Deodorization of three edible microalgae with a laccase-catechin mediator: Insights from E-nose, GC–MS and sensory analysis

Microalgae are a sustainable and nutrient-dense food source, but their strong off-flavors significantly limit broader consumption. This study evaluates the effectiveness of a laccase-catechin mediator in improving the odor profiles of Spirulina, Chlorella, and Chlamydomonas reinhardtii . Mediators were applied ex situ (pre-formed) or in situ (generated within the suspension). Ex-situ mediators, optimized at 40 °C for 2 h, achieved better deodorization compared to in-situ mediators, with optimal catechin dosages of 28, 16, and 8 mg/g biomass for Spirulina, Chlorella, and C. reinhardtii , respectively. Sensory evaluation showed reduced grassy, earthy, and fatty odors, and enhanced floral and fruity notes, with the ex-situ approach leading to higher overall acceptability. GC–MS analysis confirmed that mediators decreased the diversity and abundance of key odor-active volatiles in three microalgae species. Laccase-catalyzed quinone-type mediators effectively neutralize undesirable compounds, offering a promising enzymatic strategy for improving the sensory quality of microalgae-based foods, especially for sustainable food applications.