Effect of roasting and heat-moisture treatments on physical properties of proso millet flour (Processing properties of modified proso millet flour, part 1)

Nutrition, in combination with good taste, may be a key for foods to survival in tomorrow's dynamic market. Proso millet has a high nutritional quality but its process characteristics are very poor. The objective of this research was to determine the effect of roasting, microwave and heat-moisture treatments on physical properties of proso millet flour for its application to food. Roasting treatment increased polydispersity of proso millet flour and heat-moisture treatment decreased it. Color of untreated flour resulted in a*, -4.5; b*, 20.1; whiteness, -18. However, whiteness of the flour was increased to the range of 18-43 by any treatments. Roasting and microwave treatments in proportion to temperature and time the decreased the damaged starch content determined by the AACC method, but heat-moisture treatment increased it. All the flour showed A-type of X-ray diffraction patterns. Heat-moisture treatment caused a little reduction of the relative intensities of the peaks. Gelatinization temperatures of treated and non-treated flour were in the range of 73-75degreesC, heat-moisture treatment increased both the conclusion temperature and enthalpy change. Roasting, microwave and heat-moisture treatments increased peak, trough, final viscosity, breakdown and setback in RVA viscograms. The peak viscosity of flour was increased with an increase in temperature and time on roasting and microwave treatments. Suggesting that this increase resulted from inactivation of alpha-amylase in proso millet flour by the treatments.