Momordica charantia L. belongs to Cucurbitaceae family, being commonly named bitter melon. It represents an important source of active principles with antidiabetic action. Juice of the fruits is known to exhibit hypoglycemic properties, being recommended to reduce blood sugar levels in patients suffering of diabetes mellitus. Our researches focused on studying two protein fractions from the juice of bitter melon fruits, compounds with proved hypoglycemic activity: polypeptide-p and peptide MC6. In order to preserve these biological active compounds we have proceeded to drying fresh juice from fruits through three different methods: pulverization drying, vacuum drying and lyophilization. For further qualitative analysis we have reconstructed the juice by rehydration. Separation of all protein fractions and identification of the two compounds from juices were realized by SDS-PAGE electrophoresis. Results have suggested that studied compounds have not been damaged by thermal treatments, which constitute good processing and preserving methods.