[Effect of storage on the levels of ascorbic acid and beta-carotene in freeze dried red guava (Psidium guayava L.)].

The retention of ascorbic acid, beta-carotene and sensory properties of freeze-dried red guava pulp stored during 18 months in hermetically sealed brown glass flasks, at room temperature (ca. 25 degrees C) was studied. The results showed that the losses during freeze-drying were of 8.13% for ascorbic acid and 0.63% for beta-carotene. During storage more pronounced losses of these elements occurred during the first six months, becoming progressively smaller and almost irrelevant at the end of the period. The sensory evaluation of the reconstituted pulp showed that the retention of flavor was good. A Gompertz curve was fitted to observe data and showed to be efficient in explaining the trend of reduction for both elements under study. The excellent retention of ascorbic acid, the relatively fair retention of beta-carotene during processing and storage of freeze-dried red guava pulp, and the good conservation of flavor of the reconstituted pulp are evidences of the importance of this process for preserving and storing fruit pulps.