Production of Antioxidant Bioactive Compounds during Mycelium Growth of Schizophyllum commune on Different Cereal Media

Abstract

Schizophyllum commune or split gill mushroom is a nutrient-rich natural food ingredient. Even during mycelium growth, S. commune could produce the bioactive compounds including phenolic and flavonoid compounds. The aim of this research was to characterize the production of bioactive compounds during mycelium growth period of S. commune cultured onto different eight edible cereal media (sorghum, corn, barley, wheat, oat, jasmine rice, Mun Poo rice and riceberry rice). The antioxidant activities and mycelial biomass were also observed during their growth. The results show that the highest mycelial growth rate was obtained onto barley and jasmine rice, while the lowest one was found in sorghum and corn. The concentration of phenolic compounds increased along with the mycelial growth. The fungal culture on wheat significantly exhibited the highest production of phenolic compounds which was 8.56 ± 1.09 mg GAE/g DW on day 8.The highest flavonoid production of 577.35 ± 29.93 μg CE/g DW, wasremarkably found onto barley from day 6. The degradation of certain flavonoidsin cereal materials by S. commune was also observed, particularly in riceberryrice. Antioxidant activity of cultured cereals was depended on the initial activitiesof materials and was mainly increased by S. commune metabolism. The DPPH•and ABTS•+ scavenging activities were sharply increased at day 4 which was earlystage of log phase of S. commune. At day 8, most of cereal media exhibited highDPPH• activity with a half maximal inhibitory concentration (IC50) range of 3.83-5.80 mg DW/mL, except jasmine rice. Only wheat and oat could significantly givethe highest ABTS•+ scavenging activity which was in an IC50 range of 2.38-3.27mg DW/mL. The highest FRAP activity with a median effective concentration (EC50)of 2.14 ± 0.23 mg DW/mL, was observed in barley which corresponded with itshighest flavonoid content. Antioxidant activities of S. commune culture onto cerealmedia were correspondent with their phenolic and flavonoid contents. Therefore,this study assured that several antioxidative substances were interestinglyproduced by using S. commune cultured onto the selected edible cereals, whichcould be possibly developed as a new supplement or active ingredient forpharmaceutical and food industries.