蛹虫草液体发酵培育子实体及其营养成分、色素稳定性分析

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

摘要:

【背景】 蛹虫草(Cordyceps militaris)是一种有很高营养和药用价值的药用真菌，目前其子实体主要通过固态发酵的方法进行生产。【目的】 探索液体发酵培育蛹虫草子实体，并分析其营养成分及色素稳定性，为生产提供一种新选择。【方法】 蛹虫草菌株在液体培养基摇床培养使菌丝大量生长，光照条件下静置培养诱导子实体形成和生长，化学分析测定子实体的营养成分，吸光度变化分析蛹虫草色素的稳定性。【结果】 蛹虫草液体发酵原基形成期为10.8 d，从原基形成到子实体成熟时间为37.3 d，生产周期为48.1 d，较固态发酵(57.8 d)缩短9.7 d。鲜重产量为每瓶6.72 g，低于固态发酵(8.29 g)。子实体粗蛋白、粗脂肪和灰分含量分别为44.5%、2.6%和8.8%，固态发酵为28.5%、1.4%和4.6%，分别提高56.14%、85.71%和91.30%；粗纤维含量为12.9%，低于固态发酵(15.4%)。子实体色素含量为740.21 µg/g，低于固态发酵子实体(867.45µg/g)。温度和pH对液体发酵和固态发酵培育子实体色素的影响有一定差异，而时间、氧化剂(H₂O₂)、还原剂(维生素C)及NaCl对液体发酵和固态发酵培育子实体色素的影响无差异。【结论】 利用液体发酵培育蛹虫草子实体，不但缩短生产周期，还可提高营养价值，具有较好的应用潜力。

关键词:蛹虫草;液体发酵;固态发酵;农艺性状;天然色素

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.

Key words:Cordyceps militaris;liquid fermentation;solid-state fermentation;agronomic trait;natural pigment