桂圆酵素制备及其抗氧化性研究

Preparation of longan enzyme through fermentation and its antioxidant activity

桂圆酵素以桂圆水提液为发酵底物,选择益生菌为发酵菌种进行制备。以胞外多糖含量为评价指标,对发酵工艺进行研究,通过单因素试验和正交试验确定最佳发酵工艺条件:发酵底物浓度9%、接种量9%、菌种比例(保加利亚乳杆菌:嗜热链球菌:嗜酸乳杆菌:青春双歧杆菌=1:1:1:2)、发酵时间8 d,在此条件下制备的桂圆酵素原液胞外多糖含量达1.1086 mg/m L。抗氧化性研究结果表明,桂圆酵素原液具有DPPH自由基清除能力、羟基自由基清除能力及超氧阴离子自由基清除能力,具有一定的抗氧化活性。

Longan juice was used as the culture to process the Iongan enzyme through fermentation. Four probiotic strains of bacteria （Lactobacillus bulgaricus, Streptococcus thermophiles, Lactobacillus acidophilus, Bifidobacterium adotescentis） were selected as fermentation agents. The efficiency of fermentation processing technique was measured by the exopolysaccharides produced. The optimum fermentation conditions were confirmed by single factor experiments and orthogonal experiment as follows： concentration of culture medium 9%, inoculums 9%, fermentation time 8 days, the proportion of various bacteria strains 1：1：1：2. The exopolysaccharides produced through of longan juice fermentation processed under the optimum fermentation was 1.1086 mg/mL. Excellent antioxidant activity of longan enzyme was confirmed by the antioxidant capacity tests.