The nutritional value of millets

Source: The post is based on the article “The nutritional value of millets” published in The Hindu on 15^th May 2023.

Syllabus: GS 3 – Agriculture

Relevance: About Millets

News: The UN Food and Agriculture Organization (FAO) has declared 2023 to be the ‘International Year of Millets’.

What are millets?

Read Here: India’s Wealth: Millet For Health – Explained

In 2021-2022, India accounted for 40.51% of the world’s pearl millet production and 8.09% of sorghum.

Why are millets preferred?

Read Here: Millet Production in India – Explained

What are the types of nutrition present in the millets?

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Foxtail millet is rich in the amino acid lysine; finger millet has more crude fibre than wheat and rice; proso millet has a significant amount of the amino acids’ leucine, isoleucine, and methionine.

Where are these nutrients stored?

Each millet kernel consists of three major parts, called pericarp, endosperm, and germ.

The pericarp has an outer covering called the husk. The husk and pericarp together protect the kernel from bad weather, disease, and physical injury.

The endosperm is the largest part of the kernel and its storage centre. It has a protein covering called aleurone.

The endosperm is relatively poor in mineral matter, ash and oil content but a major contributor to the kernel’s protein (80%), starch (94%) and B-complex vitamins (50-75%).

Similarly, pearl millet has a relatively larger germ, which is rich in oil (32%), protein (19%) and ash (10.4%), with over 72% of the total mineral matter.

How does processing affect the nutrients?

Processing and preparing millets for consumption can affect nutrients in three ways — enhance them, suppress/remove them, and ignore them.

Removing the Husk: The husk is removed from the grains because it is composed of cellulosic matter that the human body cannot digest. However, according to one study when husk was removed from pearl millets, their phytic acid and polyphenol contents dropped.

Decorticating the grain: Decorticating refers to removal of any other outer covering which exposes the seed. Studies have found mechanical and hand-worked decortication removed crude and dietary fibre from the grain.

However, decortication makes the grain more edible and visually attractive.

Milling and Sieving: While milling grind the grains into flour, sieving removes large impurities, including bran. Studies have found the longer the grains were milled, the more protein, fat, and fibre contents were removed.

Sieving made the flour more digestible and its nutrients more accessible to the body. However, it also reduced nutrient content due to the loss of bran.

Germination and fermentation: These refer to soaking grains in water for an extended duration. It showed a positive improvement in the overall nutritional characteristics of millets.

Polishing: Polishing is the process of transforming brown rice into white rice by rubbing off the bran and germ. Studies have found that polishing removed 8-10% of grain weight and also removed 60-80% of iron, magnesium, phosphorus, potassium, and manganese.

However, rice polishing is considered desirable because most consumers favour the resulting taste and texture and prefer the shorter cooking time while it benefits retailers with longer shelf-life.