Question

People recovering from long illnesses are often advised to include the algae Spirulina in their diet because
(a) Makes the food easy to digest
(b) Is rich in proteins
(c) Has antibiotic proteins
(d) Restores intestinal microflora

Answer 1

Hint: Spirulina algae is a nutrient-rich food that is available as supplements for human consumption. They contain certain compounds that are useful for the body. It is also easy to grow and process into edible products.

Complete answer:
- Spirulina is microscopic and filamentous cyanobacteria or blue-green algae consisting of different species, such as Spirulina maxima and Spirulina platensis.

- The algae is a highly rich source of protein and the percentage of protein dry weight ranges from $30\%$ to $70\%$. This is also a source of protein that can be consumed by non-meat eaters.
- Other nutrients that are present in significant quantities include lipids, pigments like carotenoids, iron, and vitamins. They are also known to contain all the amino acids.

Additional information:
- Spirulina grows in both fresh and saltwater. They are structurally multicellular cylindrical filaments arranged in an open left-handed helix.
- The pigment that gives the algae the blue-green color is phycocyanin, which is also an antioxidant and an anti-inflammatory agent.
- The algae can be manufactured in controlled conditions in outdoor pond systems.
- Other algal species with high levels of proteins include Chlorella, Nostoc, and Scenedesmus.
- Apart from phycocyanin, they also contain chlorophyll a and carotenoids.
So, the correct answer is ‘(b) Is rich in proteins’.

Note:
- The Spirulina species are also known as Arthrospira.
- Spirulina is known to grow in alkaline environments and can also be found in soils and marshes.
- Spirulina does not contain vitamin ${ B }_{ 12 }$ but pseudovitamin ${ B }_{ 12 }$ which is not utilized by the human body.