Estudo da secagem intermitente da microalga Spirulina platensis

Abstract

The constant growth of the world's population has led to the emergence of alternative forms of food. Through this scenario, the microalgae, main members of the phytoplankton, arise. This group of microorganisms have a great importance, since together with the aquatic macrophytes, they produce most of the O2 present in the atmosphere. Through the microalgae, several commercial applications are possible, among them: treatment of wastewater, obtaining compounds of interest of the chemical, food and pharmaceutical industries. Spirulina microalgae refers to a range of species that belong to the phylum Cyanobacteria, and these have been used for hundreds of years as a food source. Spirulina platensis is a microscopic blue-green, photosynthetic, unicellular, filamentous and prokaryotic microalgae with a spiral shape. It features high protein content, antioxidant compounds, phycocyanin and carotenoids, full B vitamins, minerals, antioxidants, vitamins A, E, absorbable iron, polyunsaturated fatty acids such as gamma linolenic acid. Although it has so many benefits, its use has a limitation: high humidity. For this, it is necessary to use a dehydration method in order for the biomass to reach moisture levels where the proliferation of microorganisms and their consequent degradation is no longer possible. The work in question used electromagnetic radiations like infrared and microwaves to dry the microalga. Dryings were performed either continuously or intermittently. The intermittence in both methodologies was characterized by the combination of higher temperatures and potencies with milder conditions. It was observed that in both methodologies it was possible to satisfactorily remove moisture from the material. However, the drying process promoted the degradation of the bioactive compounds studied in comparison to the microalga before drying. The use of intermittence was more adequate than continuous drying in several conditions, favoring the use of this technique even in those methodologies where the effect on the quality of the material was more intense.