| 摘要: | 狼尾草台畜草五號 (Pennisetum purpureum Schumach.)，為行政院農委會畜產試驗所改良具有豐富酚類物質、花青素及高抗氧化力的牧草品種。本研究目的主要探討紫色狼尾草萃取液利用醋酸菌及酵母混合菌種發酵後對於抗氧化活性的影響。紫色狼尾草乾燥粉末以熱水萃取10分鐘，加入10%砂糖溶解，利用醋酸菌及酵母混合菌種在30℃下進行發酵15天，分別以不同比例 （1%、5%、10%）、不同發酵方式（靜置、振盪）進行實驗，待發酵結束後進行抗氧化物質檢測分析（總酚物質、類黃酮物質及單體、聚合花青素含量）、抗氧化能力試驗（清除DPPH能力測定、總抗氧化能力(TEAC)測定、還原力測定及螯合亞鐵離子能力測定）。結果顯示，紫色狼尾草萃取液經不同比例 (1%、5%、10% )靜置發酵後pH變化由5.4~5.5下降至3.13~3.23之間；抗氧化物質在10%組中總酚物質及類黃酮物質提升最多，5%組清除DPPH自由基能力最好，而1%組在抗氧化能力中呈現持續增加的趨勢；振盪發酵部分，經發酵後pH由5.1下降至2.42；抗氧化物質（總酚物質、類黃酮物質）分別提升208.73 mg GAE/ml、20.23 ug RE / ml，聚合花青素提升20.7%。在抗氧化活性方面，TEAC提高2.07mM，清除DPPH自由基能力提升5.64%，螯合亞鐵離子能力增加12.33%，還原力則無明顯差異。
本實驗結果表示紫色狼尾草萃取液在不同比例及發酵方式下經醋酸菌及酵母混合菌種發酵後，皆能提高抗氧化物質及活性。希望能將紫色狼尾草萃取液開發成具有功能性之發酵飲品，提高其應用性。
Pennisetum purpureum Schumach is a modified forage species of rich phenolic substances, anthocyanins and high antioxidant properties by the Livestock Research Institute council of agriculture executive yuan. In this study, purple napiergrass extract was fermented under different culture conditions using acetic acid bacteria and yeast mixed strains of antioxidant component and. antioxidant activity. Pennisetum purpureum Schumach dried powder was extracted of hot water for 10 minutes, an after adding 10% sugar, the mixed of acetic acid bacteria and yeasts were added for 30℃ fermentation for 15 days. Experiments were carried out in different ratios (1%, 5%, 10%) and different fermentation modes (static, shake). After the fermentation, the antioxidant component were detected and analyzed (total phenolic compound content (TPC) ,total flavonoid compound content (TFC) and monomeric anthocyanins content, polymeric anthocyanins content), antioxidant capacity test (seavenging DPPH radicals ability, trolox equivalent antioxidant capacity (TEAC), ferrous reducing antioxidant capacity (FRAC) and ferrous ion chelating ability). The results showed that the pH change of purple Pennisetum extract after different ratios fermentation (1%, 5%, 10%) was reduced from 5.4~5.5 to 3.13~3.23; the antioxidant component was in the 10% group. And total flavonoid compound increased most, 5% group had the best ability to scavenge DPPH free radicals, while 1% group showed a continuous increase in antioxidant capacity ; In the shake fermentation part, the pH decreased from 5.1 to 2.42 after fermentation; the antioxidant component (TPC and TFC) increased by 208.73 mg GAE/ml, 20.23 ug RE / ml, respectively, and the polymer anthocyanin increased by 20.7% In terms of antioxidant activity, TEAC increased by 2.07 mM, DPPH free radical scavenging ability increased by 5.64%, chelating ferrous ion capacity increased by 12.33%, and reducing power was not significantly different.
Therefore, this study suggests that the extract of purple Pennisetum could enhance the antioxidant substances and activities after fermentation by acetic acid bacteria and yeast mixed strains in different proportions and fermentation modes. It is hoped that the purple pennisetum extract can be developed into a functional fermented beverage to improve its applicability. |
