New Method of Direct Sampling Gas Chromatography–Ion Mobility Spectrometry to Identify the Dynamic Retronasal Volatile Compounds in the Alcoholic Beverage and Their Release Behaviors: A Case Study on Huangjiu

Owing to extremely low concentrations and dynamic changes, it is difficult to detect and trace the retronasal volatile organic compounds (VOCs) generated during the consumption of alcoholic beverages. We developed a direct sampling gas chromatography–ion mobility spectrometry (GC-IMS) method to identify the dynamic VOCs after drinking Huangjiu-a fermented alcoholic beverages. The optimal procedure was obtained: take a sip of 10 mL Huangjiu, holding it in mouth for 10 s and then swallow, and the VOCs in one nasal expiration were collected with gas sampling bag and transferred directly to the injection port of GC-IMS. The repeatability was satisfactory (RSD < 5%). Twenty-two VOCs were detected in Huangjiu, with esters and alcohols being dominant, which were divided into five distinct release behavior groups. Their release was found significantly inhibited by saliva. Overall, this new method offers a technical approach to understanding and assessing the characteristics of retronasal aroma in alcoholic beverages.