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.