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Effects of brewing solution pH on the extraction of functional components and antioxidant activities of Chin Shin Dah Pan tea (Camellia sinensis)
|Authors: ||Cheng, Ya-Yueh|
|Contributors: ||NTOU:Department of Food Science|
|Keywords: ||Chin Shin Dah Pan;pH值萃取;抗氧化;兒茶素|
Chin Shin Dah Pan;pH extraction;antioxidant activity;catechins
|Issue Date: ||2018-08-22T06:40:38Z
|Abstract: ||摘要 本研究以青心大冇品種製成之綠茶、紅茶為原料，分析一般成分與茶湯的理化性質及抗氧化能力。青心大冇綠茶水分為 3.0%、粗脂肪3.78%、粗蛋白 20.67% 、灰分 4.73%、粗纖維 19.06%，與紅茶之含量差異甚小，與一般綠、紅茶的含量亦相近。在不同 pH值萃取條件下青心大冇綠茶的可溶性固形物含量與導電度均較紅茶高，兩者均在 pH 3 時得到最高的導電度。綠茶比紅茶的茶湯明亮，L 值、W.I. 值隨著 pH 的上升而下降，顏色也越深。兒茶素類的萃取明顯受浸泡溶液的 pH 值影響，在 pH < 5的酸性條件下較中性和鹼性條件的萃取量高，且含有較多的順式結構之兒茶素，綠茶 pH 值保持在 3 - 5下萃取可避免兒茶素降解以及獲得到較多的兒茶素。青心大冇茶種製成的綠茶比紅茶含有更豐富的多酚、兒茶素與類黃酮等抗氧化物質，在 pH 3 的條件下，無論綠茶、紅茶的總酚含量最高，pH 7 時的含量最低。茶葉發酵程度及萃取溶液的 pH 值對茶葉的咖啡因含量沒有顯著影響。青心大冇茶具有強抗氧化性，所製綠茶之 DPPH 自由基清除能力與還原力較紅茶強，亞鐵離子的螯合能力則較弱。萃取溶液的 pH 值對 DPPH 自由基清除能力影響小，但在酸性條件下綠茶的還原力則較強，紅茶在 pH 值 3 時對銅離子有比較強的螯合能力，但對鐵離子則較弱。綜合研究結果顯示青心大冇茶湯之抗氧化能力與其多酚、兒茶素與類黃酮等含量具相關性。|
Abstract In this study, Chin Shin Dah Pan was used as raw ingredient for green tea and black tea. Proximate compositions, functional components and antioxidant activities of both tea were also studied. Chin Shin Dah Pan green tea contained 3.0% moisture, 3.78% crude fat, 20.67% crude protein, 4.73% ash, and 19.06% crude fiber, those showed no significant difference with black tea. The proximate compositions of both Chin Shin Dah Pan black tea and green tea are also similar to those of commercial tea. Green tea had higher levels of soluble solids and conductivity than black tea with different pH extraction. Both tea had the highest conductivity under pH 3 extraction. L value and white index in green tea were higher than black tea. The color went deeper with the increase of pH value. The catechins extraction was also significantly affected by the pH value in soaking solution. More catechins were extracted in pH value lower than 5, the fact showed that more total catechins and cis catechins were extracted in acidic solution than in alkaline and neutral solutions. The extraction pH lower than 5 could prevent the degradation of catechins and obtained more catechins. Green tea and black tea from Chin Shin Dah Pan have abundant polyphenols, catechins, flavonoids and other antioxidants. Both green tea and black tea have the highest phenolic content in pH 3 extract, and the lowest amount in pH 7. No significant effect on tea caffeine amount was found in different pH extraction. Chin Shin Dah Pan green tea had a strong antioxidant activity. Green tea has stronger DPPH radical scavenging ability and reducing power than black tea. On the other side, green tea has lower chelating ability of ferrous ions. The extraction pH in the solution showed no significant effect on DPPH radical scavenging capacity. Green tea has stronger reducing power under acidic solution. Black tea has stronger chelating ability of copper ions in pH 3 solution, but had weaker chelating ability of iron ions. The results showed the antioxidant activity of Chin Shin Dah Pan tea had good relationship with the contents of polyphenols, catechins, and flavonoids.
|Appears in Collections:||[食品科學系] 博碩士論文|
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