Impact of Substrate Disinfection on Yield and Efficiency of Drying Methods for Quality Preservation of Elm Oyster Mushroom Hypsizygus ulmarius (Agaricomycetes) and Its Medicinal Value.

Abstract

This paper evaluated the effect of different substrate disinfection methods viz. hot water treatment, autoclaving and steam pasteurization at 100°C, 121°C, and 65°C, respectively, on yield of Hypsizygus ulmarius and effects of sun drying, oven drying and cabinet drying techniques at 25 ± 2°C, 40 ± 2°C, and 50 ± 2°C, respectively, on nutritional qualities of H. ulmarius. Hot water treated substrate gave higher yield (215.36 ± 1.49 g) and biological efficiency (71.78%) compared with autoclaved (194.45 ± 3.36 g and 64.81%) and steam pasteurized substrate (194.45 ± 3.36 g and 65.28%). The different drying methods used for drying the fruit bodies significantly influenced the nutrient profile of H. ulmarius. Highest moisture (6.95%), fiber (16.94%) and protein content (22.49%) was retained in sun dried fruit bodies whereas ash content (5.52%) was highest for oven dried fruit bodies. Cabinet dried fruit bodies showed significantly higher percentage of fats (1.82%) and carbohydrates (53.58%). In the DPPH assay the cabinet dried fruit bodies showed the highest antioxidant activity followed by sun dried and oven dried fruit bodies with respective IC50 values as 104.21 ± 0.14, 117.17 ± 0.07 and 163.57 ± 0.02. The drying methods proved to be effective in controlling the bacterial growth for a period of two months after which significant bacterial growth was noted.