Comparative production and nutritional value\ud of "sea grapes" — the tropical green seaweeds Caulerpa\ud lentillifera and C. racemosa

"Sea grapes" is a collective term for the edible varieties of the green seaweed genus Caulerpa. Here we conduct comparative analyses of the biomass productivities and biochemical properties of C. lentillifera and C. racemosa from tropical Australia. Commercial-scale production was evaluated using 1 m2 culture units with high stocking densities (>5 kg m−2). Productivity of C. lentillifera in a 6-week period yielded, on average, 2 kg week−1, whereas C. racemosa yielded <0.5 kg week−1. Morphometric comparisons of the harvestable biomass revealed that C. lentillifera had a higher proportion of fronds (edible portions) to horizontal runners (stolons) and a higher density of fronds per unit area. C. racemosa fronds, however, were significantly longer. The nutritional value of C. racemosa was higher than C. lentillifera for both polyunsaturated fatty acids (10.6 vs. 5.3 mg g−1 DW) and pigments (9.4 vs. 4.2 mg g−1 DW). The content of eicosapentaenoic acid (EPA) and β-carotene decreased with increasing frond size in both species. Trace element contents also varied substantially between the species, including higher levels of zinc, magnesium and strontium in C. lentillifera, and higher levels of selenium in C. racemosa. Some less desirable elements were higher in C. lentillifera, including arsenic (1 vs. 0.1 ppm) and cadmium, whereas others were higher in C. racemosa, including lead, copper and vanadium. Overall C. lentillifera has a high biomass production potential in monoculture and distinct nutritional properties that warrant a focus on its commercialisation as a new aquaculture product in tropical Australia and in Southeast Asia more broadly

Bioactive compounds in seaweed; functional food applications and legislation

Seaweed is more than the wrap that keeps rice together in sushi. Seaweed biomass is already used for a wide range of other products in food, including stabilising agents. Biorefineries with seaweed as feedstock are attracting worldwide interest and include low-volume, high value-added products and vice versa. Scientific research on bioactive compounds in seaweed usually takes place on just a few species and compounds. This paper reviews worldwide research on bioactive compounds, mainly of nine genera or species of seaweed, which are also available in European temperate Atlantic waters, i.e. Laminaria sp., Fucus sp., Ascophyllum nodosum, Chondrus crispus, Porphyra sp., Ulva sp., Sargassum sp., Gracilaria sp. and Palmaria palmata. In addition, Undaria pinnatifida is included in this review as this is globally one of the most commonly produced, investigated and available species. Fewer examples of other species abundant worldwide have also been included. This review will supply fundamental information for biorefineries in Atlantic Europe using seaweed as feedstock. Preliminary selection of one or several candidate seaweed species will be possible based on the summary tables and previous research described in this review. This applies either to the choice of high value-added bioactive products to be exploited in an available species or to the choice of seaweed species when a bioactive compound is desired. Data are presented in tables with species, effect and test organism (if present) with examples of uses to enhance comparisons. In addition, scientific experiments performed on seaweed used as animal feed are presented, and EU, US and Japanese legislation on functional foods is reviewed