Unsaturated fatty acids and cholesterol content in Bulgarian spirulina and chlorella dietary supplements

Abstract

Introduction: In modern days, there have been numerous applications of microalgae: from human and animal nutrition to cosmetics and the production of highly valuable molecules (e.g., fatty ac­ids, pigments, proteins, etc.). Spirulina and Chlorella algal meals are traditionally consumed in Chi­na, Japan, India, America and Africa South. Scientific studies suggest that one tea spoon of microal­gae dry powder daily promotes weight loss, lowers serum cholesterol and glucose levels, helps boost­ing the immune system etc. Microalgae are characterized by high protein and low lipid content. Nev­ertheless, algal lipids are comprised of large amounts of essential unsaturated fatty acids. The aim of the present study is to analyse total lipids and lipid classes, unsaturated fatty acids and cholesterol content in two commercial microalgae dietary products from the Bulgarian market. Materials and methods: Total lipids were extracted according to the Bligh and Dyer method. They were separated into neutral lipids, glycolipids and phospholipids by means of solid-phase extraction and thin-layer chromatography. Lipid classes were transmethylated and subjected to gas chromatog­raphy coupled with mass spectrometry. Cholesterol was analysed by high-performance liquid chro­matography after alkaline saponification with methanolic potassium hydroxide. Ultraviolet detector was used for cholesterol detection. Results: Total lipids accounted: 3.8 g per 100 g dry Spirulina powder and 5.1 g per 100 g Chlorella powder. Glycolipids were the main lipid class in Spirulina, while lipids in Chlorella were represent­ed predominantly by neutral lipids. In both species polyunsaturated fatty acid presented 50% of to­tal lipids. Conclusions: The presented results showed that Spirulina and Chlorella powders produced in Bulgar­ia contain high amounts of unsaturated fatty acids and low cholesterol levels which could confirm the high nutritional value of both microalgal species.