A leafy future for protein?

Sensemaking / A leafy future for protein?

Can we turn to seaweed, duckweed and algae to fulfil our global protein needs?

By Gillian Phair / 01 Jul 2015

Amidst growing food insecurity, in the context of volatile weather, water shortages, a growing global population and increased meat consumption, there is an emerging trend to develop novel sources of protein to meet global demand. The production of these novel proteins aims to lessen the land, water and resource burden of conventional protein sources.  

The expansion of seaweed cultivation is being considered as one way to meet our protein needs. Although it already a diet staple in much of East Asia, seaweed is starting to appear on gourmet restaurant menus and supermarkets in the western world. Last month, Tesco became the first major supermarket to stock fresh seaweed as a spaghetti product. The brand Mara Seaweed, which is available on Ocado, witnessed a 73% increase in demand in the final quarter of 2014. Laver seaweed is also a traditional dish in Welsh cuisine. 

Not only does seaweed production help to meet human demand for protein, seaweed farms can encourage higher populations of herbivorous marine life. Cultivation of seaweed is a sustainable option if it doesn’t replace other coastal flora such as mangroves and eelgrass, which sequester carbon, filter pollution and protect coastal areas from storms, floods and tsunamis. 

Duckweed is another plant which has been considered as a protein solution.Wolffia, a form of duckweed, is the smallest blossoming plant on earth. It is likened to sweet cabbage in flavour and often eaten in Southeast Asia. Duckweed contains between 20-43% crude protein and its production is highly efficient, as one hectare of duckweed produces the equivalent protein to 10 hectares of soy. Duckweed produces very successful yields very quickly, it is highly nutritious, it produces no waste and is available all year round. Hinoman is an Israel-based producer that is developing duckweed en masse in a highly computerised, remotely controlled hydroponic facility. It hopes to sell inexpensive duckweed as an ingredient for carbohydrate products such as bread, pasta and rice noodles. 

Pollution prevention or retention?

Unlike land-based crops which are often cultivated using excessive amounts of fertiliser, seaweed and duckweed absorb excess nutrients which pollute oceans and ponds, and harm other aquatic life. Therein, they are natural water cleansers. This function makes them ideal for managing fish and animal excretion, purifying water and producing nutritious crop yield for consumption.

However, seaweed and duckweed can also accumulate heavy metals and pesticides, which are deleterious to human health when consumed. Often in Southeast Asia, fertiliser is deliberately flushed into the sea to improve seaweed yields. Caution must be taken to protect against contamination of pathogens, heavy metals and pesticides. To be suitable for human consumption, it needs to be cultivated in clean and soft and nutrient rich water.

Market potential

Both seaweed and duckweed have also been considered as biofuel. Production of these plants as both protein and biofuel sources is beneficial in offsetting the production costs of biofuels. They are also both often used as feed sources – for example, in integrated tilapia and duckweed aquaculture.

But the commercialisation of novel proteins such as duckweed is a long way off, despite media attention and the public intrigue of future food sources. Yet diets are changing: Spirulina (a form of algae) has gained widespread attention as a high protein dietary supplement, with interest growing gradually over time. A challenge is to have these sources recognised and commercialised as direct protein sources for humans around the world.

Image caption: Seaweed pasta?
Image credit: Keith / Flickr 

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