Abstract:

The production of double screw extruded buckwheat tea was optimized by investigating the effects of three
extrusion parameters including extruder head temperature, screw speed and water content on total flavonoid content and
antioxidant capacity by single factor method and response surface methodology. The results showed that the optimum
process parameters were 79 ℃, 150 r/min, 24% for extruder head temperature, screw speed and water content, respectively.
The predicted and observed comprehensive evaluation scores of extruded buckwheat tea obtained under these conditions
were 7.47 and 7.39, respectively, suggesting good agreement. The prepared buckwheat tea had excellent brewing stability,
high clarity and perfect flavor. This study provides a technical support for dual-screw extrusion technology for the processing
of functional tea, and has a great potential for popularization.

Key words: buckwheat tea, extrusion, response surface methodology