Researchers at Sweden's Lund University explore fermentation to improve seaweed's flavor, health benefits, and environmental impact

Seaweed has long been recognized as a nutritious and environmentally friendly food source, but researchers at Lund University in Sweden believe fermenting seaweed could significantly increase its appeal. By treating fresh seaweed with lactic acid bacteria, they have found ways to make it tastier, healthier, and more sustainable than the dried version typically sold today.

The dried seaweed available on the market often carries a strong 'fishy' flavor that some find off-putting. Fermentation, however, mellows the flavor while preserving the umami taste that makes seaweed distinct. According to tasting panels, fermented seaweed scored significantly higher than both dried and fresh versions. To further enhance its appeal, researchers combined fermented seaweed with baobab, a tangy African fruit, creating a spread that received rave reviews.

Beyond its improved taste, fermentation offers key environmental and health benefits. Unlike traditional seaweed drying methods, which are energy-intensive, fermentation is a low-energy process. The lactic acid bacteria involved in fermentation also reduce harmful heavy metals, such as cadmium and mercury, making the seaweed safer to consume.

Professor Eva Nordberg Karlsson, who leads the research team at Lund, highlights seaweed's environmental advantages. “Seaweed could help clean the Baltic Sea and other oceans, as it utilizes carbon dioxide in seawater and absorbs nitrogen and phosphorus. It doesn’t need fertilizer or watering.”

Seaweed’s cultivation potential is also immense, as it can be grown in large ocean areas without taking up valuable land space. By consuming nutrients from seawater, seaweed contributes to marine health while producing a highly nutritious food source rich in vitamins and minerals.

The research team used an intestinal simulator to replicate how seaweed interacts with the human digestive system. Both fermented and unfermented seaweed were found to stimulate the growth of beneficial gut bacteria and release short-chain fatty acids, which are known to support gut health. Additionally, fermentation helps preserve seaweed by lowering its pH to below 4.3, preventing the growth of harmful bacteria.

One barrier to seaweed’s widespread adoption as a food source in Europe has been concerns about heavy metal content. Seaweed can sometimes contain cadmium, lead, mercury, or arsenic, as well as iodine levels that exceed safe limits. However, the researchers discovered that fermentation with lactic acid bacteria significantly reduces these harmful substances, ensuring the seaweed meets Swedish Food Agency requirements.

While seaweed is a staple food in Asia, it is still gaining traction in Europe. According to Professor Nordberg Karlsson, research into seaweed as a food source has grown substantially in recent years. “It’s been a long launch phase, but we’re beginning to understand more and more. There is still much to do, but the progress in the last three or four years has been remarkable.”

Though fermented seaweed products are not yet widely available, the Lund University team is optimistic about its commercial potential. If development continues as planned, consumers could see products like seaweed and baobab spreads on store shelves within a few years.