## 2 Materials and Methods
### Sensory Evaluation  
This survey was conducted in January 2018 and featured 86 healthy participants (67% women and 33% men, aged 18 to 40) from the Beijing Forestry University. The inclusion criteria were regular vinegar consumption, as well as sufficient interest and time to participate in the study. The respondents were asked to complete an online questionnaire before evaluating the samples, which consisted of 32 questions divided into four sections: (1) Basic Information of Consumers. This section included eight questions regarding name, gender, age, permanent residence in the last ten years, occupation, vinegar consumption frequency, experimental participation time, and contact information. (2) Preference for Vinegar. This section investigated the attitude of the respondents towards vinegar via ten statement questions, which were scored on a 7-point scale. The 1-7 scale represented the responses, \"strongly disagree\", \"disagree\", \"disagree slightly\", \"indifferent\", \"agree slightly\", \"agree\", and \"strongly agree\", respectively. The respondents were required to rate each statement question according to their actual situations. (3) General Health Interest. This section also investigated the attitude of the respondents towards vinegar using ten statement questions scored on a 7-point scale. The 1-7 scale represented the responses, \"strongly disagree\", \"disagree\", \"disagree slightly\", \"ingree\", and \"strongly agree\", respectively. The respondents were required to rate each statement question according to their actual situations. (4) Consumer Purchasing Behavior and Preferences. This section consisted of four questions regarding understanding the vinegar aroma, the factors valued by the participants when choosing vinegar, the difference in vinegar quality, and the type of vinegar generally purchased.  
This study evaluated six vinegar samples during a single experiment lasting for approximately 15-30 min. Here, 5 mL of each sample was placed in separate 30 mL brown PET plastic vials at room temperature and labeled with random three-digit numbers. The samples were placed on separate tables under artificial white light. The participants were required to smell each sample, with a 3 min resting period between samples to remove the residual odor of the previous sample. After entering the evaluation room, the respondents smelled six different vinegar samples successively to determine the difference between the vinegar aromas. Then, the respondents scored each sample within 30 according to their personal liking and provided comments for 2 min. The vinegar samples were subjected to a sequential blind test, while the smelling order was rotated for each respondent to avoid the bias caused by the smelling sequence. This test was repeated six times. A 7-point scale was used, with points 1-7 representing \"particularly dislike\", \"dislike\", \"dislike slightly\", \"just so, so\", \"like slightly, \"like\", and \"particularly like\", respectively. After the evaluation, the respondents were asked to reply to an additional two questions. (1) \"Why do you like this sample?\" \(\rightarrow\) \"Is there any other reason?\" (2) \"Why don't you like this sample?\" \(\rightarrow\) \"Is there any other reason?\" The tests were conducted in controlled conditions in accordance with the ISO8589:2007 standard. All respondents have consented to participation in the study. In the consumer stage, there were 86 participants, while only 76 participants completed the sensory evaluation. The data in this study were the data of the 76 participants