Abstract:To investigate the optimal scenting technology and the characteristic aroma components of sweet-scented osmanthus black tea, orthogonal experiments were carried out and the aroma components were analyzed by using headspace solid phase microextraction (HS-SPME) combined with Gas Chromatography-olfactometry-mass Spectrometry (GC-O-MS) technique. The results of the orthogonal test and sensory evaluation showed that the optimal scenting conditions were: The osmanthus-black tea ratio, 3:10, tanning three times with each lasting 4 hours. The GC-MS analysis revealed that the aroma components adsorbed into the sweet-scented osmanthus black tea were mainly four compounds cyclohexenol, nonyl aldehyde, γ-decalactone and 6,10,14-trimethyl-2-pentadecanone. The newly generated aroma components during the scenting process were mainly 1-octene-3-ol, 2-methyl-2-nonen-1-ol, 4-chloro-bicyclo [2.2.1] heptan-2-one, 3-methyl-2-furanmethylbutyrate, hexylpentanoate, trans-2-hexenyl pentanoate, and phenethyl butyrate. These results suggest that these 11 compounds were the main aroma components of osmanthus black tea. The GC-O analysis revealed that nonyl aldehyde exhibited oily and sweet orange odor, γ-decalactone possessed pleasant peach fragrance, 1-octene-3-ol had hay fragrance, trans-2-hexenyl pentanoate had creamy and fruity aroma, and phenethyl butyrate had honey sweet aroma. These five substances may be the characteristic aroma components responsible for the osmanthus fragrance of osmanthus black tea. In addition, the relative contents of alcohols significantly decreased while the contents of ketones and esters increased significantly during the scenting process.
