Application of Rosemary Extract to Improve the Color Stability of Liqueur

Abstract

　The important qualities required in a liqueur, a type of alcoholic beverage, are that it has rich taste and aroma and does not fade or precipitate. The appearance of liqueur is an important factor that determines its value. However, its color fades during distribution and storage because of exposure to light and heat, and this deteriorates its quality characteristics. The present study investigated the use of rosemary, which is known to inhibit the oxidation process during cooking, for maintaining the color of liqueur. A rosemary extract, obtained by extraction using 60% v/v alcohol, was added to a colored pseudo-liqueur beverage and the residual ratio of pigments was compared. It became evident that deterioration of the color of 10% liqueur could be prevented by adding rosemary extract. Moreover, the use of rosemary extract was more effective than that of vitamin C; however, the effectiveness depended on the pigment being studied. It is suggested that the strength of the anti-fading component of rosemary is reflected in the structure of each pigment used. Furthermore, the effects of rosemary extract on the flavor of liqueur were examined, and the undesirable components affecting the flavor were identified. Moreover, the changes in alcohol concentration during the extraction process were also investigated.