Flow behavior of cocoa pulp powder containing maltodextrin

Abstract

This study aimed to evaluate the influence of maltodextrin addition on the flow properties of cocoa pulp powder obtained by spray and freeze drying. Cocoa pulp samples received 15% and 30% (m m-1) maltodextrin DE20. Two drying methods were used, spray and freeze drying. Powder morphology was evaluated through scanning electron microscopy (SEM). Wall friction angle, bulk density and tapped density were determined. Carr index (CI), Hausner ratio (HR) and flow index (FI) were used to evaluate powder flow. The particles powders obtained by spray drying showed rounded shapes, whereas the freeze dried powder showed irregular shapes. Increased maltodextrin concentration in the samples altered the powder particle size by spray drying and powder particle surface by freeze drying. The powder by spray drying of the sample with 30% of maltodextrin showed smallest wall friction angles, 13.4 to 14.9. The powder by freeze drying of the samples with 15% and 30% of maltodextrin showed wall friction angles between 14.0 and 20.6. Regarding flow, the powders by spray drying containing 30% of maltodextrin showed the best CI, HR and FI, 24.88, 1.33 and 4.88, respectively, being considered an acceptable flow. According to CI, HR and FI values, samples with 15% of maltodextrin produced powder classified as difficult flow in both methods applied. The higher maltodextrin concentration in cocoa pulp, the lower agglomeration in the powder by spray drying and the smoother particles surfaces in the powder by freeze drying. The addition of maltodextrin to the samples, for both drying methods, improve the powder flow and decrease the powder cohesion.