A familiar squeeze of tomato ketchup could soon deliver more than sweetness, acidity and a bright red finish. Researchers have developed a protein-enriched ketchup by incorporating extracts from the microalga Chlorella vulgaris, creating a condiment that preserved much of ketchup’s traditional sensory profile while increasing its nutritional content. In tests, formulations containing up to 3% algal protein were the most acceptable to tasters, suggesting that algae-derived ingredients may have a practical route into everyday foods.
The study, published in ACS Food Science & Technology, addresses a growing challenge in food innovation: how to add protein without compromising the taste, appearance or texture consumers expect. Protein enrichment has become common in cereals, snack bars, pasta and beverages, but condiments have received less attention. Ketchup, however, has several characteristics that make it a promising vehicle for functional ingredients. It is widely consumed, relatively shelf-stable and already contains strong flavors from tomatoes, vinegar, sugar, salt and spices that may help mask unfamiliar ingredient notes.
The researchers selected Chlorella vulgaris, a single-celled green microalga known for its high protein content and ability to grow rapidly. Unlike many conventional crops, microalgae can be cultivated throughout the year and may require comparatively less land and freshwater. These characteristics have made algae a subject of intense interest as a potential source of alternative protein. The nutritional promise is substantial, but algae-based foods can present sensory challenges, including grassy, marine or otherwise unusual flavors and green or brown color changes.
To create the enriched condiment, the team extracted proteins from C. vulgaris and blended them into ketchup recipes prepared with typical ingredients, including plum tomatoes, sugar, salt, vinegar, spices and citric acid. The formulations contained between 1% and 13% algal protein extract. After preparation, the samples were bottled and pasteurized, a heat-treatment step used to reduce microbial risks and improve product stability. A plain ketchup without added algae was also produced for comparison.
A sensory panel of 15 people then evaluated the samples. The results revealed a narrow but important range in which the nutritional benefits of the algae could be added without overwhelming the product’s identity. Ketchup containing 1% or 3% algal protein retained its familiar sweet, tangy and mildly spiced flavor, while the algal note remained subtle. The samples also maintained the reddish appearance associated with tomato ketchup, an important factor because color strongly influences expectations about flavor and freshness.
The picture changed at higher concentrations. At 5% and especially 13% algal protein, panelists detected a more pronounced algal taste, accompanied by a noticeable greenish shift in color. Although these formulations contained more protein, their acceptability declined. The findings illustrate a recurring problem in food science: increasing the concentration of a functional ingredient does not necessarily improve the product. Beyond a certain threshold, the ingredient’s own sensory characteristics can overpower the food it is intended to enhance.
Chemical and nutritional analyses showed that the 3% and 5% formulations contained approximately two to three times more protein than the plain ketchup. The enriched products also provided greater amounts of essential amino acids, the protein building blocks that the human body cannot produce in sufficient quantities on its own. The researchers reported increases in minerals, particularly sodium and iron, along with higher levels of antioxidant compounds. These results indicate that algal extracts can contribute more than protein alone, although the nutritional significance of each component would depend on serving size and the rest of a person’s diet.
The researchers’ approach is notable because it treats algae not simply as a replacement for animal or plant proteins, but as a concentrated functional ingredient that must be carefully balanced. Whey, soy and pea proteins are already used extensively in fortified foods, yet their production can involve agricultural land, water and energy demands. Microalgae may offer a more resource-efficient alternative in some production systems, but the environmental advantages will depend on cultivation methods, processing energy, water use and the scale of manufacturing. The study therefore points toward a promising ingredient rather than proving that every algae-based product is automatically sustainable.
The next steps will be essential before protein-enriched ketchup can move from the laboratory to supermarket shelves. Larger and more diverse consumer studies could determine whether the preferences observed among the 15 tasters hold across different age groups, cultures and dietary habits. Researchers also plan to investigate shelf life, stability during storage and the feasibility of commercial-scale production. For now, the results suggest that a modest amount of algal protein—particularly around 3%—may offer the best compromise: enough to raise nutritional value while keeping the taste, color and familiarity that make ketchup one of the world’s most recognizable condiments.
Article Title: Protein-Enriched Ketchup Gets Its Boost from Algae Extracts
News Publication Date: 2 July 2026
Web References: https://doi.org/10.1021/acsfoodscitech.6c00450
References: ACS Food Science & Technology, DOI: 10.1021/acsfoodscitech.6c00450
Image Credits: Adapted from ACS Food Science & Technology 2026, DOI: 10.1021/acsfoodscitech.6c00450
Keywords
Algae, Chlorella vulgaris, algal protein, protein-enriched foods, ketchup, food science, sustainable protein, functional ingredients, nutrition, antioxidants
Tags: Algae protein enrichment in ketchupenvironmentally friendly protein sourcesfood technology in condiment formulationfunctional food developmentincorporation of microalgae into everyday dietsmicroalga Chlorella vulgarismicroalgae cultivation benefitsnutritional enhancement of condimentsplant-based protein sourcessensory acceptance of algae-infused foodsshelf-stable functional foodssustainable food innovation
