Microwave-Assisted Parboiling: Enhancing Milling Quality and Nutritional Profile of Kodo Millet

Abstract

Kodo millet, a minor millet known for its high nutritional value and remarkable drought resilience, faces processing challenges due to its thick hull layers. Hydrothermal pretreatment before milling has been shown to reduce grain fragility and milling loss. Traditional parboiling methods, however, are both energy and time-intensive. This study proposes a novel parboiling approach using microwave irradiation to evaluate its effects on the milling and grain quality of Kodo millet during the soaking and gelatinization stages. The millet was soaked at three microwave power levels, 90, 270, and 450 W, for 60, 30, and 20 min, respectively, to achieve a moisture content of 30% ± 2%. Gelatinization was done at 270 W for 20 min. Milling characteristics such as head grain yield, broken, and dehulling efficiency, grain dimensions, color, cooking time, and nutritional profile were evaluated. Microwave treatment significantly reduces processing time while enhancing the hardness and milling quality of the grain when compared to conventional parboiling methods. An increase in head grain yield and a reduction in the broken percent and cooking time and lighter color grains were observed, suggesting that microwave irradiation may be more advantageous than conventional parboiling. The nutritional profile of parboiled millet was also improved by MP as it preserved more protein and ash than the conventional approach. The findings suggest that microwave-assisted parboiling can serve as an effective, time-efficient method to enhance the milling and grain quality of Kodo millet, promoting its utilization as a functional food in modern diets.