Effect of different drying treatments on the proximate compositions of maitake (Grifola frondosa) mycelium

Grifola frondosa or commonly known as maitake is an edible medicinal fungus that get great attentions from customers. However, the conventional maitake cultivation
requires longer period compared to submerged method. Mushroom complete medium (MCM) was used in this study containing glucose (20g/L), yeast extract (2g/L), peptone
(2g/L), magnesium sulfate heptahydrate (0.59/L), dipotassium hydrogen phosphate (1g/L) and potassium dihydrogen phosphate (O.46g/L). The maitake mycelium was
harvested after submerged fermentation (14 days) using rotary shaker with 10% (v/v) pure maitake inocuium. The biomass were then treated with vacuum (70°C in 1000
mbar for 24 hours) and oven drying (105°C for 24 hours) followed by determination on their proximate compositions. The submerged fermentation used MCM able to yield the maitake mycelia at 1.32 ± 0.09g/L. In this study oven dried mycelium showed higher proximate composition than vacuum oven which possessed moisture (92.13 1 0.31%), protein (34.76 ± 0.11%), crude fat (3.56 ± 1.23%), crude fiber (2.01 ± 0.28%) and ash (9.84 ± 0.24%). The proximate composition observed in wet mycelium sample, for instance, protein, crude fat, crude fiber, and ash were 3.09 ± 0.06, 0.65 ± 0.21, 0.31 ±
0.02%, and 0.86 ± 0.00% respectively. However the total carbohydrate determined from wet sample was 95.40 ± 0.28%, was highest compared to vacuum oven (51.84 ± 0.87%) and oven dried (44.18 ± 0.20%) mycelia. In conclusion, submerged fermentation by using MCM has potential to produce maitake myceiium in short period.
The oven drying treatment was recommended to improve the proximate compositions of maitake mycelium compared with vacuum oven. Future study will focus more on the effect of oven drying towards the amino acid and soluble protein level of maitake mycelia.