目的: 本實驗目的主要在比較各種水溶性纖維(蒟蒻,KGM、關華豆膠GG、三仙膠XG、鹿角菜膠CA、果膠P、菊糖I)經大鼠腸道菌作用後調節菌相的作用、發酵後上清液之抗氧化效果及其對腸道表皮細胞之細胞毒性及基因毒性。 方法: 實驗使用靜置發酵模式,將各種纖維(0.1% w/v)與大鼠糞便漿(0.5% w/v)在37℃厭氧狀態下發酵0、24、48小時,並在這三個時間點收集其發酵液測定pH值,並以螢光原位雜交技術測其總菌、Bifidobacterium spp.、Lactobacillus spp.、及Clostridium spp.。將發酵液離心取上清液測定抗氧化指標,如Trolox當量抗氧化能力(Trolox equivalent antioxidant capacity, TEAC)、清除DPPH自由基能力及螯合亞鐵能力。以Caco-2細胞模擬人類結腸細胞,將各纖維之發酵上清液與Caco-2細胞共同培養1及3小時,測定細胞存活率(%)。並將各纖維之發酵上清液與Caco-2細胞共同培養3小時後測定對H2O2誘發細胞DNA傷害之保護作用。 結果: 實驗結果發現發酵液pH值皆隨發酵時間延長而下降, I組(inulin)下降最快,其次為KGM、GG及P組。與control (無添加纖維) 組相比,各纖維發酵24小時後I組上清液Trolox當量抗氧化能力最高,48小時後GG、CA、P組最高;各纖維發酵48小時後清除DPPH自由基能力皆高於control組;螯合亞鐵離子能力方面,各組24或48小時後都沒有顯著差異。各纖維發酵後其糞便總菌數皆有增加的現象,發酵48小時後P組、I組Bifidobacterium spp. 菌數明顯高於control組,而Lactobacillus spp. 菌數則在KGM組中增加較多,且GG組(關華豆膠)具有明顯降低Clostridium spp. 菌數之效果。各纖維之發酵後上清液與control組相比顯示具有基因毒性試驗之保護效果,發酵24小時以I 組較果最好;48小時後則以KGM 組較果最好。 結論: 蒟蒻、關華豆膠、三仙膠、鹿角菜膠、果膠、菊糖經腸道菌作用之發酵產物有增加抗氧化作用並可能對腸道表皮細胞具有良好保護作用。
Aim: To investigate the antioxidative ability produced after 48 h in vitro fermentation of konjac glucomannan (KGM), guar gum (GG), xanthan gum (XG), pectin (P), in comparison with control (fiber-free) as negative control and inulin (I) as positive control, by rat fecal slurry. In addition, the changes in fecal microflora profile and the toxicity of culture supernatant to Caco-2 cells were investigated. Method: Fibers (0.1% w/v) and rat fecal slurry (0.5% w/v) were cultured for 24, and 48 h in anaerobic static fermentation system. The culture supernatant was determined for indices of antioxidative ability including trolox-equivalent antioxidative capacity (TEAC), DPPH radical-scavenging ability and iron-binding capacity. The effect of the culture supernatant on cell curvival and H2O2-induced DNA damage of Caco-2 cells were determined. Result: The fermentation of inulin for 24 h produced the greatest TEAC as compared to the control group while that of GG, CA and P for 48 h exerted the greatest effect among groups. The DPPH-scavenging effect was greater in each fiber group as compared to the control after 48 h of fermentation. There was not different in iron-binding capacity among groups at either time point. Pectin and inulin exerted greater promotive effect on fecal bifidobacteria count while KGM stimulated the greatest growth of lactobacillus. Guar gum significantly decreased the growth of clostridia. The fermentation of soluble fiber exerted protective effect on H2O2-induced DNA damage in Caco-2 cells. Inulin group and KGM group exerted the best effect after 24 h and 48 h of fermentation, respectively. Conclusion: The in vitro fermentation of soluble dietary fiber by fecal microflora produced antioxidative substances and reduced the antioxidative damage to Caco-2 cells