Effects of Different Processing Techniques on the Quality and Antioxidant Capacity of Dandelion Leaf Tea

In order to find the best processing technique for dandelion leaf tea, dandelion leaves were processed in a traditional process, heap fermentation and β-glycosidase enzymes fermentation to be dandelion green tea and black tea, respectively. The tea samples were subjected to color evaluation, the content of functional ingredients, aroma components and antioxidant capacity analysis, and sensory evaluation. Dandelion leaf tea fermented with β-glucosidase can obtain better color quality, while dandelion green tea without a fermentation process can retain higher content of flavonoids (1.42%), polysaccharides (7.23%), and protein (1.81%). Dandelion black tea fermented without β-glucosidase (PB) contained the most olfactory compounds, with 18 kinds of unique aroma substances (furfuryl alcohol, 5-methylfuran aldehyde, anisaldehyde, methyl acetate, methyl phenylacetate, 2-ethyl butyric acid, 2-methyltetrahydrofuran 3-ketone and 2,3-octanedione, etc). The tea mainly showed sweet, hawthorn, cocoa, meat, popcorn, and other pleasant aromas, resulting in its high aroma score of sensory evaluation. Moreover, T-AOC, DPPH·, and ·OH scavenging rates of PB were 3.87 mmol/L FeSO4·7H2O, 73.99% and 34.21%, respectively, with significant antioxidant capacity. The quality of dandelion leaf tea produced by different processing technology was different, and the heap fermentation technology would be more suitable for the production of dandelion leaf tea.