Optimization of fermentation technology of functional lotus leaf tea by response surface-principal component analysis
Using lotus leaf as raw material,a functional lotus leaf tea was prepared by fermentation with strong-flavor(Nongxiangxing)Daqu.Using the total flavonoids content,total phenols content and sensory score as evaluation indexes,the effect of Daqu inoculum,fermentation time and tem-perature,initial sugar content on the quality of the functional lotus tea were analyzed by single factor tests and the response surface method-principal component analysis.The results showed that the optimal fermentation conditions were Daqu inoculum 8%,fermentation time 30 h,temperature 27 ℃,and initial sugar content 9%.Under the optimal conditions,the functional lotus leaf tea had strong flavor and unique taste,and the total flavonoids,total phenols contents and sensory score in functional lotus leaf tea were 30.17 mg/g,73.51 mg/g and 96.2 points,respectively.This study provided a theo-retical basis for the application of lotus leaf.