Preparation of Herbal Tea Fermented by Lactobacillus from Lonicera japonica leaves and Analysis of Its Antioxidant Activity

In order to obtain a kind of Lonicera japonica leaves herbal tea with strong antioxidant activity and high health care, an orthogonal array design based on single factor experiments was employed to examine the influence of time, temperature, inoculum amount of L. plantarum 758 and the concentration of sugar (The mass ratio of glucose to sucrose was 3:2) on the fermentation process. The antioxidant and volatile components of Lonicera japonica leaves herbal tea were compared with those of three common herbal tea in the market. Results showed that the optimal fermentation conditions were determined as fermentation of Lonicera japonica leaves extract containing 7% sugar added at 38 ℃ for 24 h with an inoculum amount of 4%. Under these conditions, the chlorogenic acid content of Lonicera japonica leaves herbal tea reached 7.11%, the total flavonoids content was 22.51%, the DPPH free radical clearance rate was 84.23%±3.32%, and the ABTS free radical clearance rate was 85.30%±2.14%, which were significantly higher than those of the three kinds of herbal tea on the market (P<0.05). There were 32 kinds of volatile substances in Lonicera japonica leaves herbal tea, and their types and contents were higher than those in other comparison groups. Overall, the antioxidant capacity of Lonicera japonica leaves herbal tea fermented by L.plantarum 758 is outstanding, and it has higher nutritional value and practical function.