Physicochemical, biochemical, and thermal properties of Arthrospira (Spirulina) biomass dried in spouted bed at different conditions

Abstract

Spirulina (Arthrospira) is a cyanobacterium and an excellent source of natural compounds. The dried biomass can be applied in functional foods or in pharmaceutical products; however, its biochemical and physicochemical properties are affected by the drying operation. In this work, the drying effect in Spirulina biomass in a spouted bed at different air temperatures (80, 90, 100, and 110 °C) was studied and was compared with conventional tray drying (55 °C). The dried products and the in natura sample were analyzed for total phenolic compounds, antioxidant activity, protein solubility, phycocyanin content, thiobarbituric acid (TBA) value, and color parameters. DSC, TGA, FTIR, and MEV of the samples were also performed. The results showed that the spouted bed dryer at 80 °C and the tray dryer at 55 °C were more suitable for Spirulina drying in relation to the pigments and the lipid oxidation, due to the lowest losses of phycocyanin and at the lowest TBA values. However, the highest values of antioxidant activity and proteins solubility and the lowest losses on total phenolic compounds were found in the spouted bed dryer at 100 °C, resulting in a product with the greatest thermal stability.