This study examines the effect of addition free and microencapsulated jujube extract (1, 3, 5 and 7%) to dark chocolate formulation on physicochemical properties of obtained dark chocolate. Production of microcapsules was done by coacervation between casein and pectin. After producing microcapsules, particle size and FTIR are applied for evaluation properties of resulted microcapsules. Dark chocolate was made by addition of cocoa butter, sugar and cocoa powder (control sample). Different amounts of jujube extract (1, 3, 5 and 7%) in free or encapsulated forms were added. Then physicochemical properties of dark chocolate such as total phenolic compounds, antioxidant activity, sensory properties, color indexes, texture analysis and morphological characteristics are evaluated by scanning electron microscopy. The results showed that the microcapsule particles size range was 3.11-261.17nm. This implies that the suitable coacervation method for production of microcapsules was chosen. Determination of total phenolic content and antioxidant activity of dark chocolate including jujube extract (free or microcapsules) showed control samples had the lowest magnitude of total phenolic content and antioxidant activity (P < 0.05). In sensory evaluation, samples containing 5% jujube free extract and 7% jujube microcapsule extract earned the highest acceptance by panelist in hedonic ranking sensory evaluation test. Investigating the color indexes of the samples showed the addition of jujube extract (free or encapsulated) influencing the color indexes of dark chocolate samples (L^*, a and b^*). Higher addition of jujube extract (free or microcapsules) cause more changes in all color indexes of dark chocolate (p < 0.05). Moisture content of samples is also affected by addition of the jujube extract. Addition of the extract resulted in increase of the moisture content of samples but in all samples the moisture content was in the standard range (up to 1.5%). The acidity of chocolate samples increased with increasing amount of jujube extract. The texture of samples had influenced the addition of jujube extract as the firmness of samples was reduced. Morphological observation showed a uniform structure in the samples containing jujube extract (both free and microcapsulated).

dark chocolate, jujube extract, encapsulation.