硷性电解水之强硷性pH值及高还原性电位对食品系统之影响与抗氧化力

硷性电解水之强硷性pH值及高还原性电位对食品系统之影响与抗氧化力 鹼性電解水之強鹼性pH值及高還原性電位 對食品系統之影響與抗氧化力之評估 Effect of strong alkaline pH value and high reducing potential of alkaline electrolyzed water on food system and on antioxidative activity 研究生,柯姿廷 Ko, Tzu-Ting 指導教授,林頎生 Lin, Chyi-Shen 【摘要】 水經加鹽型及未加鹽型電解水器加以電解,可得高pH值、高還原性電位的鹼性電解水,其中加鹽型鹼性電解水因有添加電解質氯化鈉可促進電解,所以能較未加鹽型鹼性電解水具有更高的還原性電位及pH值。鹼性電解水之高pH值與高還原性電位會因與有機物作用而下降,其中還原性電位快速的消失。高pH值與有機物作用後仍有較高的最終pH值,具有類似緩衝的效果,可影響澱粉、茶湯、類胡蘿蔔素的物化性質。鹼性電解水可提高在來米粉、玉米粉及澄粉糊化後的黏度,也可提升其破裂及最初糊化溫度,然而,高的最終pH值會造成澱粉糊亮度降低。鹼性電解水沖泡 a值、b值明顯提高,色澤偏暗紅色,且EGC、EGCG、ECG、的烏龍茶湯,因具較高的最終pH值, EC含量較去離子水沖泡的烏龍茶湯低。高的最終pH值,亦能使類胡蘿蔔素萃出較為顯著,顯現較強的黃色度。實際應用鹼性電解水於食品調理上,其雖可促進稀飯的米粒糊化提高粘稠度,但感官品評由於受到鹼味影響,整體接受性並未比去離子水烹調者佳,應用於土司製程,除了有較深的烘焙著色外,對土司的質地並未有明顯的影響,但經儲放後,應用加鹽型鹼性電解水的土司硬度顯著較低,口感上也較有彈性。應用鹼性電解水所沖泡的烏龍茶,苦味較低,但對其茶香及甘味未有提升之效果,整體接受性也不如去離子水沖泡者佳。 鹼性電解水排除過氧化氫的效果以加鹽型鹼性電解水最高7.15,,未加鹽型鹼性電解水4.95,,而在DPPH自由基清除效果則幾乎不具。鹼性電解水呈現助抗氧化的能力,其添加於抗壞血酸溶液中可提升抗壞血酸的過氧化氫及DPPH自由基的排除效果,且依添加鹼性電解水還原性電位越高者清除效果越佳。在探討鹼性電解水之還原性電位對酵母菌,Saccharomyces diastaticus和Saccharomyces cerevisiae,的影響之模型試驗中,鹼性電解水還原性電位並無明顯的影響性,反倒是其鹼性pH值對酵母菌造成抑制作用,菌數隨著反應時間增加而降低。 關鍵字,鹼性電解水、pH值、食品調理、還原性電位 【Abstract】 Alkaline electrolyzed water (AEW) can be generated from an electrolyzer, with or without added NaCl, exhibits reducing potential and high pH value. With NaCl, the efficiency of electrolysis was promoted; the alkaline electrolyzed water resulted in higher reducing potential and pH value than without added NaCl. AEW reacted with organic materials, its reducing potential and pH value dropped; then reducing potential of AEW rapidly disappeared. However, pH value dropped slightly with buffering characteristic. Higher final pH value can affect the characteristics of starches, teas and carotene. Rupturing and gelatinizing temperatures of indica starch, corn starch and protein-free wheat starch were raised by mixed with AEW, and the viscosity of gelatinized solution increased, and the high final pH value made the solution darker. Cooled brewing oolong tea with AEW had higher final pH value resulting in higher a value and b value, appearing in dark red, and its EGC, EGCG, ECG and EC lowered than cooled brewing oolong tea by deionized water. With the high final pH value, the efficiency of carotene extraction was promoted resulting in deep yellow. Although sensory gelatinizing property of porridge rice can be enhanced by AEW, but overall acceptance was affected by AEW as compared with cooked by deionized water. In bread-making, textural property of bread wasn’t affected significantly, except the baked coloration was stronger. After storage, bread made by AEW electrolyzed with NaCl was lower in hardness and more elasticity in mouth feel. Although bitterness of oolong tea can be decreased by AEW, but its tea aroma and sweetness were not promoted. And its overall acceptance is not improved as compared with hot brewing by deionized water. AEW electrolyzed with NaCl showed the highest hydrogen peroxide scavenging activity 7.15,, and electrolyzed with no NaCl is 4.95,, but they were almost no DPPH radical scavenging activity. AEW can enhance L-ascorbic’s hydrogen peroxide and DPPH radical scavenging activity according added AEW with highed reducing potential. Reducing potential of AEW was no effect in yeast,Saccharomyces diastaticus and Saccharomyces cerevisiae,in the model system, but its high pH value resulted in decreasing yeast counts. Key s,alkaline electrolyzed water, pH value, food processing, reducing potential