Effect of process conditions and carrier concentration for improving drying yield and other quality attributes of spray dried black mulberry (Morus nigra) juice

Abstract

The objective of this work was to study the influence of spray drying conditions on the physicochemical properties of black mulberry (Morus nigra) powder. A lab-scale spray dryer was employed for the spray drying process and maltodextrin DE=9was used as carrier agent.Response surface methodology (RSM) was performed to examine the effects of independent variables on the drying yield, color change, and total anthocyanin content and to determine the optimum processing conditions. Independent variables were: inlet air temperature (110 ºC, 130 ºC, and 150 ºC), compressed air flow rate (400, 600, and 800 l/h), and maltodextrin concentration (8%, 12%, and 16%). For each response, second order polynomial models were developed using multiple linear regression analysis. Analysis of variance was performed to check the adequacy and accuracy of the fitted models. The optimal conditions for drying yield and total anthocyanin content correspond to: temperature= 130 ºC, maltodextrin concentration= 8%, and compressed air flow rate= 800 L/h; these parameters led to the total anthocyanin content, process yield and browning index values of 5.85 (mg/100mL), 75%, 58.57% respectively.