Immobilisation of the invertase enzyme by encapsulation extracted from the yeast Saccharomyces Cerevisiae in a calcium alginate gel was studied. Quantitative analysis of the enzyme solution (protein assay) using the Kjeldhal method showed that the 10-fold diluted enzyme solution contained 410g of protein/L and the 100-fold diluted solution contained 98 g/L. These results correlate well with those of the Biuret method and will be used in further studies. The study of the effect of the diameter of the calcium alginate beads on the immobilisation yield of invertase showed that the smallest beads, with a diameter of 2 mm, ensured the best immobilisation yield of the enzyme, which reached an average of 98.54%. Incorporation of the free and immobilised enzyme solution into a sample of syrup containing crystals and into unclarified pomegranate juice to determine their effect on the content of total polyphenols, flavonoids, anthocyanins, pranthocyanidins and its antioxidant activity was also studied.