Comparative nutrient and sensory analysis of eight different commercial Chlorella powders

Felix Melcher¹Tillmann Peest^1,2Diego Garay^1,2Florian Utz^3,4Michael Paper¹Lisa Obermaier⁵Jennifer Schneiderbanger⁶Max Koch⁷Daniel Garbe¹Tom Nilges⁷Thomas Becker⁶Michael Rychlik⁵Corinna Dawid^3,4Wolfram Manuel Brück⁸Nikolaus Isidor Stellner^1,2*Thomas Bartholomäus Brück^1*

• ¹Werner Siemens-Chair of Synthetic Biotechnology, Dept. of Chemistry, Technical University of Munich, Garching, Germany
• ²TUMCREATE Ltd., Singapore, Singapore
• ³Chair of Food Chemistry and Molecular Sensor Technology, School of Life Sciences, Technical University of Munich, Freising, Bavaria, Germany
• ⁴Professorship for Functional Phytometabolomics, School of Life Sciences, Technical University of Munich, Freising, Germany
• ⁵Chair of Analytical Food Chemistry, Technical University of Munich, Freising, Bavaria, Germany
• ⁶Institute of Brewing and Beverage Technology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Bavaria, Germany
• ⁷Professorship of Synthesis and Characterisation of Innovative Materials, School of Natural Sciences, Technical University of Munich, Garching, Germany
• ⁸Institut Life Technologies, University of Applied Sciences and Arts Western Switzerland, Sitten, Switzerland

A growing global population and climate change challenge conventional agriculture and global food safety. Microalgae are an emerging sustainable nutrient food resource, increasingly regarded as an important component for the human diet. The chlorophyte Chlorella sp. is regulated and commercialized for food applications. Commercial Chlorella preparations are either produced by heterotrophic fermentation or photoautotrophic cultivation in bioreactors or outdoor ponds. Products can differ significantly with regard to taxonomy of the production strain, changed genetic properties due to strain development, cultivation conditions, and downstream biomass processing methods. Notably, heterotrophic strains may be adapted to generate little or no photosynthetic pigments, resulting in yellow or white variant. In this study, eight different commercial Chlorella products from different EU suppliers were analyzed and compared regarding identity of the production strain, macro-and micronutrient profiles, sensory properties, as well as microbial load. The production processes featured different cultivation methods, production strains, genetic variants (yellow and white) and downstream processing methods. Data indicates significant variations between the Chlorella products. White and yellow Chlorella products showed different protein and taste profiles compared to green, photosynthetically competent wild type strains. We confirmed relatively high and stable protein concentrations but could detect variations in sugar and specifically lipid and vitamin profiles depending on strain, cultivation and downstream processing methods. The microbial load varied strongly between closed and open cultivation systems but was compliant with legislative (EFSA) specifications for all samples. The comparative nutrient- and sensory data set presented in this study will aid in selecting algae products for the development of innovative foods, thereby accelerating adoption and differentiation of algae food products.