From breakfast cereal to pasta, many common types of foods contain ‘added protein’, but not many condiments. In an effort to change this, researchers set out to improve the nutritional value of a widely consumed shelf-stable condiment using a sustainable protein source. With a dash of algae protein, the tomato sauce’s nutritional value was improved by the functional ingredient while its familiar distinct flavour was maintained.
Although many protein-added foods get the enrichment from whey, pea or soy sources, the researchers wanted to try a potentially more sustainable alternative.
As reported in ACS’s Food Science & Technology, the enriched tomato sauce was developed by incorporating protein extracted from microalgae that is rich in protein.
“Chlorella vulgaris can be cultivated rapidly throughout the year using comparatively little land and freshwater, making it a potentially more resource-efficient protein source than many terrestrial crops,” said the corresponding author of the study, Parise Adadi.
Previously, another research team incorporated algae proteins into vegan seafood mimics, where the microalgae’s fishy taste complemented the squid-ring analogues that they 3D-printed and deep-fried. For tomato sauce, the challenge was adding algal protein in a way that wouldn’t change the condiment’s flavour.
The researchers accomplished this by extracting the proteins from C. vulgaris. Then they developed ketchup recipes containing 1 to 13% algal protein along with typical ingredients such as plum tomatoes, sugar, salt, vinegar, spices and citric acid. After they bottled and pasteurised the ketchup samples, including a plain ketchup with no added algae, a panel of 15 people tasted them.
A panellist reported a preference for recipes that contained up to 3% added algal extract, saying the samples maintained the sweet, tangy taste and reddish appearance expected of the condiment.
Compared to the plain tomato sauce, the samples with 3 and 5% algal extracts contained two to three times more protein, as well as higher amounts of essential amino acids, minerals — particularly sodium and iron — and antioxidants.
Tomato sauce recipes that contain 3% (left) or 5% (right) of algal protein extracts. Image credit: Adapted from ACS Food Science & Technology 2026, DOI: 10.1021/acsfoodscitech.6c00450
These results suggest that a moderate addition of algal protein could appeal to consumers and enhance nutritional value. The researchers’ future work will include larger consumer studies, shelf-life tests, and product development at commercial scales.
Top image credit: iStock.com/jabiru
