Study on Fermentation Technology of Hawk Tea and Its Antioxidant Activity

The hawk tea was used as the main raw material, and the hawk tea fermented beverage was prepared by using Lactobacillus faecalis fermenting agent to explore the effect of fermentation process on the antioxidant activity of fermented beverage.Response surface method was used depends on initial pH value, inoculation amount, and fermentation time to optimize the fermentation process and the antioxidant capacity of fermentation liquid was measured in vitro. The results showed, the initial pH value of the fermentation broth was 5, the inoculation amount of the seed solution was 2%, and fermentation time was 16 h, under this circumstance, the DPPH free radical scavenging activity of the fermented beverage reached 84.54%±1.28%, which was significantly higher than 47.15%±0.97% before fermentation. Furthermore, OH radical scavenging rate, superoxide anion radical scavenging rate and iron ion reduction ability (absorbance) were also increased from 36.50%±0.55%, 20.15%±0.33% and 0.90±0.01 before fermentation to 51.21%±0.81%, 39.46%±0.25% and 1.10±0.02 respectively, and the content of total flavonoids increased from (0.14±0.01) mg/ mL to (0.19±0.01) mg/mL before and after fermentation.