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. 2025 Dec 3;10(1):1.
doi: 10.1038/s41538-025-00638-x.

Initial allergenicity assessment of Ulva sp. seaweed flour

Odeya Kedar  1 , Alexander Golberg  2 , Uri Obolski  3 , Efraim Steinbruch  2 , Alexander Chemodanov  2 , Álvaro Israel  4 , Yoav D Livney  5 , Idit Lachover-Roth  6   7 , Yossi Rosman  6   7 , Ronit Confino-Cohen  8   9
Affiliations

Initial allergenicity assessment of Ulva sp. seaweed flour

Odeya Kedar et al. NPJ Sci Food. .

Abstract

Ulva sp. is a green marine macroalga and a promising yet underexplored sustainable food source, with limited research on its allergenicity. This study evaluated the allergenic potential of Ulva sp. demineralized biomass flour (Ulva-DBF) using a weight-of-evidence approach inspired by regulatory assessments for novel foods, combining literature review, proteomic analysis, and a pilot clinical trial. Literature revealed no documented Ulva allergenicity. Proteomic analysis identified a few putative allergens, with estimated allergenic potential below 0.02%. In a pilot clinical trial (registered at ClinicalTrials.gov, Identifier: NCT06452381; First Posted Date: June 11, 2024), 31 participants consumed Ulva-DBF. No allergic reactions occurred, although 16.6% reported gastrointestinal discomfort. These findings represent a preliminary evaluation phase before widespread exposure. Nevertheless, large-scale consumption remains the most effective way to assess public health risks associated with any food. As we seek innovative and sustainable food solutions, post-marketing monitoring is vital to ensure their safety.

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Conflict of interest statement

Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Allergenic protein differences in Ulva before (Ulva-UW) and after processing (Ulva-DBF).
a Proteins detected uniquely in Ulva-UW. 39 proteins were detected uniquely in Ulva-UW, with non-zero Intensity-Based Absolute Quantitation (iBAQ) values in Ulva-UW but absent (zero iBAQ) in Ulva-DBF. Several of these proteins showed homology to known food allergens, indicating that processing may reduce the abundance of potentially allergenic proteins. b Proteins detected uniquely in Ulva-DBF. 22 proteins were detected uniquely in Ulva-DBF, with non-zero iBAQ values in Ulva-DBF but absent in Ulva-UW. Among these, one protein was homologous to the Collagen alpha allergen. Light blue bars denote proteins detected in Ulva-UW and Ulva-DBF, respectively, and dark blue bars represent proteins with allergen homology. Allergen names are shown within the bars for clarity.
Fig. 2
Fig. 2. Analyzing protein allergenicity from a proteomics file using online databases.
The databases utilized include: NCBI: Comprehensive biological information repository (https://www.ncbi.nlm.nih.gov/). AOL: Peer-reviewed allergen database for homology searches (http://www.allergenonline.org/). WHO/IUIS Allergen Nomenclature Database (Allergen.org): Source for expert-reviewed allergen data and standardized nomenclature (http://allergen.org). This study utilized the AOL “Sliding 80mer Window 36 search” method (http://allergenonline.org/databasefasta.shtml, http://www.allergenonline.org/databasehelp.shtml) to compare proteins to allergens in the database. This process generated homology scores for both the Sliding 80mer Window and full-alignment sequence, alongside allergen names. Our output was organized by biochemical and allergen names, with duplicates removed and food allergens consolidated if their sliding 80mer window sequences exceeded 35%.
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References

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