Modeling and stability study of the anthocyanin-rich maoberry fruit extract in the fast-dissolving spray-dried microparticles

Transforming the anthocyanin-rich maoberry fruit extract (AE) into dry powder is a challenge due to its high sugar and alpha hydroxy acid contents. Moreover, anthocyanins in the sample are prone to instability. In the present study, the spray-drying conditions were studied for the microencapsulation of AE (Antidesma puncticulatum Miq.) in maltodextrin. Inlet air temperature, feed flow rate, and aspirator rate were defined as the independent variables, whereas microparticle recovery, accumulation of anthocyanins in the powders and residual water were dependent variables. A 2(3)-factorial, 6-axial, 6-centred central composite design was applied for developing a response surface, studying their effects on the desired dependent variables, and determining the best optimal condition. The optimal spray-drying conditions were an inlet air temperature of 140 degrees C, a feed flow rate of 6 mL/min, and an aspiration rate of 29 m(3)/h. There was no interaction between the AE extract and maltodextrin as analysed by the infrared spectroscopy. The microparticles preserved the anthocyanins and showed a more intense colour than the liquid extract during storage. The physicochemical characteristics (particle size, anthocyanins accumulated in the microparticles, residual water content, and thermal stability) of the developed microparticles were acceptable for nutraceutical application. Therefore, the application of optimal spray drying conditions causes the maltodextrin to enable the transformation of the gummy form of AE into the fast-dissolving dried microparticles with chemical stability improvement. (C) 2017 Elsevier B.V. All rights reserved.