Strategic Review on Parboiling of Millets: A Promising Solution to Enhance Millet Processing, Storage Stability and Food Sustainability

A major disadvantage associated with millet processing is the inability to separate the closely attached seed coat and soft endosperm, causing less decortication. Certain pre‐treatments, such as parboiling (soaking and subsequent hydrothermal treatment), can increase grain hardness and imbibe soluble nutrients into the grain endosperm. Parboiling at atmospheric pressure or at elevated pressure has been applied to various millets and published. Lacking a comprehensive review of various pretreatments given before milling and storage, and the impact of these techniques on physical, milling, functional, and storage characteristics of various millets to enhance their stability and application identifies major gaps in the research and application. The present review has been designed to elaborate on those characteristics that are the outcome of recent research on millet processing and utilization. The findings covered reveal that soaking followed by parboiling by soak‐boil and soak‐steam methods not only improve physical, milling (de‐husking, decortication) yield characteristics, bio‐accessibility, antioxidant property, storage stability and physicochemical characteristics of either whole, de‐husked, decorticated grain or flour but also can effectively prolong storage stability and flour functional characteristics such as lipid stability (% FFA, PO‐value), improving flour water holding and absorption, solubility, and sedimentation indices. The review also covers the impact of hydrothermal processing on grain macromolecules' digestibility and bioavailability. Parboiling and effective decortication can enhance the millet grains/flour diversification opportunities and stabilize grain and oxidative storage stability. Overall integration of parboiling into millet processing offers a promising solution to enhance the economic viability of millet, milled millet, and millet‐based products.