Phenotypic, nutritional, and bioactive characteristics of Pluerotus pulmonarius grown on three different substrates

Abstract

This paper investigated the impact of substrates on the physical and biochemical properties of Pluerotus pulmonarius. The mushroom was grown on three different substrates: sawdust (sds), palm bunch (pbs) and corn cob (ccs), in the cropping house for 28 days for fruiting bodies to emerge. The phenotypic properties of the mushrooms grown from the three different substrates designated as sdm, pbm, ccm, were measured. Proximate composition, phytoconstituents and antioxidant activities were determined using standard methods while the amino acid profile and mineral analysis were determined using HPLC and ICP-AES, respectively. From our results, the electrical conductivity of the substrates was high. The mushroom grown on pbs supported the growth and yield of the mushroom most while ccm produced mushroom with the least phenotypic attributes. The mushroom grown on all the substrates had high crude protein content and low-fat content, however pbm had the highest crude protein content of 25.19 %. Amino acid profile showed all the essential amino acids in all the mushrooms. Interestingly, sdm had the highest (P<0.05) amino acid concentration compared to pbm while ccm had the least. Mineral analysis showed the presence of essential trace minerals including Fe, Zn and Cu which were either absorbed or bioaccumulated by the mushrooms especially those grown on sds and pbs. The substrates pbs (Fe: 537.12 ppm), and ccs (Cu: 11.37 ppm, Zn: 59.33 ppm) had the highest (P<0.05) concentration of the minerals. The phytochemical composition of the mushrooms was relatively low: phenolics (1.27 mg/g), flavonoids (0.87 mg/g), tannins (1.08 mg/g), saponins (1.49 mg/g), alkaloid (0.43 mg/g). The mushrooms showed antioxidant activity and the highest activity was seen with ABTS⁎ free radical scavenging using pbm (82.21 mmolTEAC/g). The mushrooms inhibited cholinesterase and lipase activities indicating possible use in therapeutics. Our data indicates that pbs provided the most support and nourishment that significantly impacted the physical and, in some degree, the biochemical characteristics of the mushroom followed by sds. Our data together suggests that pbs maybe the most viable in mushroom growth among all tested substrates.