老鹰茶发酵饮料及抗氧化活性研究

以老鹰茶为原料，利用复合乳杆菌发酵制备老鹰茶饮料，研究发酵工艺对老鹰茶抗氧化活性的影响。以发酵液初始pH、接种量和发酵时间为考察因素，以发酵液DPPH自由基清除率为响应值，通过响应面法优化发酵工艺，并对发酵前后体外抗氧化能力和总黄酮含量进行测定。结果表明，发酵液初始pH为5，接种量为2%，发酵时间16 h，该条件下发酵的老鹰茶DPPH自由基清除率可高达84.54%±1.28%，较发酵前47.15%±0.97%有显著提升；OH自由基清除率、超氧阴离子自由基清除率、铁离子还原能力（吸光度）也分别由发酵前的36.50%±0.55%、20.15%±0.33%、0.90±0.01提高到51.21%±0.81%、39.46%±0.25%、1.10±0.02；总黄酮含量由发酵前（0.14±0.01）mg/mL提高到（0.19±0.01）mg/mL。

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.