Effects of drying method on chemical composition and physicochemical properties of Spirulina platensis

Abstract

The drying method affects the physical state, structure and chemical composition of Spirulina platensis, particularly its colour-related compounds exhibiting antioxidant activity. This study provides guidance on using drying methods to enhance the value chain of Spirulina. The results of the study demonstrated that the chemical composition and other physicochemical properties of Spirulina platensis were the least affected by freeze-drying at 30^oC, followed by heat pump drying at 50^oC, whereas hot-air drying at 50^oC had the greatest impact. Within the scope of the study, hot-air-dried Spirulina platensis exhibited the highest peroxide value and the fastest sedimentation rate in water. Among the used methods in this study, freeze-drying is the most suitable method to retain secondary metabolites such as phycocyanin in Spirulina platensis. However, heat pump drying can be effectively used as an alternative to freeze-drying to reduce production costs while maintaining the application value of Spirulina platensis, provided that antioxidant activity is not the primary concern compared with colour or nutritional value.