Effect of microencapsulation by spray drying on cocoa aroma compounds and physicochemical characterisation of microencapsulates

摘要

In this study the effect of microencapsulation parameters by spray drying on protecting volatiles of cocoa liquor, by employing Maltodextrin (MD) and Hi-Cap 100 (HC) as encapsulating materials, was evaluated. The feed solution were prepared in proportions of 3:1 and 2:1 w/w (wall:core) and drying at 150,180 and 210 degrees C. The microencapsulates were evaluated in terms of yield, moisture, water activity, tapped density, rehydration properties and color. The morphology and size of the microcapsules were determined by SEM and aroma retention was evaluated by using HS-SPME and subsequent GC-MS analyses. The yield values were between 32.65 and 58.77%, being higher for encapsulated with HC. The microencapsulated powders showed moisture values between 1.05-4.00% dry basis and low water activity values, among 0.052 and 0.269, what make them appropriate for their use in the food industry. The microencapsulated powders with HC showed semispherical particles, smooth surfaces, and few deformations. In contrast, those obtained with MD showed a high number of surface irregularities (folds, shrinkage, or dents). Microencapsulted powders obtained with HC allowed a higher retention of cocoa aroma (22.6-32.5%), while MD solids showed lower values, between 12.1-19.2%. The major aroma retention was obtained with HC in 2:1 ratio and drying temperature of 210 degrees C. However, sensory analyses results showed preference by the microencapsulated with MD, 2:1 ratio and 210 degrees C, which exhibited similar characteristics to chocolaty drink when it was applied to 20% (w/w) in whole milk as a milk modifier. (C) 2017 Elsevier B.V. All rights reserved.