offering enhanced nutritional profiles and various healthpromoting benefits (R.M. Ishara Jackson1, Daniel N. Sila2, Glaston M. Kenji) (2018) [10].