Effects of culture periods on fruiting body formation and bioactive compounds production of Cordyceps militaris

Cordyceps militaris was traditionally used as a tonic and traditional folk medicine, especially in East Asia. Adenosine and cordycepin (3'-deoxyadenosine) were an important active ingredient of C. militaris. The objective of this study was to investigate the effect of culture periods on physico-chemical characteristics of fruiting body (fresh weight, length, firmness, total soluble solids concentration (TSS), and color) and determine the bioactive compounds (adenosine and cordycepin) production of C. militaris. The experimental design was a Completely Randomized Design. C. militaris was cultured on the rice culture medium (PDB, white rice, silkworm pupa and egg) for 1, 2, 3, 4, 5, 6, 7, 8 and 9 weeks. Results showed that the fresh weight, length, TSS of fruiting body were significantly increased as the culture period increased and was stable from the 7^th till the 9^th week. The lightness (L*) decreased as the culture period increased while the redness (a*) and yellowness (b*) were increased and then slightly decreased from the 2^nd to the 9^th week. Adenosine and cordycepin contents were detected after the 1^st week of culture periods. They significantly increased from the 1^st till the 7^th week of the culture periods. After 7 weeks, these bioactive compounds significantly decreased. This experiment revealed that the optimal harvesting time for C. militaris was the 7^th week. At this culture period time, the yield of fresh weight of fruiting bodies was 41.77 g bottle^‑1 and the amounts of adenosine and cordycepin were 2.7 and 6.21 mg g^‑1, respectively.