Nutrition and flavor analysis of Spirulina through co-fermentation with Lactobacillus acidophilus and Kluyveromyces marxianus and its effect on attenuating metabolic associated fatty liver disease

[Display omitted] •Fermentation significantly increased Spirulina antioxidant activity.•Nutritional and flavor profiles had better amino-acid ratios and sensory properties.•Fermented Spirulina effectively reduced HFD-induced hepatic fat accumulation.•Fermented Spirulina products have potential for prevention and treatment of MAFLD. Spirulina is widely known as the “Super Nutritious Food of the Future” due to its exceptional nutritional properties. In this article, we investigated the effects of fermentation using a combination of Lactobacillus acidophilus KDB-03 and Kluyveromyces marxianus GDMCC 2.119 on Spirulina. Fermentation significantly increased the total flavonoid and phenol levels in Spirulina, and enhanced the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity and ferric-reducing antioxidant power. Untargeted ultra-performance liquid chromatography-electrospray tandem mass spectrometry-based metabolomics and gas chromatography-ion mobility spectrometry analysis revealed alterations in the metabolites and flavor components of fermented Spirulina (FS). Furthermore, a mice experiment demonstrated that FS could effectively alleviate metabolism-associated fatty liver disease (MAFLD) by regulating liver metabolism, intestinal flora, and facilitating communication between the liver and gut. These findings suggest that fermentation could be a innovative approach to enhance the diversity of Spirulina products, and potentially be used as a strategy for the prevention and treatment of MAFLD.