Composition Analysis of Litchi Juice and Litchi Wine

Abstract

In this study the total components of the litchi juice and litchi wine in the brewing process were analyzed with both a low temperature (13-16 °C) and a long time (8-10 days) for fermentation. 161.4 g/l total sugar, 2.2 g/l total acids and a high content of Vitamin C (354.12 mg/l) and K (1251.8 mg/l) were found in litchi juice and highly dried extract (25.6 g/l), low volatile acid (0.36 g/l) and low higher alcohols (0.048 g/l) were identified in the young litchi wine. The total free amino acid content in litchi wine (784.1 mg/l) was similar to that of grape wine (700-1300 mg/l). However the content of each single kind of amino acid in litchi wine was all at an average level (less than 50 mg/l). In total, 33 kinds of aroma compounds were identified in litchi wine by liquid-liquid extraction and GC/MS analysis, including 16 esters, 5 alcohols, 4 acids, 2 ketones, 1 phenol and 4 other chemicals. Ethyl octanoate (34.82%), ethyl decylate (15.41%), acetic ester (11.36%), ethyl hexoate (7.14%), acetic isopentyl ester (4.72%) and citronel ethyl acetate (1.94%) were the main constituents, which covered 75.39% and 93.03% of the total compounds and ester compounds, respectively. Content of higher alcohols was only 7.85%. A very interesting phenomenon was found in that no matter how much sulfurous acid was added and how much total SO2 content was observed in litchi juice or wine, the measured free state SO2 content was always below 10 ppm, which was quite different from that of grape wine.