Advances in Research

Oyster mushroom (Pleurotus ostreatus) is a perishable food ingredient that can be incorporated into processed products following dehydration. This study characterised fresh oyster mushrooms, examined their tray-drying behaviour, and developed and evaluated nutritional bars containing oyster mushroom powder and spirulina (Arthrospira platensis). Cap diameter, stipe length, weight, pH, total soluble solids and moisture content were measured in three fresh mushroom samples. Mushroom slices were tray-dried at 60 °C for 240 min. Three bar formulations contained 15, 18 or 20 g of mushroom powder and 20, 17 or 15 g of foxtail millet flour, respectively, while spirulina and the remaining ingredients were held constant. Colour, flavour, texture, taste and overall acceptability were assessed using a nine-point hedonic scale. The highest-rated treatment underwent proximate analysis and cost estimation. Fresh mushrooms had mean values of 76.84 mm for cap diameter, 34.85 mm for stipe length, 43.38 g for weight, 6.38 for pH, 2.17 °Brix for total soluble solids and 88.95% for moisture. During drying, moisture content decreased from 900.00% to 0.22% on a dry basis, with a declining drying rate. Treatment II had the highest overall acceptability score (9.0), compared with Treatments I (7.3) and III (8.2). Per 100 g, Treatment II contained 15.1 g protein, 6.4 g dietary fibre, 18.1 g fat and 17.1 g moisture. Its estimated production cost was ₹144.26 per batch. The results support further evaluation of this mushroom–spirulina bar formulation as a ready-to-eat product.