Red seaweed pigments as food colours and health ingredients
What it found
Red seaweed pigments called phycobiliproteins can colour foods pink to blue and have shown antioxidant, anti-inflammatory and other activities, mostly in lab and animal studies.
In people, evidence is still limited.
What they found
Animal and lab studies
Health activities in lab tests
In lab tests, these pigments have shown antioxidant, anti-inflammatory, anticancer, antibacterial and antiviral activities, and may affect metabolic disorders. The authors note this evidence comes mainly from cells and animals, with limited human data.
Other findings
What they are
Phycobiliproteins are water-soluble pigment proteins found in red seaweeds and cyanobacteria. The main types in red seaweed are R-phycoerythrin, R-phycocyanin and allophycocyanin, giving pink to red and blue to violet colours.
Colour in foods
These pigments dissolve easily in water and give vivid colour at low doses. R-phycoerythrin is the main red pigment in red seaweed, while blue colours in foods mostly come from a cyanobacterial phycocyanin, not from red seaweed.
Stability problems
The pigments are sensitive to heat, light, oxygen and pH. R-phycoerythrin is generally stable between pH 3 and 10 but can degrade above 40 °C, and phycocyanin is less stable above about 45 °C.
Season and growing conditions
Pigment levels in red seaweed vary with species, season, light, temperature and nutrients. In Gracilaria gracilis, R-phycoerythrin fell from 7 to 3.6 mg per gram dry weight between winter and autumn.
Extraction and purification
Getting high-purity pigment usually needs several steps, including cell breakdown, clarification and chromatography. Newer methods like ultrasound, enzymes and deep eutectic solvents can improve yields, but scaling them up remains difficult.
What the authors conclude
“Overall, red algal PBPs have considerable potential as dual-function ingredients, although commercialization requires advances in raw material standardization, stability-enhancement strategies, process optimization, clinical validation, and regulatory harmonization.”
Also in their conclusions
- They say red algal phycobiliproteins have considerable potential as dual-function ingredients.
- They advise that commercialization requires advances in raw material standardization, stability enhancement, process optimization, clinical validation and regulatory harmonization.
How it was done
Food companies want natural colours that also offer health benefits, but natural pigments often fade or break down during processing and storage. The authors reviewed red seaweed phycobiliproteins as possible dual-function food ingredients.
The authors gathered and compared recent studies on red seaweed phycobiliproteins, covering which seaweeds contain them, how they are extracted and purified, how stable they are in foods, what biological effects they have shown, and what rules apply. They focused mainly on studies from the last 10 years and included some cyanobacteria studies where red seaweed evidence was limited.
What it can’t tell you
- Most of the health effects have been seen in lab tests or animals, not in people.
- The review did not find enough human studies to show whether these pigments prevent or treat any disease in people.
- The authors note that clinical validation is still needed.
Who paid
- Funding
- Funded by Australian Research Council; Fisheries Research and Development Corporation (from the PubMed record).
- Conflicts
- The authors declare no conflicts of interest.
- Authors work at
- The University of Melbourne, Australia; Deakin University, Australia
The paper
- Title
- Red Seaweed-Derived Phycobiliproteins: Marine Bioactive Colorants with Functional Health Properties
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Sun Y, Zhou Y, Wang M, et al (2026). Red Seaweed-Derived Phycobiliproteins: Marine Bioactive Colorants with Functional Health Properties. Marine drugs. doi:10.3390/md24070246Free full textPubMed 42505986DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error