Fermenting seaweed could boost consumption

Fermented seaweed? Those who have tried it think it is much tastier than it sounds, and researchers at Lund University in Sweden are now hoping that acidified seaweed, rather than today’s dried version, will signify a major breakthrough for seaweed as a food source.

Biotechnology researchers have been experimenting with treating fresh seaweed with lactic acid bacteria (fermenting it). But why? Well, the dried seaweed sold as food today is often perceived as having a slightly too “fishy” flavor. With fermentation, the flavor becomes milder without sacrificing the characteristic umami taste.

Two further advantages of fermenting seaweed are that it avoids an energy-intensive drying process and that the lactic acid bacteria that grow during fermentation have been shown to reduce any harmful heavy metals.

In other words, it is tastier, healthier and more environmentally friendly.

Could clean the Baltic Sea

Whatever the cooking method, seaweed is both healthy and potentially good for the environment. Healthy because it contains a rich source of precious nutrients. Environmentally friendly because there are large cultivation areas available at sea that do not take up land space.

“Seaweed could help clean the Baltic Sea and other oceans, as it utilizes carbon dioxide present in seawater. It also absorbs nitrogen and phosphorus and therefore needs no fertilizer or watering for that matter,” says Eva Nordberg Karlsson, professor of biotechnology at Lund University and research team leader.

Stimulating growth of beneficial gut bacteria

The lab in Lund has a lab copy of our intestines, known as an intestinal simulator. Food is left there for between 24 and 70 hours, which is the time it takes for food to pass through the digestive system.

The same brown seaweed used in fermentation has been passed through the intestinal simulator. The analysis of the “feces” shows that both fermented and unfermented seaweed stimulates the growth of beneficial gut bacteria. In addition, healthy short-chain fatty acids are released.

Fermentation helps to preserve the seaweed by lowering the pH value to below 4.3, which prevents the growth of unwanted bacteria.

Savoring the flavor

The flavor was also evaluated by a panel of 20 people. All of them gave fermented seaweed a higher rating compared with dried or fresh seaweed. To further enhance the flavor experience, the fermented seaweed was mixed with an African fruit—baobab—imported by a Lund-based start-up company. This blend was highly appreciated and rated very highly by the tasting panel.

“If everything goes according to plan, you will be able to buy seaweed/baobab spread in the shops in a few years,” says Nordberg Karlsson.

Removing heavy metals

Another challenge facing seaweed as a food source is to ensure that it does not contain heavy metals (cadmium, lead, mercury and arsenic) or iodine in quantities that could pose a health risk.

“Our studies show that the lactic acid bacteria actually reduced these substances so that the seaweed meets the requirements of the Swedish Food Agency,” says Nordberg Karlsson.

Long launch phase

Seaweed is well established as a staple food source in Asia, but has only become popular in Europe in recent years. According to Nordberg Karlsson, research in this area is now increasing significantly.

“It’s been a long launch phase, but we are beginning to understand more and more. A lot has happened in the last three or four years, not only in terms of using whole seaweed but also isolating different components to increase its utilization.

There are a few other research teams in the world working on fermented seaweed, but so far there are very few products on the market, so there is still a lot to do,” says Nordberg Karlsson.