Modern Processing of Indian Millets: A Perspective on Changes in Nutritional Properties

Abstract

Globally, billions of people are experiencing food insecurity and malnutrition. The United Nations has set a global target to end hunger by 2030, but we are far from reaching it. Over the decade, climate change, population growth and economic slowdown have impacted food security. Many countries are facing the challenge of both undernutrition and over nutrition. Thus, there is a need to transform the food system to achieve food and nutrition security. One of the ways to reach closer to our goal is to provide an affordable healthy and nutritious diet to all. Millets, the nutri-cereals, have the potential to play a crucial role in the fight against food insecurity and malnutrition. Nutri-cereals are an abundant source of essential macro- and micronutrients, carbohydrates, protein, dietary fiber, lipids, and phytochemicals. The nutrient content and digestibility of millets are significantly influenced by the processing techniques. This review article highlights the nutritional characteristics and processing of Indian millets, viz. foxtail, kodo, proso, little, and pearl millets. It also envisages the effect of traditional and modern processing techniques on millet’s nutritional properties. An extensive literature review was conducted using the research and review articles related to processing techniques of millets such as fermentation, germination, dehulling, extrusion, cooking, puffing, popping, malting, milling, etc. Germination and fermentation showed a positive improvement in the overall nutritional characteristics of millets, whereas excessive dehulling, polishing, and milling resulted in reduction of the dietary fiber and micronutrients. Understanding the changes happening in the nutrient value of millets due to processing can help the food industry, researchers, and consumers select a suitable processing technique to optimize the nutrient value, increase the bioavailability of nutrients, and help combat food and nutrition security.

Influence of processing techniques on the protein quality of major and minor millet crops: A review

“…This might be due to the elimination of bran from the endosperm, thus reducing phytate and tannin content and binding the protein complex, thereby improving protein content and digestibility (Devisetti et al, 2014). Decortication and dehulling of pearl millet significantly impacted the protein, which increased up to 17.5% with increased functionality and digestibility; however, beyond the dehulling point, the protein content decreased (Nanje Gowda et al, 2022). The hulled millet with decortication led to the elimination of the anti-nutrients and polyphenolic compounds, causing improved protein concentration and digestibility.…”

“…The different processing treatments such as hydrothermal, soaking, fermentation, and extrusion were performed on browntop millet, and the results exhibited that the protein content increased by 17.31 ± 0.25% in the untreated sample followed by dry heating (14.56 ± 0.29%), hydrothermal treatment (14.23 ± 0.18%), fermentation (13.40 ± 0.84), soaking (12.72 ± 0.90%), and extrusion(10.77 ± 0.11%;Santhi Sirisha et al, 2022). The parting granules of starch with protein molecules and reduction in anti-nutritional compounds such as trypsin and phytate acid were observed during the thermal treatment of millet crops (NanjeGowda et al, 2022).…”

“…A study found that the temperature used to process millet affects the anti-inflammatory action of millet peptides (Jakubczyk et al, 2019). Besides, during the thermal treatment of millet crops, it was observed that there is a reduction in anti-nutritional properties such as trypsin and phytate acid (Nanje Gowda et al, 2022). Temperature regulation during heat treatment can lessen the undesirable effects of the digestion step on millet peptides (Karaś et al, 2019).…”

Impact of cold plasma treatment on nutritional, antinutritional, functional, thermal, rheological, and structural properties of pearl millet flour

“…Pearl millet ( Pennisetum glaucum ), an underutilized crop, belongs to the Poaceae family and is a major staple food worldwide, and India contributes ~39% of worldwide Millet production with an average production rate of 12 MT in 2022 (pearl millet: ~8.61 MT in 2020–2021) followed by Niger, China, and Nigeria (FAO, 2022; Sanjana Reddy et al, 2021). It comprises carbohydrates (67.5%–76%), protein (13.4%–18.6%), fat (5.6%–7.8%), basically polyunsaturated, and low level of cholesterol, crude fiber (1.3%–2.8%), vitamins B (B 2 , B 1 , and B 6 ), and rich sources of minerals (calcium, magnesium, phosphorus, potassium, and sodium) (Adepehin, 2020; Gowda et al, 2022). Apart from this, pearl millet protein had higher threonine (30%), methionine (40%), and lysine content than corn protein.…”

Nutrients Anti-Nutrients Interaction in Millets and its Effect on Malnutrition

“…In finger millet, besides nutrients it also contains oxalate, phytate, polyphenols, tannins, dietary fiber and trypsin inhibitory factors, these were called as ' Anti-nutrients' for their metal chelating and enzyme inhibition activities [7]. According to earlier studies the presence of nutrient like calcium in plants exists primarily as a complex form in which it is bound with anti-nutrients such as phytate, oxalate [38,39] along with proteins and other nutrient factors. Legumes and cereals also contains anti-nutritional factors like phytic acid, saponins, tannins, gossypol, lectins, protease inhibitors, amylase inhibitor, and goitrogens [40].…”