Developing spray-dried powders containing anthocyanins of black raspberry juice encapsulated based on fenugreek gum

Spray-dried powder of black raspberry juice was optimized using response surface methodology (RSM). The juice was prepared by dispersions formulated with different coating materials including maltodextrin (MD with DE 6%, 6.59-26.41%), fenugreek gum (FG, 0.33-1.17%) and microcrystalline cellulose (MCC; 0.66-2.34%). Scanning electron microscopy and analyzing laser diffraction particle size were successfully used to relate the microstructure and dominant mechanisms on the stable dispersions to achieve the highest quality powder. Perturbation and 3D surface plots were drawn for each of the responses from the mathematical models. Second-order polynomial models with high R-2 (0.972-0.989) values were constructed for each powder physicochemical properties namely yield, solubility, total anthocyanin content (TAC), and total phenolic content (TPC). The linear effect of MD concentration had a significant (p<0.05) term in all constructed models. The optimal conditions were: MD concentration of 20.0%, FG content of 0.93%, and MCC concentration of 1.74%. These optimum conditions were powder recovery of 82.72%, solubility of 82.2%, TAC of 280.76 mg Cy3G/100 mL and TPC of 2.0491 mg GAE/g dw. A high agreement between experimental and predicted values was found. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.