- 學位論文
食品級米麴菌發酵蕎麥之抗氧化與ACE抑制活性探討
Antioxidative and ACE Inhibitory Activities of Extracts from Buckwheat Fermented by Aspergillus oryzae BCRC 32288
摘要
蕎麥中含有類蕎麥肌醇、蕎麥鹼、芸香苷和斛皮素等類黃酮物質等營養成分，賦予蕎麥具有抗氧化、抗發炎、降血脂、降血糖及降血壓等藥理特性，因此蕎麥為現今深具潛力之機能性食品素材來源。本研究利用食品級米麴菌Aspergillus oryzae BCRC 32288進行蕎麥基質的固－液態發酵培養，並探討發酵時間(0、3、5、7、9、11、13天)對米麴菌發酵蕎麥水萃取物之抗氧化活性與血管收縮素轉化酵素(ACE)抑制活性的影響。實驗結果顯示，經米麴菌發酵後蕎麥萃取物之抗氧化活性較未發酵者為佳，而且經3天發酵時間以上之蕎麥萃取物的DPPH自由基清除活性(RSA%)皆可達到約90%以上，其中以經13天發酵後蕎麥萃取物之DPPH清除能力(EC50為19.82% 原萃取物)為最佳。此外，還原力與總酚含量方面，分別以為經5天與7天發酵後蕎麥萃取物之抗氧化活性為最佳，其最佳還原力與總酚含量值分別約為0.38mg vitamin C等值/mL與0.39mg GAE (gallic acid等值)/mL。在ACE抑制活性方面，未發酵蕎麥萃取物之ACE抑制活性較經米麴菌發酵者為佳，而且經米麴菌發酵蕎麥萃取物之ACE抑制活性的IC50值會隨著發酵時間增加而有上升的趨勢，可能由於發酵時間增加而促使米麴菌發酵蕎麥所產生較多的代謝產物，因此降低對ACE抑制活性的能力。最後，米麴菌發酵蕎麥的水萃取物雖無法提升具有對ACE抑制活性的能力，但卻有顯著地提升其抗氧化活性功能，因此可藉此發展成具有抗氧化活性機能性的健康食品。
並列摘要
Buckwheat is a very interesting species and recognized as a valuable source of so called “functional food”, because of the high biological nutritive value of its seed protein.In recent years, researches have revealed that buckwheat has therapeutic effects on diabetes, hypertension, hyperlipemia, etc. Because it is rich in nutrients and pharmaceutical ingredients including flavonoids (such as rutin, quercetin,etc.), fagopyritols (suchas D-chiro-inositol,etc.), fagopyrins, thiamin-binding protein. In this study, the antioxidative activites (DPPH free radical scavenging activity, reducing power and total phenolic contents) of the extracts from buckwheat fermented by GRAS (Generally recognized as safe) Aspergillus oryzae BCRC 32288 in solid-liquid cultivation were investigated. Among the extracts, the antioxidative activites of the fermented samples were higher than those of the unfermented ones. After 3 days of fermentation by A. oryzae, the DPPH radical scavenging activity (%RSA) of the extracts was about 90% or more. In addition, the highest values of reduced powder and total phenolic content of the samples with 5 days and 7 days, respectively, of fermentation by A. oryzae were about 0.38 mg/mL Vit.C E(equivalent) and 0.39 mg/mL GAE (gallic acid equivalent). In ACE inhibitory activity, IC50 values are on the rise more than seven days of fermentation. Is presumed during fermentation produce secondary metabolites affects the ability to inhibit the activity of the ACE. This experiment confirmed that Aspergillus oryzae fermentation extract of buckwheat can not upgrade the ACE inhibitory activity of ability, but significantly improved antioxidant function. So it still can develop into functional health food.