为获得活性物质含量较高且血糖指数（glycemic index，GI）较低的蛹虫草发酵菌质，以发酵菌质的预估血糖指数（expected glycemic index，eGI）、虫草素和喷司他丁含量为评价指标，通过单因素及正交试验对固体发酵培养基配方进行优化，并确定最佳培养时间。结果表明，蛹虫草固体发酵培养基的最优配方包括70%的主料和30%的辅料，其中主料由质量比为4:6的大米和燕麦混合组成，辅料为豆粕，二者混合后按料液比（m/V）1:0.9添加含10 g/L甘氨酸的液体完全培养基为营养液，25 ℃避光培养18 d。此条件下得到的发酵菌质eGI值为53.86，与初始配方相比，eGI值降低了9.39%，达到了低GI水平；虫草素含量为12204.55 mg/kg，喷司他丁含量为1021.48 mg/kg，分别比初始配方提高了348.13%和81.79%。优化所得低GI值、高虫草素和喷司他丁含量的蛹虫草发酵菌质为低GI功能食品的开发提供了原料。

In order to obtain the fermentation substance of Cordyceps militaris with high active components and low glycemic index (GI), the solid fermentation medium formula was optimized by single factor and orthogonal test, and the optimal culture time was determined using the expected glycemic index (eGI), cordycepin and pinastatin content of fermentation medium as evaluation indexes. The results showed that the optimal formulation of C. militaris solid fermentation medium consisted of 70% main materials and 30% auxiliary materials. The main materials were composed of rice and oat with mass ratio of 4:6, and the auxiliary materials were soybean meal. After mixing, a liquid complete medium containing 10 g/L glycine was added at the ratio of material to liquid (m:V) of 1:0.9, and the mycelia was cultured at 25 ℃ in dark for 18 days. Under these conditions, the eGI value of fermentation substance was 53.86, which decreased by 9.39% compared with the initial formula and reached the low GI level. The contents of cordycepin and pinastatin were 12204.55 mg/kg and 1021.48 mg/kg, respectively, which were increased by 348.13% and 81.79% compared with the initial formula. The optimized fermentation substance of C. militaris with low GI value, high cordycepin and pinastatin content provided raw materials for the development of functional food with low GI value.

国家自然科学基金青年基金项目（31601806）