Effect of drying methods on the phytochemical composition and bioactive compounds of two oyster mushroom species using GC-MS

Pleurotus ostreatus is a treasured mushroom known for its abundance of bioactive compounds with high nutritional, medicinal, and therapeutic properties. The study evaluated the effects of two drying methods; oven drying and sun drying, on the phytochemical composition of Pleurotus ostreatus (grey and white varieties). Samples were collected from an indoor mushroom farm, cleaned with water, and subjected to pre-treatment and drying. One portion was sun-dried at room temperature, another oven-dried at 120 °C for 1 hour, while fresh mushrooms served as the control. Soxhlet extraction was used for sample preparation, and Gas Chromatography-Mass Spectrometry (GC-MS) was utilized for the detection of compounds. Bioactive compounds were identified using Retention Time (RT) compared with standards in the National Institute of Standards and Technology (NIST) library. Results showed that sun-dried grey mushrooms had 26 compounds, oven-dried had 22, and fresh samples had 24, including hydrocarbons, siloxanes, and aromatic acids. White oyster mushrooms contained 19 compounds in sun-dried samples and 14 in oven-dried samples, with linoleic acid derivatives and phenolic compounds present in high concentrations. Key bioactive compounds identified include 9, 12-Octadecadienoic acid (Z, Z)-methyl ester, Heptasiloxane, and Bicyclo [3.1.0] hex-3-en-2-one derivatives, all of which are known for their antioxidant, antimicrobial, and anti-inflammatory properties. The presence of sulfur-containing and siloxane-based compounds suggests possible uses in the food, agriculture, and pharmaceutical sectors. Both drying procedures significantly affected the mushrooms’ chemical profiles; however, sun-dried samples retained more phytochemicals across both species, indicating that sun drying can preserve important bioactive constituents and improve compound availability.