The aim of this work was to study the stability of ascorbic acid (AA) after encapsulation into calcium alginate matrixes by coacervation through: a) falling drop by dipping AA-sodium alginate solutions into CaCl₂ solutions (IAA method), and by atomizing the AA-sodium alginate solutions into CaCl₂ solutions (SAA method), followed by freeze-drying of the obtained capsules. Sorption isotherms for both types of products were determined at the water activity (a_w) range of 0.103-0.892, at 15, 25 and 35 ºC, by using the gravimetric method with saturated salt. The percentage of retention of AA was determined, after 15, 30, 45 and 60 days of storage at 25 ºC. SEM micrographs of the products were obtained and the volume of micropores was also calculated. The minimum integral entropy of the water molecules occurred at a_w = 0.234 in the falling drop method powders, whereas this parameter was observed at a_w = 0.706 for the atomised one. For both types of products, the maximum value of AA retention was observed at the a_w corresponding to the minimum integral entropy which occurred at higher moisture contents for SAA than for IAA materials.