Effect of Different Baking Degrees of Oak on Lychee Brandy Volatility Flavor Based on Electronic Nose and GC-MS

In order to study the influence of oak chips with different toasty degrees on the aging flavor of lychee brandy, oak chips with different toasty degrees were added to lychee brandy for aging. The quality and volatile flavor components of four types of lychee brandy (lychee brandy, lightly toasted, medium toasted, and heavily toasted) were evaluated and analyzed using sensory evaluation, electronic nose, and gas chromatography-mass spectrometry. The results showed that a total of 21 volatile aroma compounds were identified in four types of lychee brandy, among which esters and alcohols present in the four wines, with high odor activity value and significant contribution to the flavor of the brandy. Their composition and content constituted the main volatile aroma characteristics of lychee brandy. Additionally, the lychee brandy exhibited distinctive olefins and aromatic hydrocarbons, while lychee brandy aged with different levels of toasted oaks contained unique aldehydes and ketones. The lychee brandy contained the highest number and relatively higher content of flavor compounds. In contrast, light and medium roasted oak-aged lychee brandy contained fewer types of flavor compounds, predominantly esters, alcohols and aldehydes and ketones, while heavily roasted oak-aged lychee brandy exhibited the presence of some olefins and aromatic hydrocarbons. In terms of sensory evaluation, the heavily toasted oak-aged lychee brandy achieved the highest score and possessed a superior flavor. Furthermore, electronic nose detection clearly distinguished lychee brandy aged with oak chips of different toasting degrees. Overall, the addition of heavily roasted oak chips enhanced the aging quality of lychee brandy.