開發乳酸菌發酵之臺灣藜酸麵團

Abstract

隨著近年人們越來越關注健康，對於機能性食品需求有增加趨勢，探討增進食品營養及品質的方法成為一項熱門的研究主題。其中，探討酸麵團增加麵包營養性的研究逐漸的受到關注。許多文獻證實，經乳酸菌發酵的酸麵團可以增加麵團中抗氧化能力並改善麵包的質地。本實驗之目的期望能增加酸麵團的活性成分，開發出具營養價值的烘焙產品。本實驗選用臺灣藜 (Chenopodium formosanum)，臺灣藜為臺灣原生種假榖類植物。實驗針對23株常用於食品發酵之乳酸菌對臺灣藜進行發酵，以Lactobacillus casei BCRC10697發酵24 hr後能降低pH值至4.6且蛋白酶水解活性相較控制組提升1.88倍。藉由反應曲面法以總抗氧化能力作為指標最適化發酵條件。以發酵溫度33.5oC、果糖添加量7.7%及麵團轉換比332.8得最佳之總抗氧化能力為6.82 trolox mmole/kg。與未發酵臺灣藜相比最適化之臺灣藜總抗氧化力提升63%且DPPH自由基抑制能力約提升20%。隨後將發酵臺灣藜取代部分麵粉製成小圓麵包，添加20及25%之臺灣藜酸麵包其總抗氧化力為3.36 trolox mmole/kg，同時總多酚及總類黃酮含量分別為4.23 mg GAE/g、3.46 mg QE/g 比起未發酵之臺灣藜麵包組別提升了18%跟40%。質地分析結果中，添加酸麵團組別麵包整體硬度及咀嚼性提升。麵包在一般環境下的保存試驗中，酸麵團組別比起未發酵組別延長了約2天的儲藏期。經本實驗開發製成之臺灣藜酸麵團具有提升麵包之機能性及儲藏性，提供未來臺灣藜機能性食品開發之另一具潛力的加工形式。

With the increasing concern to health in recent years, exploring ways to improve the nutrition and quality of food has become an important subject. Among them, the increasing of bread nutrition by sourdough fermentation has gradually drawn attention to public. Many literatures have confirmed that sourdough fermented by certain lactic acid bacteria can increase antioxidant capacity, and also improve the texture. The purpose of this study is to enhance the bioactive compounds of sourdough and to develop a nutritionally valuable bakery product. Djulis (Chenopodium formosanum), a native plant of Taiwan, was utilized in this study. In this study we fermented djulis by 23 different lactic acid bacteria. Results showed Lactobacillus casei BCRC10697 can lower the pH value to 4.6 and increase proteolysis ability to 1.88 times relative to control after 24 hours fermentation. In addition, we used response surface methodology to optimize the trolox equivalent antioxidant capacity of djulis during fermentation. The condition was at temperature 33.5oC, fructose content 7.7% and dough yield 332.8, which showed the optimal result of TEAC 6.82 mmole /kg. Comparing to unfermented djulis, the optimal product increased 63% of TEAC and 20% of DPPH. Subsequently, the fermented djulis was replaced with a part of wheat flour to make bun. The bioactive compounds of total phenolic and flavonoid compounds were 4.23 mg GAE/g and 3.46 mg QE/g relatively comparing to unfermented djulis bread which increasing18% and 40%. In the results of texture analysis, hardness and chewiness of sourdough bread increased. In addition, shelf life of sourdough bread can extend approximately two days. This experiment developed the djulis sourbread with good functionality and shelf life, which provided potential processing way for developing the djulis functional food.