Danish brown algae could prolong shelf life and improve taste
The brown algae was found to contain antioxidants which inhibited lipid oxidation of fatty acids. Oxidisation causes the acids to fester and can mean an unpleasant taste or smell in products.
The study looked at food products fortified with omega-3 rich fish oils, though baldderwrack has wider applications across other fats prone to oxidation, Ditte Baun Hermund wrote in her PhD thesis at the National Food Institute, Technical University of Denmark.
“Lipid oxidation is one of the major contributors to the quality deterioration and loss of functional fatty acids. Antioxidant strategies can be used to increase the oxidative stability of these products prone to lipid oxidation,” Hermund said.
However, more research is needed into antioxidant structure and mode of action before bladderwrack seaweed is ready for commercial use, for instance into any potential adverse effects.
Industrial scale extraction methods also need to be developed.
In a press statement, the National Food Institute said a “foreign company” has already shown interest in extracting antioxidants from bladderwrack and is in preliminary talks with the institute over potential future partnership.
Hermund has so far collaborated with Icelandic government-owned independent research company Matís on this PhD project.
The aim of the study was to extract and characterise highly antioxidative polyphenolic secondary metabolites – phlorotannins – from the Nordic brown alga, also known as Fucus vesiculosus.
Various extracts were made from water, acetone, and ethanol, as well as a fraction of purified phlorotannins, and tested on fish-oil enriched foods. Foods studied included milk, granola bars and mayonnaise.
Fish oil was chosen because it is prone to becoming rancid, Hermund explained.
“The effectiveness of these extracts was to a large degree dependant on their antioxidant properties and composition, which in turn depended on the extraction medium used,” she said.
“In general, water was efficient in extracting iron chelating compounds.”
The high iron chelating ability of the water extract was particularly effective in enriched mayonnaise, she added.
Lipid oxidation has been a major problem for quality preservation in products containing fatty acids.
In particular, it has been an issue for long chain polyunsaturated fatty acids (PUFAs). The process can lead to offensive taste, loss of nutrients and even dangerous toxic compound formation.
Synthetic antioxidants are widely utilised in the food industry to counteract the issue, though these come with restrictions because they too carry health risks and toxicity, Hermund said.
“Hence there is a significant interest in and demand for replacing synthetic antioxidants with natural plant-based alternatives, not only due to safety issues but also due to a generic interest in sustainable and natural solutions,” she added.
Marine algae are a hugely underutilised resource in the Nordic region and their use is limited largely to inexpensive, low-grade products, she added.
If commercial-scale application is proven this could be the perfect solution.
“Out of an estimated many millions of metric tons of seaweed biomass in Iceland (alone), less than 20,000 tons of marine seaweed are harvested, representing a minute fraction of what could be harvested and utilized. The Nordic countries are in a unique position to create significant value from their very abundant seaweed resources,” she added.
However, cultivation needs to be given some thought since bladderwrack’s optimal growth conditions are costly onshore cultivation. It is largely unsuitable for the less expensive open water offshore cultivation, Hermund added.
“It is possible though to create the right conditions on the seabed at intertidal, sheltered place with relatively high salinity for wild population of F. vesiculosus to settle and grow to be harvested and utilized for production of high quality seaweed based products,” Hermund noted.
Other potential applications of bladderwrack include weight loss supplements since it has been found to have some fat-blocking properties, another study suggests.
Source: National Food Institute Technical University of Denmark
“Extraction, characterization and application of antioxidants from the Nordic brown alga Fucus vesiculosus”
Author: Ditte Baun Hermund