Effect of Hydrothermal Treatment on Physical, Nutritional and Functional Properties of Pearl Millet (Pennisetum glaucum) Flakes

Pearl millet flakes were developed using various hydrothermal treatments to assess their impact on physical properties, nutritional composition, functional attributes and textural characteristics.

Different hydrothermal treatments, including soaking (at varying temperatures and durations) and steaming or pressure cooking, were applied before flaking. Physical properties like bulk density, color and texture were measured. Functional attributes such as water absorption, fat absorption, emulsion activity and stability were analysed. Nutritional composition, including protein, fat, fiber, minerals and phenolic content, was evaluated.

Hydrothermal treatment T4 (soaking at 65°C for 30 min, followed by steaming for 20 min) produced flakes with the lowest bulk density (355 kg/m³). Higher soaking temperatures and extended steaming times reduced lightness, while shorter durations preserved color. Water absorption index ranged from 2.20-4.10 and fat absorption capacity decreased with increasing bulk density. Nutritionally, flakes contained high energy (410-424 kcal), protein (9.41-12.89 g), fiber (4.01-6.54 g), iron (1.22-1.70 mg), calcium (25.9-34.9 mg) and phosphorus (138-305 mg) per 100 g. Pressure cooking resulted in the highest loss of phenolic content (1.59-0.59 mg GAE/ml), whereas steaming helped retain nutrients better.