Lee & Kader [2] have shown that freezing also results in reduction of the vitamin C content. Thus, a study to verify the influence of freezing on vitamin C content in lyophilized fruits was also performed. Figures 4 and 5 show the vitamin C content for freeze-dried acerola and papaya, respectively, using different types of freezing before lyophilization. Concerning to acerola, there was a loss of 55% using freezing in the freezer, and 53 and 54% using N2 (l) and N2 (v). Therefore, for acerola the type of freezing did not influence the vitamin C content in the freeze-dried product. However, for the papaya frozen in the conventional freezer there was a reduction in vitamin C content of 13%, while for samples frozen in N2 (l) and N2 (v) the
reduction was of 5%. This result was expected, since the degradation of ascorbic acid is greater when material is exposed for long time periods to low temperature ambients.