Millets are ancient cereal crops that have traditionally contributed to human diets in Asia and Africa. In recent years, their importance has increased because of growing interest in climate-resilient crops, dietary diversification, gluten-free foods, and plant-based nutrition. Unlike several major cereals, millets can often be cultivated under relatively low-input conditions and are adapted to environments characterized by limited water availability [1]. Millets contain carbohydrates, proteins, dietary fibre, minerals, vitamins, phenolic compounds, and other phytochemicals. Finger millet is particularly recognized for its calcium content, while pearl millet provides substantial amounts of protein, iron, zinc, and other minerals. Several small millets also contain phenolic compounds and dietary fibre that contribute to their functional potential [2].

The development of millet milk provides an opportunity to transform these cereals into a convenient liquid food. Similar to other plant-based beverages, millet milk may serve as a dairy alternative for consumers seeking plant-based products. It can also function as a carrier for additional nutrients, probiotics, fruit ingredients, or other functional components.

2. Nutritional Composition of Millet Milk

The nutritional profile of millet milk depends strongly on the millet species, grain-to-water ratio, processing conditions, filtration, and subsequent fortification. Carbohydrates generally constitute the major macronutrient fraction, while protein and lipid contents vary according to the raw material and formulation. Processing may alter fibre distribution and the availability of minerals and phytochemicals. Millets contain phenolic acids, flavonoids, tannins, and other compounds that contribute to antioxidant capacity. Processing such as germination and fermentation can modify these compounds and potentially improve their bio-accessibility [3].

Millet milk may therefore contribute to dietary fibre and micronutrient intake, although its nutritional value should not automatically be considered equivalent to that of cow’s milk. Calcium, vitamin B12, vitamin D, and protein quality may require targeted fortification depending on the intended nutritional profile.

3. Processing Technologies

3.1 Grain Preparation and Soaking

The first stage generally involves cleaning and washing the grains, followed by soaking. Soaking softens the grain structure and facilitates subsequent wet milling. It can also reduce selected antinutritional factors and improve the extraction of soluble components.

3.2 Germination

Germination is increasingly investigated as a pretreatment for millet-based beverages. During germination, endogenous enzymes become active and modify starch, proteins, and other components. Germination can potentially improve digestibility, reduce certain antinutritional compounds, and alter the concentration or availability of phenolic constituents [4]. However, germination must be carefully controlled because excessive sprouting can affect flavour, microbial stability, and processing characteristics.

3.3 Wet Milling and Filtration

After hydration, millet grains can be wet-milled with water to produce a slurry. Filtration or centrifugation removes coarse particles and produces a smoother beverage. The degree of filtration affects the final fibre content, viscosity, mouthfeel, and sedimentation behaviour. The incorporation of finely processed whole-grain fractions may increase nutritional value but can also increase sedimentation and reduce physical stability. Consequently, particle-size control is important for beverage quality.

3.4 Enzymatic Treatment and Homogenization

Enzymes such as amylases can modify starch and reduce excessive viscosity. Enzymatic hydrolysis can also influence sweetness and beverage consistency. Homogenization reduces particle size and helps maintain a more uniform dispersion of components. Hydrocolloids or other stabilizing systems may be used to reduce sedimentation, although their concentration must be optimized to avoid undesirable texture.

3.5 Thermal Processing and Fermentation

Pasteurization or other suitable thermal treatments are necessary to improve microbiological safety and shelf stability. Excessive heating, however, may affect flavour and heat-sensitive compounds. Fermentation with selected lactic acid bacteria provides another promising approach. Fermentation may improve digestibility, modify flavour, reduce certain antinutritional compounds, and generate potentially beneficial metabolites [5]. Fermented millet beverages may therefore provide an attractive combination of cereal nutrition and probiotic functionality.

4. Value-Added Products

Millet milk can serve as a base for several value-added products. It may be formulated with fruits, cocoa, spices, nuts, or other plant ingredients to improve flavour and nutritional diversity. Fortification with calcium, vitamin D, vitamin B12, or plant proteins can also be considered depending on the target consumer group. Fermented millet milk can be developed into yoghurt-like products with suitable starter cultures. Such products may provide a dairy-free alternative with improved sensory characteristics and potential probiotic benefits. Millet milk can also be incorporated into bakery formulations, puddings, desserts, smoothies, breakfast cereals, and frozen products. Millet-based beverages may be particularly useful in products targeting consumers interested in gluten-free and plant-based diets.

5. Functional Potential

The functional properties of millet milk are largely related to the nutrients and phytochemicals derived from the whole grain. Dietary fibre may support gastrointestinal health and contribute to favourable glucose and lipid metabolism. Phenolic compounds possess antioxidant activity and may interact with pathways associated with oxidative stress and inflammation [6]. Millet-based foods have also attracted interest in relation to glycaemic management. The presence of dietary fibre, resistant starch, slowly digestible carbohydrates, and phenolic compounds may contribute to a lower postprandial glycaemic response compared with some highly refined cereal products. However, the actual effect depends on millet type, processing conditions, formulation, and serving size. Fermentation may further modify the functional characteristics of millet beverages. Microbial metabolism can transform phenolic compounds and carbohydrates while producing organic acids and other metabolites. Consequently, fermented millet products represent an important area for future functional food research.

6. Challenges and Future Perspectives

Despite its potential, millet milk faces several technological and commercial challenges. Raw millet can produce undesirable cereal flavours, bitterness, or astringency, partly because of phenolic compounds and other constituents. Sedimentation and phase separation may also occur during storage. Another challenge is nutritional standardization. Unlike dairy milk, naturally produced millet milk may contain relatively low levels of certain micronutrients, particularly calcium and vitamin B12. Appropriate fortification may therefore be necessary for products intended as nutritional substitutes. Future research should focus on optimizing germination, enzymatic treatment, homogenization, fermentation, and stabilization techniques. Sensory studies involving diverse consumer groups are also required to identify acceptable flavour and texture profiles. The combination of millet milk with probiotics, prebiotics, fruit extracts, plant proteins, or bioactive compounds may create new generations of multifunctional beverages. Sustainable processing and utilization of millet residues could further enhance the environmental and economic value of the production system.

7. Conclusion

Millet milk represents a promising plant-based beverage with potential nutritional, technological, and functional applications. Its development provides an opportunity to utilize nutrient-rich and climate-resilient millets in convenient modern foods. Soaking, germination, wet milling, enzymatic treatment, homogenization, thermal processing, and fermentation can be combined to improve beverage quality and functionality. Millet milk can also serve as a foundation for fermented drinks, yoghurt alternatives, smoothies, desserts, and fortified products. Nevertheless, improvements in flavour, physical stability, nutritional standardization, shelf life, and consumer acceptance remain necessary. Future research integrating food processing, fermentation, nutrition, and sustainable production could establish millet milk as an important component of the expanding functional and plant-based food sector.

References

[1] Saleh, A. S. M., Zhang, Q., Chen, J., & Shen, Q. (2013). Millet grains: Nutritional quality, processing, and potential health benefits. Comprehensive Reviews in Food Science and Food Safety, 12(3), 281–295.

[2] Amadou, I., Gounga, M. E., & Le, G. W. (2013). Millets: Nutritional composition, some health benefits and processing—A review. Emirates Journal of Food and Agriculture, 25(7), 501–508.

[3] Chandrasekara, A., & Shahidi, F. (2012). Bioaccessibility and antioxidant potential of millet grain phenolics as affected by simulated in vitro digestion and microbial fermentation. Journal of Functional Foods, 4(1), 226–237.

[4] Nkhata, S. G., Ayua, E., Kamau, E. H., & Shingiro, J. B. (2018). Fermentation and germination improve nutritional value of cereals and legumes through activation of endogenous enzymes. Food Science & Nutrition, 6(8), 2446–2458.

[5] Blandino, A., Al-Aseeri, M. E., Pandiella, S. S., Cantero, D., & Webb, C. (2003). Cereal-based fermented foods and beverages. Food Research International, 36(6), 527–543.

[6] Taylor, J. R. N., & Duodu, K. G. (2015). Effects of processing sorghum and millets on their phenolic phytochemicals and the implications for health. Molecules, 20(1), 1041–1062.

[7] Saleh, A. S. M., Wang, P., Wang, N., Yang, S., & Xiao, Z. (2019). Brown rice versus white rice: Nutritional quality, potential health benefits, development of food products, and preservation technologies. Comprehensive Reviews in Food Science and Food Safety, 18(4), 1070–1095.

[8] Jeske, S., Zannini, E., & Arendt, E. K. (2018). Past, present and future: The strength of plant-based dairy substitutes based on gluten-free raw materials. Food Research International, 110, 42–51.

[9] Sethi, S., Tyagi, S. K., & Anurag, R. K. (2016). Plant-based milk alternatives: An emerging segment of functional beverages: A review. Journal of Food Science and Technology, 53, 3408–3423.