12 January - 20 June 2016

The potential of seaweed in the development of functional foods and nutraceuticals

Seaweeds are a valuable source of bioactive compounds, which could be used in the development of functional foods and nutraceuticals according to a review published in Trends in Food Science and Technology. The review discusses the challenges of extraction of these bioactive compounds due to the complex structure of seaweed cell walls.

Seaweeds are a valuable source of bioactive compounds, which could be used in the development of functional foods and nutraceuticals according to a review published in Trends in Food Science and Technology. The review discusses the challenges of extraction of these bioactive compounds due to the complex structure of seaweed cell walls. 

Seaweeds are rich in carbohydrates, proteins, polyunsaturated fatty acids and minerals as well as polyphenols, pigment and mycosporine-like amino acids. The most important product produced from seaweeds are polysaccharides, which account for up to 76% of their dry weight.  The majority of these polysaccharides are thought to act as a prebiotic, as they can be fermented by gut microbiota and stimulate the growth of "beneficial gut bacteria." Beneficial bacteria in the gut can ferment seaweed components so they produce metabolites such as short chain fatty acids which are thought to protect from obesity, asthma, cancer and inflammatory bowel amongst others. Previous studies, have investigated their prebiotic effects on mice and rats.  One study found that a mice diet supplemented with red seaweed increased the abundance of Bifidobacterium breve and led to a decrease of pathogenic bacteria.  Another found that supplementation with brown seaweed suppressed weight gain in rats, and “influenced the composition of gut microbial communities.”

Whilst seaweed has been reported to contain many bioactive compounds, extraction of these is a challenge.  The review discusses the advances, challenges, and future direction in applying enzyme technologies.  Two major enzyme-enhanced processes used are enzyme-assisted extraction and the enzymatic hydrolysis of macromolecules.  Cellulases and proteases cause hydrolysis of the cellulose and protein network, breaking down the cell wall to release bioactive components. Previous research suggests that “enzyme assisted extraction may be a promising technique for the recovery of proteins, neutral sugars, uronic acids and sulphate groups from green, red and brown seaweeds.” However, the review states that there are not many commercial food grade hydrolytic enzymes available at present and that further development of specific polysaccharide hydrolytic enzymes are required.  Whilst carbohydrate hydrolytic enzymes and proteases are available the review indicates that seaweed-specific enzymes are likely to more beneficial in the future. Enzymes are beneficial over “harsh physical and chemical treatments” as they are less likely to cause "excessive structural degradation." Seaweed-specific enzymes have been shown to produce oligosaccharide often with prebiotic properties. 

Once these bioactive extracts have been extracted from the seaweed, the review states that more purification may be required.  Its notes that common techniques for this type of purification include ion-exchange chromatography and size-exclusion chromatography amongst others. 

The review discusses current legislation regarding the use of seaweed in food and functional food supplements.  It notes that "most jurisdictions" have defined the maximum levels of heavy metals allowed in seaweeds and that seaweed can contain high levels of iodine. In Australia, brown seaweed has been added to the imported food "risk list" due to the iodine levels it may contain.  The report states that maximum allowed bacterial levels within dried seaweeds have been defined only in France. 

In conclusion, the authors reiterate that “seaweeds are a valuable source of bioactive compounds especially with regard to their polysaccharides, phenolic compounds and protein.  They state that challenges remain in improving the technique for extraction, and “enzyme intensification using other physical inputs and enzymes with activities specific to seaweed structures, should be further investigated.” 

RSSL's Product and Ingredient Innovation Team, has considerable experience in re-formulating products to provide more healthy options including low salt, low sugar versions and using pre- and probiotics. To find out more please contact Customer Services telephone 0118 918 4076 or e-mail enquiries@rssl.com

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