engleski

The effect of agglomeration on physical properties and bioactive compounds of cocoa drink mixtures prepared with various sweeteners.

Agglomeration is a process used to improve reconstitution properties of cocoa powders in liquids. This process has been used for instantization of numerous food products, due to its ability to improve dispersion and solubility properties of the powders while reducing the fines in the final product. The process also enables production of more attractive powdered products (both in appearance and sensory properties) and decreases the apparent density and tendency to cake during storage. In this study physical properties and bioactive content of powdered cocoa drink mixtures prepared from cocoa powders with two different fat contents and different sweeteners (sucrose, aspartame/acesulfame K and stevia), were investigated before and after agglomeration. Particle size and density characteristics of the formulated mixtures and agglomerates, as well as dispersibility and wettability were evaluated. Content and composition of polyphenols was determined using UV-vis spectrophotometry. Antioxidant capacity of cocoa mixtures and agglomerates was evaluated by using ABTS and FRAP assays. Agglomeration significantly affected physical and bioactive properties of cocoa drink mixtures. Total phenol, flavonoid and flavan-3-ol content, as well as the antioxidant capacity decreased after agglomeration of all cocoa drink mixtures. Both cocoa powder mixtures and cocoa agglomerates prepared with the cocoa powder containing higher fat content (16-18%) generally provided lower bioactive content, compared to the mixtures prepared with low fat cocoa. As expected, agglomeration resulted in agglomerates with higher median diameter and Hausner ratio values. Agglomerated cocoa mixtures also showed better reconstitution properties in comparison to non-agglomerated cocoa powder mixtures. Best results were obtained for cocoa agglomerates containing low fat cocoa. Results indicate that agglomeration improves the physical properties of cocoa drink mixtures, regardless of their composition, but negatively affects the beneficial bioactive constituents and thus requires further studies in order to improve characteristics of the final product.

agglomeration; cocoa; sweeteners; physical properties; polyphenols

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