Ketchup may one day offer more than its familiar sweet and tangy flavor.
Scientists have developed a protein-enriched version of the popular condiment using extracts from microalgae, potentially offering a more sustainable way to add nutrients to everyday foods.
The study, published in ACS Food Science & Technology, tested whether protein from the microalga Chlorella vulgaris could be added to tomato ketchup without ruining its taste, color or overall appeal.
Protein-enriched products have become increasingly common, appearing in foods such as breakfast cereals, pasta and snacks.
Most manufacturers rely on familiar protein sources such as whey, soy or peas. Researchers behind the new study wanted to investigate algae as another option.
According to corresponding author Parise Adadi, the goal was to improve the nutritional value of a widely eaten condiment using a sustainable source of protein.
Microalgae could have several environmental advantages. Chlorella vulgaris grows quickly throughout the year and can be produced using relatively little land and freshwater compared with many conventional crops. It is also naturally rich in protein.
However, adding algae to ketchup creates an obvious problem: taste.
Microalgae can have a distinctive flavor that may work well in some foods but could easily overpower ketchup. Previous research, for example, has used algal proteins in plant-based seafood products, where their slightly fishy taste can actually be helpful.
To overcome this problem, the researchers extracted protein from C. vulgaris and created different ketchup recipes containing between 1% and 13% algal protein. The ketchup also contained traditional ingredients including plum tomatoes, sugar, vinegar, salt, spices and citric acid. A regular ketchup without algae was prepared for comparison.
After the products were bottled and pasteurized, a panel of 15 people evaluated their taste and appearance.
The most successful versions contained relatively small amounts of algae. Ketchup with 1% or 3% added algal protein maintained the familiar sweet, tangy and mildly spicy flavor people expect from ketchup. Tasters noticed only a slight algal flavor.
Adding larger amounts caused problems. At concentrations of 5% and 13%, the algae produced a stronger taste and gave the ketchup a more noticeable greenish color. These changes made the products less appealing to the taste testers.
Still, the nutritional improvements were significant. Compared with regular ketchup, versions containing 3% and 5% algal extract provided about two to three times as much protein. They also contained more essential amino acids, minerals such as iron and sodium, and antioxidants.
The findings suggest that adding a moderate amount of algal protein could improve ketchup’s nutritional value without dramatically changing the qualities consumers enjoy.
More research is needed before algae-enriched ketchup reaches supermarket shelves. The researchers plan to conduct larger consumer studies, investigate how well the product keeps during storage and explore whether it can be produced successfully on a commercial scale.
