Oyster mushroom (Pleurotus sajor-caju) can be processed into a shelf-stable plant-based seasoning powder while preserving flavor and nutritional compounds. Researchers found the most stable formulation used 10% maltodextrin and 1% gum arabic as drying carriers, producing a powder with low water activity (0.42) and moisture around 4–5%, conditions that help prevent microbial growth. The final seasoning retained key flavor compounds including 10.86 mg glutamic acid per 100 g along with measurable phenolics and flavonoids, showing mushrooms can function as a natural umami seasoning ingredient.