Simultaneous nitrogen-blow distillation extraction: A novel approach for aroma extraction of white tea

In the present work, a simple and efficient method for distillation and simultaneous extraction of essential oils from white tea, called simultaneous nitrogen-blow distillation extraction (SNDE), was developed using nitrogen-blow extraction equipment. The effect of SNDE on compounds and characteristic of white tea extract were investigated in comparison with simultaneous distillation and extraction (SDE), and the extraction conditions of SNDE were optimized by response surface methodology (RSM). Volatile compounds of white teas were extracted using SNDE and SDE, and analyzed with gas-chromatography-mass spectrometry (GC-MS). Quantitative descriptive analysis of white tea extract aroma showed that in SNDE, sweet, roasted and woody aroma were significantly declined compared with SDE; whereas grassy green and pekoe aroma were more similar to the sensory profile based on sensory evaluation method. Aroma metabolites analysis showed that alcohols, aldehydes, ketones, esters, heterocyclics and alkanes exhibited significant variations. The present work demonstrated that SNDE is an effective tool for the extraction and analysis of white tea volatile, which could truly reflect the quality characteristics of sensory aroma.