Characterization of key aroma compounds in four algae species using sensomics approach

Algae are gaining attention as sustainable alternative protein source with environmental and nutritional benefits. However, their flavor limits consumer acceptance. This study used a sensomics approach to analyze the aroma profiles of four algae. Sensory evaluation results showed that Chlorella vulgaris exhibited pronounced grassy and earthy, while Spirulina platensis was earthy and fishy notes. Phaeodactylum tricornutum displayed marine-like and fishy odors, similar to Nori , but with stronger sulfurous and rubber-like. Consumer favored macroalga Nori over microalgae, with Phaeodactylum tricornutum slightly more favored than the others. Using gas chromatography combined with mass spectrometry, sulfur chemiluminescence detection, and olfactometry, 26 odorants with flavor dilution factors greater than 27 were identified. In Chlorella vulgaris , 2,3-dimethyl-5-ethylpyrazine and 3,5-diethyl-2-methylpyrazine had the highest odor activity values (OAVs), while 2,3-dimethyl-5-ethylpyrazine and 2-pentylpyridine had the highest OAVs in Spirulina platensis . These compounds significantly contributed to earthy, grassy, and green odors. In Phaeodactylum tricornutum and Nori , ( E,Z )-2,6-nonadienal was the most important compound and correlated with fishy and marine-like odors. 1-Hexen-3-one, found exclusively in Phaeodactylum tricornutum , had the second-highest OAV and was linked to rubber-like and musty odors. These findings provide insights for future improvements in algae flavor and enhancing their consumer acceptability. • ( E,Z )-2,6-Nonadienal drives fishy aroma in Phaeodactylum tricornutum and Nori . • 1-Hexen-3-one uniquely contributes rubbery and pungent notes in P. tricornutum . • Pyrazines and 2-pentylpyridine are key contributors to earthy and grassy odors. • Nori showed the highest consumer preference among the four algae.