Cordyceps militaris fruiting bodies: cultivation by liquid fermentation, nutrient composition, and pigment stabilit

Abstract:

[Background] Cordyceps militaris is a medicinal fungus with high nutritional and medicinal values, and its fruiting bodies are mainly produced by solid-state fermentation. [Objective] To provide a new option for the production of C. militaris fruiting bodies by liquid fermentation and determine the nutrient composition and pigment stability of the fruiting bodies produced. [Methods] Shaking culture was employed for the extensive mycelial growth of C. militaris in a liquid medium, and then static culture with illumination was carried out for inducing fruiting body formation and growth. The nutrient composition of the fruiting bodies was determined by chemical assays, and the absorbance changes of pigments extracted from the fruiting bodies were determined to evaluate the pigment stability. [Results] The cultivation of C. militaris by liquid fermentation took 10.8 d for primordium emergence and 37.3 d for fruiting body growth (from primordium emergence to fruiting body harvest). The production cycle in this cultivation mode was 48.1 d, 9.7 d less than that (57.8 d) of solid-state fermentation (control). The fresh fruit body yield was 6.72 g per bottle, lower than that (8.29 g per bottle) of the control. The content of crude protein, crude fat, and ash was 44.5%, 2.6%, and 8.8%, respectively, in the fruiting bodies cultivated from liquid fermentation and 28.5%, 1.4%, and 4.6%, respectively, in the control, with increases of 56.14%, 85.71%, and 91.30%, respectively. The crude fiber and pigment content in the fruiting bodies cultivated from liquid fermentation was 12.9% and 740.21 µg/g, respectively, lower than those (15.4% and 867.45 µg/g, respectively) of the control. Temperature and pH exerted different effects on the pigment stability of the fruiting bodies cultivated from liquid and solid-state fermentations, while the time, oxidant (H₂O₂), reductant (vitamin C), and NaCl had similar effects on the samples cultivated in the two modes. [Conclusion] Liquid fermentation for the production of C. militaris fruiting bodies can not only shorten the production cycle but also improve the nutritional value, demonstrating great potential for industrial applications.