Omega-3 fatty acid and B12 vitamin content in Baltic algae

Abstract

Seaweeds have been gaining popularity in the Western world due to increased interest in alternative food sources and improving the nutritional profile and functionality of food products. This paper analyzed the omega-3 fatty acids such as eicosapentaenoic acid (EPA) and α-linoleic acid (ALA) and B12 vitamin content in the most common Baltic seaweeds. These nutrients have an important part in the human diet. Five seaweeds species (Fucus vesiculosus, Furcellaria lumbricalis, Cladophora glomerata, Pilayella littoralis and Ulva intestinalis) were sampled during April–May, June–July, and August–September. The fatty acids were determined by GC–MS whereas B12 content was analyzed by HPLC-UV. 16S rRNA amplification from community DNA and sequencing was carried out to evaluate B12 synthesizing microorganisms associated with the studied seaweeds. The results showed that F. vesiculosus (5.19 ± 0.32 mg/gDW) was the best source of EPA, followed by F. lumbricalis, C. glomerata, P. littoralis and U. intestinalis irresponsibly of sampling time. The ALA content had little variability between species (1.07–2.45 mg/ g DW). The B12 concentration varied across seasons, being generally lowest during the June–July period. The highest concentration of B12 across all three seasons was in C. glomerata samples (53.55 ± 9.69 μg/100gDW). The lowest B12 vitamin concentration was in F. vesiculosus (4.14 ± 0.36 μg/100gDW). 16S RNA amplicon analysis revealed a correlation between Cyanobacteria and EPA, while no correlation could be found between B12 neither on phyla nor family levels. B12 content in the samples was in correlation with 5 potentially B12 synthesizing bacteria species (Rhodobacter capsulatus, Rhodobacter sphaeroides, Pseudomonas putida, Xanthomonas oligotrophicus and Aeromonas hydrophila) although the abundance of corresponding OTUs did not exceed 1 %.