Estudo do processo de aglomeração da cianobactéria Spirulina platensis em leito fluidizado visando aplicação em área alimentícia

Abstract

In view of the intense increase in research with a perspective for the development of food sources that are conventional and that are able to meet the population's demand, the cyanobacterium Spirulina platensis has stood out due to its nutritional properties, being a source of proteins, vitamins, minerals, pigments, between others. However, this cyanobacteria in powder form has fine particles, which leads to undesirable physical properties, such as low dispersion in liquids and poor flow, in addition to losses of fines in handling, limiting its industrial use. The fluidized bed agglomeration process is used to increase the size of fine particles, improving physical properties. Thus, the objective of this work was to study the agglomeration process of the cyanobacteria Spirulina platensis in a fluidized bed, in order to improve the physical properties of the powder, as well as to evaluate the quality of the agglomerated powder. The process study was carried out using a 22 full factorial design in order to identify possible improvements in terms of process, product quality and influence of operational variables. The planning tests were carried out varying the operational conditions of fluidization air temperature (65 - 85 °C) and binder solution flow rate (1,5 – 3,5 mL/min), which was a maltodextrin solution 30 % (m/m). The experiments revealed were process yield, humidity, average particle size (D50), fluidity, wetting time and water activity. The information studied revealed a powder that showed particle growth, moisture below 15%, powders with flow characterized as reasonable, improvement in wetting time and water activity below the value of 0,65. The powders were also characterized according to the color parameters, obtaining a decrease in the L* and b* parameters and an increase in the a* parameter and finally, characterized in the centesimal composition. The results revealed that the best process conditions were obtained using a fluidization air temperature of 85 °C with a binder atomization flow rate of 2,5 mL/min and a fluidization air temperature of 75 °C with an atomization flow rate of binder of 2,0 mL/min, making it possible under these conditions to obtain yields above 50%, as well as an agglomerated powder with high protein content with values above 56%, low moisture content (5,46% for the condition with temperature of 85°C and 6,51 - 7,4% for the condition with temperature of 75°C) which are within the tolerable limit established by ANVISA, good fluidity, increase in the average particle size by 3,5 times (from 49,47 μm to 148,13 - 170,00 μm) and improvement in wetting time (from 300 s to 3 - 150 s).