Variation of aromatic components in different distillation fractions of distilled Huaniu apple spirit

In this study, the volatile aroma components of distilled Huaniu apple spirits at different distillation stages (distillation fraction Ⅰ with alcohol content 90%vol, distillation fraction Ⅱ with alcohol content 75%vol, distillation fraction Ⅲ with alcohol content 53%vol, distillation fraction Ⅳ with alcohol content 30%vol) were analyzed using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME- GC-MS). The results showed that a total of 108 aroma compounds in distilled Huaniu apple spirits were identified, including 61 esters, 33 alcohols, 5 acids, and 9 aldehydes and ketones. In the distillation process, the content of ester substances gradually decreased, the content of acid substances continuously increased, while the content of alcohols, aldehydes and ketones increased first and then decreased. Among them, the content of esters was the highest in distillation fraction Ⅰ, reaching 9 971.19 mg/L, the content of alcohols was the highest in distillation fraction II, reaching 2 328.92 mg/L, the content of acids was the highest in distillation fraction Ⅳ, reaching 1 363.42 mg/L, whereas the content of aldehydes and ketones was the highest in distillation fraction II, reaching 22.47 mg/L. Different distillation fractions of distilled Huaniu apple spirit were classified into three categories by hierarchical cluster analysis (HCA), distillation fraction Ⅰ with high types and contents of esters was a class, distillation fraction Ⅱ with high types and contents of alcohols was a class, distillation fraction Ⅲ and Ⅳ with high types and contents of acids, aldehydes and ketones were classified as a class. These study results provided a key basis for the in-depth understanding of the aroma formation mechanism of distilled Huaniu apple spirit, and provided theoretical support for optimizing production technology and improving product quality.