Color changes of mei liqueur

• Main Authors: Shih-Chuan Liu, 劉世詮
• Other Authors: James Swi-Bea Wu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/88465613014285359107

博士 === 國立臺灣大學 === 食品科技研究所 === 91 === Mei (Prunus mume Sieb et Zucc.) can be soaked in spirit to make mei liqueur. Color is generally recognized as an essential quality attribute in alcoholic beverages. There are few scientific literatures concerning the making of mei liqueur and color changes. This thesis was to investigate the making of mei liqueur and the mechanism for browning in mei liqueur. Browning mechanisms of mei liqueur were studied using model solutions containing 28% ethanol in 0.1M citrate solution (pH 3.0) added with or without ascorbic acid, fructose, the predominant amino acid (asparagine), and catechin. The fact that no detectable browning occurred in all the samples containing no catechin shows the insignificance of Maillard reaction, ascorbic acid degradation, and caramelization. Therefore, the oxidation and condensation of tannins and fructose —catechin interaction may probably be the major mechanisms of browning in mei liqueur. The fractions of phenolic compounds of alcoholic extract by passing alcoholic extract through STRATATM SPE tube are incubating at 50℃. There is browning index changes at the fraction 2 which is analyzed the mayor phenolic composition is catechin with HPLC. We propose that in mei liqueur HMF formed from fructose, and then reacts with catechin-like phenolic compounds and results in browning. 　　Influencing factors to the browning reaction, which include pH, sugar species, metal ions, organic acid, ethanol concentration, phenolic compound and temperature were investigated. Result shows that fructose, citric acid, low pH value and high temperature promote fructose-catechin browning reaction. The activation energy of the browning pigment in catechin, catechin-gluctose, and catechin-fructose model solutions and alcohol extract is 6.82、6.42、6.51 and 5.22Kcal/mole, respectively. Higher temperature, lower phenolic compound, and higher oxygen content increase browning rate in alcohol extract. In mei liqueur making, ethanol at lower concentrations (30%) recovered more extract than at higher concentrations (60%). Higher ethanol concentration also extracted more phenolic compounds and resulted in higher browning index. Phenolic compounds, condensed tannin content and L value decreased while browning index, a value and b value increased during the aging process of mei-liqueur. We suggest the procedure of making mei liqueur is that washed, soaked in twice volume of 60% ethanol (w/v) around 60 or 90days and aged the alcoholic extract at least 90days.