EXPERIMENTAL STUDY OF VITAMIN C IN LEMON JUICE WITH FREEZE DRYING
The economy has became competitive, with impact on the industries of fruit juices which must advance in the sense of minimizing production costs and, at the same time, generating products that obey each time more rigorous patterns of quality. In this work liquid chromatography was realized to determine some quality characteristics in the final product, in this case lemon juice. Natural lemon juice and freeze drying lemon juice were analyzed to evaluate the influence of this drying process in vitamin C concentration. Endogenous dehydroascorbic acid was converted to ascorbic acid by precolumn reduction with dithiothreitol at neutral pH. Total vitamin C was determined by C18 reversed-phase column with the phosphate buffer mobile phase (pH 2.5), incorporating dithiothreitol to main vitamin C in reduced form, and UV detection at 254 nm.
