Cov roj tseem ceeb, tseem hu ua volatile aromatic compounds, yog cov khoom siv tseem ceeb hauv kev lag luam tshuaj tsw qab. Nrog rau qhov nce ntawm cov luam yeeb qis, qhov tsw siv hauv cov luam yeeb lim thiab diluted tau txo qis, ua rau kev txhim kho tsw tseem ceeb. Cov tshuaj tsw qab tseem ceeb hauv cov luam yeeb feem ntau yog cov tshuaj organic, thiab lawv cov kev cuam tshuam rau qhov tsw tau tshaj tawm ntau dua li cov luam yeeb thiab cov tshuaj ntxiv. Kev rho tawm cov tshuaj tsw qab no tshwj xeeb rau kev txhim kho kev haus luam yeeb tsw tau tshwm sim los ua ib qho kev daws teeb meem tseem ceeb rau cov teeb meem cuam tshuam nrog cov khoom lag luam luam yeeb qis.
Txij li muaj ntau yam ntawm cov tshuaj tsw qab no yog cov cua sov-rhiab heev thiab ua rau volatilization, supercritical extraction-paub rau nws qhov kev ua haujlwm kub-tau dhau los ua ib qho zoo tshaj plaws rau lwm txoj hauv kev xws li chav distillation thiab organic solvent extraction. Cov roj tseem ceeb yaj tshwj xeeb tshaj yog zoo nyob rau hauv supercritical CO₂, ua rau txoj kev no tshwj xeeb tshaj yog siv tau. Txhawm rau kho qhov kev rho tawm thiab txhim kho cov txiaj ntsig ntawm cov roj yam tseem ceeb, cov neeg ua haujlwm zoo li ethyl acetate qee zaum siv. Cov entrainers tuaj yeem txo qis solubility thiab txhim kho kev xaiv, yog li ua kom cov txiaj ntsig ntawm cov roj tseem ceeb extraction.
Los ntawm supercritical extraction, cov roj yam tseem ceeb zoo ib yam li cov khoom siv luam yeeb tuaj yeem muab tau thiab ntxiv rau cov luam yeeb. Cov txheej txheem no tsis tsuas yog txhim kho qhov muaj txiaj ntsig ntawm kev haus luam yeeb, tab sis kuj ua rau nws cov ntxhiab tsw qab, ua rau kev txhim kho kev haus luam yeeb tag nrho.