Color, Microstructure and Crystallinity of Red Rice Flour with Differences in Drying Times and Temperatures
Abstract
One effort to develop red rice as food is to process it into flour. Drying is one of the stages in the flour processing that must be considered to get flour with good physicochemical characteristics. Time and temperature of drying are some of the factors that influence the physicochemical characteristics of dried food products. This research aimed to study the color changes, microstructure and crystallinity properties of red rice flour which were dried with different times and temperatures. The factors were drying time (1 hour, 2 hours, and 3 hours) and drying temperature (50, 55, and 60 oC). The results showed that interaction of drying time and drying temperature significantly increased lightness and yellowness, but reduced the redness of red rice flour. Granular morphology images and crystallinity pattern showed that differences in drying time and temperature did not affect the shape of the granules and type of starch of red rice flour. Based on the crystallinity pattern, red rice flour was classified as A- type.