Effect of different processing steps on the volatile flavor profiles of tea-fragrant chicken determined by HS-GC-IMS and chemometrics

Tea-fragrant chicken (TFC) is a renowned and traditional product of Chinese cuisine. This study aimed to assess the effect of different processing stages on the quality of TFC for the first time. The influence of tenderization with fig protease (TC), marination with tea curing solution (MC), and braising (BC) for various times, including 20 min (BC-20), 40 min (BC-40), and 60 min (BC-60) on the flavor enhancement of TFC, in comparison to raw chicken (RC), was evaluated using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The findings reveal the presence of 50 volatile flavor compounds throughout the six processing stages. These compounds include aldehydes, ketones, alcohols, esters, furans, hydrocarbons, ethers, phenols, and monoterpenes, with the highest intensities for aldehydes, alcohols, and ketones. The findings indicated a small difference in the concentration of volatiles between RC and TC samples. The marination treatment significantly increased the amount of alcohols, ketones, esters, and monoterpenoids, resulting from the diffusion of flavors from the tea and spices. Extending the braising time can significantly enhance the development of flavor components, resulting in the BC-60 having an extensive amount of flavors. The volatiles contributed to the aroma profile of TFC, including a mint note from 1,8-cineole (M), a sweet scent from ethanol and 2-butanone, fatty and grassy notes from hexanal, an almond aroma from benzaldehyde, and pentanal (D), a cocoa note from 2-methylbutanal (D), an aldehydic scent from 3-methylbutanal (D), a pungent odor from acetone, a fruity note from 2-pentanone (D), a citrus scent from 6-methyl-5-hepten-2-one, a spicy note from 4-vinyl-2-methoxyphenol (M), and turpentine-like odor from alpha-pinene. These findings provide valuable perspectives for improving the quality production of TFC. Moreover, these results can provide a foundation for the continued advancement of pre-packaged TFC.