不同溶液浸漬桑椹對花青素之萃取與萃取液呈色之影響

Abstract

色澤呈現是評估富含花青素之酒液及果汁等飲料最重要的項目之ㄧ，花青素非常不穩定，在溶液中易受pH氧氣、溫度、光線、醣類、抗壞血酸、酵素、金屬離子、二氧化硫及多酚化合物等因子的影響而使酒液或果汁飲料等色澤由鮮豔的紅紫色轉為不受歡迎的黃褐色。本研究之目的在探討不同萃取溶液對桑椹花青素萃取之影響，及萃取液呈色之穩定性。在桑椹浸漬酒及果汁的試驗中，添加12.5% Glucose的樣品在浸漬期間總花青素的含量均高於未添加之樣品，且色度合也較高；經過HPLC分析比對後發現本實驗之桑椹浸漬酒及果汁中花青素主要為Cyanidin-3-glucoside，其次是Cyanidin-3-rutinoside。填充氮氣處理之桑椹浸漬酒，貯藏40天後，其總花青素含量是對照組樣品的兩倍之多。以檸檬酸調整pH值之桑椹浸漬酒在pH3.5且添加37.5% Sucrose之樣品於貯藏60天後，有較高之總花青素含量；其中以pH3.0且添加37.5% Sucrose整體呈現出較佳之色澤。以不同比例之蒸餾水萃取桑椹中之花青素，果汁中花青素的含量會隨著萃取溫度的升高而增加，且有添加異抗壞血酸鈉500mg/L時總花青素含量均較未添加之樣品低。此外，在50oC、70oC及 90oC水浴萃取之桑椹果汁中，以70oC具有最高的色度比，褐變程度最嚴重。

Color is one of the most important factors to evaluate the enrichment of anthocyanins in wine and juice. However, anthocyanins is very unstable and is easy to makes the beautiful purple red color of wine or juice to turn into unpopular brown color under the influence of other factors such as pH, oxygen, temperature, light, carbohydrate, ascorbic acid, enzyme, metals ion, sulphate dioxide and polyphenol compounds. The objective of this study is to investigate the effects of different extraction solutions in the extraction of anthocyanins from mulberry liqueur and the stability of color during maceration. The results show that mulberry liqueurs and juice with 12.5% glucose addition elute more total anthocyanins and color density contents than the samples without glucose addition. According the result of HPLC analysis, the most abundant anthocyanins in the mulberry wine and juice is Cyanidin-3-glucoside and the second is Cyanidin-3-rutinoside. The total anthocyanins content in mulberry liqueur with filled nitrogen after the duration of 40 days storage is 2 times of the control sample. After adjustment of the pH value to pH3.5 by citric acid and addition of 37.5% sucrose, it was found that the total anthocyanins content of mulberry liqueur was higher after the duration of 60 days storage. The sample with pH3.0 and addition performed the best red color appearance. When extraction of anthocyanins from mulberry with distilled water, the total anthocyanins content increase when the extraction temperature increases. And the addition of 500 mg/L sodium erythorbate into the mulberry juice resulted in the lower total anthocyanins extraction when compared with the samples without sodium erythorbate addition. Moreover, the 70℃ has the highest tint value under the different temperature extract in the mulberry juice.