2.5. Preparation of H. erinaceus vinegar
After the completion of alcohol fermentation, alcohol content was adjusted to 5% and 2% acetic acid was added for the acetic fermentation (Kang, Jang, & Kim, 2006). A. aceti (10% v/v) was inoculated as the starter, and the broth was incubated at 30 °C in an incubator-shaker (250 rpm) (JEIO TECH, Daejeon, Korea).