Nutritional and Bioactive Compounds: Evaluation of Pleurotus pulmonarius (Fries) Quel. Fruit Bodies Grown on Different Wood Logs in Abia State, Nigeria

Abstract

IntroductionMushrooms are unique biota which assemble their food by degrading enzymes and decompose the complex food materials present in the biomass where they grow [1]. Oyster mushrooms can be grown on various substrates due to its strong enzymatic features. Different substrates are used in each region depending on their availability [2]. Wheat straw, sawdust and other agricultural by-products resulting after processing of waste paper, Hazelnut and Tilia have been used in Oyster mushroom cultivation [3]; maize, corn, rice, elephant grass [4], sugarcane [5], coffee [6] have been examined as alternative substrates for its cultivation. These substrate materials are usually by products from industries, households, agriculture etc., and are usually considered as wastes [7]. However, these wastes are actually resources in the wrong place at a particular time and mushroom cultivation can harness them for its own benefit [8].Kadiri and Aizai [9] showed that Lentinus subnudus could be cultivated on wood logs of tropical trees. According to Hyunjong and Seung [10], hard woods such as poplar, willow, beech, elm and alder are the most commonly used tree species in oyster mushroom cultivation. He noted that unlike shiitake, Oyster mushrooms do not grow well on Oak tree logs. Hyunjong and Seung [10] reported that since mushroom feed primarily on sapwood, any tree trunk selected for inoculation must have a larger sap wood area. The lighter or outermost wood of a log is the sapwood and the darker or inner wood is the heartwood.The desirability of a food product does not necessarily bear any correlation to its nutritional values instead, its appearance, taste and aroma, sometimes can stimulate one's appetite [8]. Mushroom has been used as a food and medicine by different civilizations since immemorial AbstractThis study was conducted to determine the nutritional and bioactive compounds composition of Pleurotus pulmonarius fruit bodies cultivated on tree logs of Dacryodes edulis, Mangifera indica and Treculia africana. Pure mycelium culture of P. pulmonarius was aseptically bulked in sorghum grains. Logs were cut into average length of 18 cm with inoculation holes of 3 cm × 15 mm diameter; using high speed drill (HSD) of 5 drill bit and allowed to decompose for 8 months. During mushroom cultivation, logs were soaked in tap water for 24 hrs and pasteurized at 80°C in an improvised metallic drum (IMD) for 1 hour; using cooking gas as heat source and allowed to cool overnight. 10 g of grain based spawn was inserted into 2/3 of each hole by way of inoculation and sealed with sterile polybag for mycelium incubation. Polybags were cut open after spawn run following primordial initiation. Fruit bodies were harvested at maturity, sundried ground and packed in airtight container prior to further analysis. Data was analysed using Analysis of Variance (ANOVA) and mean separation by Duncan Multiple Range Test (DMRT) while levels of significance were determined at 5%. Results indicate that P. pulmonarius fruit bodies harvested from variou...