Objective To identify flavor compounds in Douzhir and Ma Tofu and analyze their characteristic components based on purge and trap-gas chromatography/mass spectrometry (PT-GC/MS) combined with the national institute of standards and technology (NIST) database. Methods Weigh 2.0 g of sample into a 40 mL brown spiral sample bottle, add 10 mL of experimental water and a tetrafluoroethylene magnetic stirrer, heat the sample at 40 ℃, and analyze it by PT-GC/MS. Results A total of 260 kinds of flavor compounds were identified across 34 batches, including sulfur-containing compounds, alcohols, aldehydes, ketones, esters, etc. Raw and cooked Douzhir exhibited significantly higher relative abundances of sulfur-containing compounds compared to Ma Tofu, which showed greater diversity but lower similarity in flavor profiles. These identification data could to some extent reflect sensory evaluation results, but there was a possibility that some flavor compounds might be more prominent or interfered with by other odors. In addition, this study used principal component analysis (PCA) method to identify the overall distribution of samples and deviations from samples, and attempted to analyze the reasons for deviations. Further, using orthogonal partial least squares discriminant analysis (OPLS-DA), based on the screening conditions [P<0.05, variable importance in the projection (VIP)>1], 31 kinds of characteristic flavor compounds of raw and cooked Douzhir were selected, which could be used for the differentiation and identification of raw and cooked Douzhir. Conclusion The study confirms that PT-GC/MS combined with multivariate statistical method can effectively analyze the flavor compounds of Douzhir and Ma Tofu, screen the characteristic compounds, and provide a basis for the subsequent optimization and improvement of product flavor.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |