Optimization of the jet steam instantizing process of commercial maltodextrins powders Original Research Article

Several food powders are submitted to agglomeration in order to enhance their appearance, flowability, and above all, their wettability. This work evaluates the wet agglomeration process of maltodextrins of different degrees of dextrose-equivalent, DE 5–20, following a sequential strategy of experimental designs in order to produce granules with low dissolution time. Initially, a 2(5−1) fractional factorial design was carried out with the independent variables steam pressure (1.5–1.9 bar), feed powder rate (1.6–2.0 g/s), drying air temperature (100–120 °C), sucrose and glucose addition (0–10% w/w). The results indicate that an increase in the DE degree increases the number of significant independent variables (p ⩽ 0.05). The same levels used in the (25−1) fractional factorial design performed previously were adopted in a 23 central composite design that was composed of 11 experimental runs. The surface response analysis indicated that the region of interest for lower dissolution time was found with a steam pressure of 1.7 bar, feed powder rate at 1.8 g/s and two possible drying air temperature (93 °C or 127 °C). The dissolution times of the agglomerates were substantially lower than of the original powder. The different characteristics obtained for the agglomerated maltodextrins could be attributed to the influence of their molecular mass and, consequently, of the glass transition temperature.