發酵溫度影響Bacillus subtilis BCRC 14715發酵黑豆中機能性成分之改變

Abstract

本研究以黑豆為原料，接種Bacillus subtilis BCRC 14715進行固態發酵，探討不同發酵溫度 (35, 40, 45, 50°C) 於培養期間 (0, 6, 12, 18小時) 對黑豆中一些活性成分，包括異黃酮素、納豆激酶 (nattokinase) 、維生素K2、血管收縮素轉化酶抑制劑 (angiotensin- converting enzyme inhibitor, ACE inhibitor) 、超氧歧化酶 (superoxide dismutase, SOD) 及吡啶二羧酸 (dipicolinic acid, DPA) 變化之影響。 結果顯示，40及45°C為B. subtilis BCRC 14715在黑豆基質中之最適生長溫度。無論發酵溫度為何，黑豆之總異黃酮含量在發酵過程中皆逐漸降低，其中以在35℃下發酵者下降之趨勢最為顯著。經發酵後之黑豆，其醣苷配基 (aglycone) 形式之異黃酮素含量，隨發酵時間增長而有明顯上升之趨勢 (p＜0.05)，其中以在50°C下發酵之黑豆可獲得最高aglycone形式之異黃酮素。在各發酵溫度下，黑豆中β-葡萄醣苷酶 (β-glucosidase) 活性皆於發酵6小時達最大值，其後即呈下降之趨勢。此外，隨發酵時間延長，黑豆中納豆激酶活性、維生素K2含量、ACE inhibitor活性、SOD活性及DPA含量均逐漸提升。黑豆經發酵18小時後，以在35°C下發酵者可得最高之納豆激酶活性，維生素K2則是在45°C下發酵可獲得最大產量；黑豆於40及45°C下發酵可呈現較佳之ACE抑制活性及SOD活性；在50°C下發酵者，則可獲得最大之DPA產量。

In the present study, fermented black soybean was prepared with Bacillus subtilis BCRC 14715. The changes of some functional constituents of fermented black soybean, including isoflavone, nattokinase, vitamin K2, angiotensin- converting enzyme inhibitor (ACE), superoxide dismutase (SOD), and dipicolinic acid (DPA), during the fermentation (0, 6, 12, 18 h) with B. subtilis BCRC 14715 at various temperatures (35, 40, 45, 50°C) were investigated. The results revealed that the optimum growth temperatures of B. subtilis BCRC 14715 are 40－45°C in black soybean. The total content of isoflavone in black soybean decreased during fermentation, regardless of fermentation temperatures. The most marked change was observed at 35°C. Fermentation caused a significant increase (p＜0.05) in the content of aglycone, which enhanced with fermentation time. The highest level of aglycone was obtained in black soybean fermented at 50°C. Regardless of fermentation temperatures, the activity of β-glucosidase noted in black soybean reached the highest after 6 h of fermentation and then decreased progressively. In addition, nattokinase activity, vitamin K2 content, ACE inhibitor activity, SOD activity and DPA content of black soybean increased as the fermentation time was extended. Black soybean fermented at 35°C for 18 h exhibited the highest level of nattokinase activity, while the highest content of vitamin K2 and DPA was found in black soybean fermented at 45 and 50°C, respectively. On the other hand, a higher activity of ACE inhibitor and SOD was observed in black soybean fermented at 40 and 45°C.