Influence of Drying Temperatures on Colour Variation, Phenolic Compounds and Multi-Elemental Composition of Some Culinary- Medicinal Mushrooms

Although mushrooms are widely used for nutraceutical purposes, however, post-harvest storage is extremely crucial to avoid degradation and reduction in quality of fresh mushroom. Drying treatments are commonly applied in mushroom industry to extend the shelf-life. Drying may cause instability to food quality and antioxidant parameters due to unsuitable drying temperatures. Therefore, in this research, common set of temperatures usually used by mushroom growers was applied (50°C, 60°C, 70°C) to Ganoderma lucidum, Lignosus rhinocerus, Auricularia auricula-judae, and Schizophyllum commune to analyse the color changes, the concentration of elements and phenolic compounds. Mushrooms were chosen based on commonly cultivated species among growers. L. rhinocerus dried at 70°C indicated significantly lower L* value (78.90) compared to control (89.94). The elements retention in each sample differed depending on the species. The amount of calcium was significantly higher in L. rhinocerus (11893 mg/kg) and A. auricula-judae (10941.81 mg/kg) when dried at 60°C. Mushroom dried at 70°C resulted in significantly higher magnesium for Sch. commune (13054.38 mg/kg) and A. auricula-judae (8056.92 mg/kg). Higher levels of iron and manganese were observed in Sch. commune dried at 70°C with a value of 216.54 mg/kg and 10.02 mg/kg, respectively. Gallic acid had significantly higher retention at 50°C for A. auricula-judae and G. lucidum. Meanwhile, L. rhinocerus and Sch. commune indicated significantly higher gallic acid at 60°C. It is evident from the results that temperature does affect the food quality and elemental parameters during the drying process for each mushroom.