As grey colour of millet may not be very appealing, researchers tried removing the pigment and see if past made from depigmented millet is still healthy. It was found that removing the pigment improved the colour of pasta and it looked almost like wheat pasta.
In the study, pigment responsible for the colour of millet was removed by soaking the grains in diluted hydrochloric acid, which is commonly used in food industry. The grey colour is due to polyphenols which are sensitive to low pH. Soaking the grains in acid solution leaches out pigments and improves the colour.
The study also compared millet in its original form and after removing the colour to see if benefits were reduced in any way. Four kinds of pasta were made—wheat, millet grain, depigmented millet grain and wheat-millet combination. The grains were all of the same size and were compared for their nutritional value, cooking qualities, texture and visual appeal.
It was found that the amount of protein, fat and mineral content of pearl millet pasta was higher than that of pasta prepared using wheat only. However, cooking properties and texture were better in wheat pasta than others.
Dipping pearl millet grains in acidic solutions like tamarind pods, vinegar or sour milk decreased the grey colour of the grain faster. However, it also tends to drain out proteins. The heat used during processing tends to breakdown larger proteins into smaller substances.
Though the protein content is higher in grey-coloured natural millet, depigmented millet is also nutritious because certain anti-nutrients (substances that interfere with the body’s ability to digest proteins and reduce the availability of minerals and carbohydrates) get removed during soaking and processing of natural millet.
Cooking and texture properties such as hardness, sticking together, springiness and chewiness of pasta were not affected by removing the colour. The colour of pasta after removal of the pigment was as good as pasta made using refined flour.
The study has been done by Kirti Jalgaonkar and Manoj Kumar Mahawar from the Central Institute of Post-Harvest Engineering and Technology, Abohar; and S. K. Jha (Indian Agricultural Research Institute, New Delhi).