Study on the Responsion of Biochemical Composition of S. acuminatus Biomass during the Spray Drying Process

Spray drying is a very popular method for microalgal biomass drying, however, systematic research on the responsion of biochemical composition during the process of spray drying has not been addressed so far. This study investigated the influence of the inlet temperature and initial solid content on the biochemical composition of spray dried Scenedesmus acuminatus biomass. The fatty acid composition and contents of CHNS, lipid, carbohydrate, protein, starch and pigments were analysed to characterize the quality and bioactivity of dried product. Results showed that the moisture content of dried microalgal powder decreased with the increase of inlet temperature and initial solid content, and the lowest moisture content of 2.37% with a higher drying yield of 84% was achieved at the optimized inlet temperature of 220°C and initial solid content of 16%. The biochemical compositions of CHNS total lipids, carbohydrates, protein, starch and fatty acid were similar with those dried by freeze drying, and were barely altered during the process of spray drying. However, the pigment would be partly degraded as the inlet temperature increased, which could be alleviated by increasing the initial solid content of the microalgal suspension due to the protection of cell aggregates. Thermogravimetric analysis (TGA) further confirmed that spray drying didn’t affect the quality of proteins, lipids and carbohydrates, suggesting that spray-drying technique could be applied to S. acuminatus for the production of both biofuels and nutritional supplements. These results may serve as a reference for the selection of drying method, utilization of the nutritional components in S. acuminatus and selection of biochemical parameters for spray-drying performance evaluation.