BIOCHEMICAL COMPOSITION AND FATTY ACID PROFILE OF THE MARINE MICROALGA Isochrysis galbana DRIED WITH DIFFERENT METHODS

Abstract

In this paper, the effects of different drying methods on proximate composition, pigment contents, and fatty acids profile of Isochrysis galbana were evaluated. The microalgae biomass was dried by freeze drying (FD), oven drying (OD), spray drying (SPD), and sun drying (SD) methods to identify the best procedure with the lowest negative impacts on the algae nutrient values including pigments, proximate composition, and fatty acid profile. The highest protein content was obtained in FD (62.200.15 %). Also, the lipid content of the dried microalga was significantly influenced by the drying process, while among all treatments, the highest and lowest values were measured in FD (13.770.42 %) and SD (11.680.16 %) samples, respectively (P<0.05). The highest chlorophyll a (0.9020.028 µg/mg), b (0.6050.007 µg/mg), and total carotenoids (1.0570.056 µg/mg) were observed in FD samples. However, the lowest levels of chlorophylls and total carotenoid pigments were obtained in SD and SPD, respectively. The lipid profiling analysis showed the highest level of polyunsaturated fatty acids (PUFAs) in FD method (41.51%), while the maximum saturated fatty acids were observed in SD (54.89%) followed by OD (51.41%). Also, the highest docosahexaenoic acid (12.41 %) were measured in FD compared to others (P<0.05). In conclusion, freeze drying method would be an efficient dewatering post-harvesting technique for the marine microalga I. galbana with the lowest impact on the nutritional quality in particular PUFAs content compared to the other studied drying methods.