Agglomeration Process of Spirulina platensis Powder in Fluidized Bed Improves Its Flowability and Wetting Capacity

Abstract

This study analyzed the physicochemical and flowability properties of Spirulina platensis biomass powder, obtained through the fluidized bed agglomeration process, with a focus on its potential application in the food industry. This process aimed to reduce fine particles and enhance their dispersion in liquids. The study explored different fluidization air temperatures (65-85 °C) and binder solution flow rates (1.5-2.5 mL/min), using a 30% maltodextrin solution (9 ≤ DE-value ≤12) as binder. Optimal results were achieved at temperatures of 75 and 85 °C and binder flow rates between 2 and 2.5 mL/min. Under these conditions, the yield exceeded 50%, producing agglomerated powders containing more than 56% protein, 5-7.5% moisture, and low water activity (less than 0.65). The agglomerated powders exhibited improved flowability, with the Carr compressibility index decreasing from 33.38% [raw material (RM)] to values below 20% (agglomerated powders) and the Hausner ratio decreasing from 1.5 (RM) to 1.25 (agglomerated powders). Additionally, there was a significant increase in average particle size, with a 3.5-fold increase in D50 (from 49.47 to 148.13-170.00 μm), faster wetting times (from 300 to 3-150 s), and a change in the color perception compared to the RM was also observed.