乳酸菌發酵檸檬汁之抗氧化活性

Antioxidant activities of lactic acid bacteria fermented lemon juice

張萍亞(Chapiya Chanbai)

指導教授 ： 吳明昌

國立屏東科技大學/國際學院/食品科學國際碩士學位學程/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00099

摘要

檸檬汁富含酚類化合物 (10.75 mg/g)特別是類黃酮 (0.57 mg/100 g)，其被證實具有重要抗氧化活性，能夠清除活性氧自由基 (ROS)。在這項研究中，乳酸菌 (LAB) 從泡菜中分離，並利用16S rRNA基因序列分析與TA cloning 序列進行鑑定。經過分析後，鑑定出 Lactobacillus plantarum, Lactobacillus casei, Lactobacillus acidophilus 及 Pediococcus pentosaceus，與數據庫相比有100%的相似性。利用以上四種菌株進行發酵培養，藉由改變 pH值、酸度以及糖含量，計算活菌數以及抗氧化能力測定。發酵時，葡萄糖含量明顯下降 (P<0.05)，果糖含量並沒有改變。所有的乳酸菌皆能在果汁中生長，在30℃，72小時之後，存活的菌數達到 7.0 log CFU/ml。結果顯示，在發酵期間，pH值與可溶性固形物含量明顯下降。檸檬汁藉由LAB乳酸菌發酵，具有更高的類黃酮與酚類含量。關於DPPH清除自由基能力測定 (以Trolox 抗氧化活性和還原能力分析)，選用益生菌發酵檸檬汁，其抗氧化活性顯著提高，其中Lactobacillus plantarum 在檸檬汁發酵時擁有最高之抗氧化活性。此研究結果顯示，利用益生菌發酵檸檬汁，將提高果汁的健康及營養益處。

關鍵字

檸檬汁發酵 ； 乳酸菌 ； 抗氧化活性 ； 總酚化合物

並列摘要

Lemon (Citrus limon (L.) Burms. f) juice containing phenolic compounds (10.75 mg garlic acid equivalent (GAE)/g) particularly flavonoids (0.57 mg/100g) have been reported to possess an important antioxidant activity toward radicals which can scavenge reactive oxygen species (ROS). In this study, lactic acid bacteria (LAB) stains were isolated and purified from Kimchi base on physiological characteristic and the phylogenetic of 16S rRNA sequence analysis and TA cloning sequences to typing stains. The results from analysis were identified as Lactobacillus plantarum, Lactobacillus casei, Lactobacillus acidophilus, Pediococcus pentosaceus by comparison in blast database with 100% similarity coefficient. Four different strains were used as starter cultures, change in pH, acidity, sugar consumption, viable cell count during fermentation and antioxidant properties were monitored. The amounts of glucose decreased significantly (P<0.05), meanwhile the fructose concentration did not change. All LAB strains were able to grow in the juice and their viable cell reached to 7.0 log CFU/ml after 72 h at 30oC. The results showed that pH were significantly decreased during the fermentation. Fermentation of lemon juice with LAB was reported higher the level of flavonoid and phenolic content. With regard DPPH radical scavenging activity, trolox equivalent antioxidant activity capacity and reducing power studied show that the fermentation of lemon juice using selected probiotic starters increased the antioxidant activity significantly, and the highest antioxidant activities were found in Lactobacillus plantarum fermentation. The results of this study showed that fermentation of Lemon juice by probiotic bacteria would enhance health benefit of the juice.

並列關鍵字

Lemon juice fermentation ； lactic acid bacteria ； antioxidant activity ； total phenolic compound

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