Standardization of biomedicinal enrichment in edible oyster mushroom, Pleurotus sp.

Abstract

The present study entitled “Standardization of biomedicinal enrichment in edible oyster mushroom, Pleurotus sp.” was conducted at Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram during 2019-2021, to standardize the substrate(s) amended with medicinal plants for the cultivation of edible oyster mushroom, P. florida and analysis of the uptake of bioactive compounds of pharmaceutical importance by P. florida. In vitro evaluation of the effect of medicinal amendments (adathoda, neem and ocimum) on mycelial growth of P. florida revealed that there was a significant variation with respect to growth pattern and mycelial density. The radial growth of mycelium in PDA media amended with adathoda 1000 ppm, neem 1000 ppm and ocimum 250 ppm concentration was on par with control. The addition of medicinal amendments had no inhibitory effect on mycelial growth of P. florida. The basidial size from the sporocarp of amended mushrooms varied widely with maximum size in amended ones when compared to control. The mycelial width did not vary significantly among all the treatments. In vivo evaluation of medicinal amendments by soaking and spraying method revealed that addition of amendments reduced the days for spawn run, pin head initiation and first harvest. Desirable sporophore characters for enhanced yield was also observed when compared to control. Maximum yield was recorded in soaked beds when compared to sprayed beds and control. Ocimum was found to be the best amendment with an average yield of 448.75 g from soaked beds (T5) and 434.5 g from sprayed beds (T6). Sporophore characters of P. florida showed significant variation among the different treatments. There was enhanced shelf life of amended mushrooms under both room temperature and refrigerated condition. Neem sprayed (T4) and adathoda soaked (T1) samples had a better shelf life of 5 and 4 days respectively under refrigerated conditions as well as in room temperature (3 days respectively). Sensory evaluation scores of P. florida from different treatments were obtained for parameters viz., appearance, colour, flavor, texture and taste. The maximum scores for appearance was obtained by ocimum amendment. Mushroom from neem sprayed treatment was adjudged the tastiest. The major pests observed in the beds were sciarids, Megaselia sp. and staphylinid beetle. Neem amended beds showed reduced pest incidence (10-15%) when compared to control (20%). Trichoderma was the common contaminant observed along with Coprinus and bacteria. Least disease incidence of 10 per cent was observed in neem sprayed, adathoda sprayed and ocimum soaked treatments. Least disease incidence was recorded in sprayed beds than soaked beds. GC-MS studies of mushroom and substrate samples revealed the identification of many important compounds of pharmaceutical importance. The different classes of compounds observed were aldehydes, ketones, organic acids, esters, ethers, furan derivatives, sterol and nitrogen derivatives. Exclusive compounds could be identified viz., pidolic acid, ethyl iso-allocholate and erucic acid from mushroom samples whereas quinolone, myristyl monoethoxylate, epoxylanostan, adenosine and digitoxin from substrate samples. Biochemical analysis of beta-carotene, flavonoids, terpenoids and polyphenols from the mycelium and sporocarps revealed that there was enhanced concentration of above said bioactive compounds in sporocarp when compared to mycelia. Adathoda amended mycelia recorded maximum beta-carotene, flavonoid, terpenoid and polyphenol content. In the case of sporocarps, maximum beta-carotene content was recorded in adathoda soaked treatment. Neem amended sporocarp recorded maximum flavonoid content. Ocimum amended sporocarp recorded maximum terpenoid and polyphenol content. In the current study entitled ‘Standardization of biomedicinal enrichment in edible oyster mushroom, Pleurotus sp.’ it was observed that there was pronounced enhancement of yield attributes in amended mushrooms. Reduced pest and disease incidence was also observed. There was improvement in shelf life and organoleptic characters in amended mushrooms. New compounds of pharmaceutical importance could be identified by GC-MS analysis. The bioactive compounds viz., beta-carotene, flavonoid, terpenoids and polyphenols were also found to be enhanced when compared to control.