Influence of Drying Temperature on the Changes of Colour in Green Banana Flour Following Infrared Radiation Heating

The visual appearance of flour is one factor that influences consumer choice in several ways, the purpose of this study was to examine the impact of three different drying temperatures (55, 60, and 65°C) on the colour characteristics of green banana flour and the associated process variables. The study involved conducting experiments utilizing a far-infrared power of 3000 watts. The drying process resulted in a reduction of the moisture content to a range of 10 to 12% dry basis. The CIE L*a*b* system was employed to define the colour parameters. These parameters were used to calculate the hue angle (°h), browning index, chroma, and total colour change (ΔE*). The L* value exhibited a reduction, whilst the a* and b* values demonstrated an increase in response to the rise in temperature. The drying temperature of 65°C resulted in the least noticeable change in colour, followed by 60°C and 55°C. The corresponding drying times were 210, 300, and 330 minutes, respectively. Drying at 65 °C provided the least lightness, resulting in a browner product colour than the other drying temperatures and the highest browning index due to the partial Maillard reaction that may have occurred due to high amounts of starch and protein, including the high temperatures. Keywords : Far-infrared, Drying, Banana flours, Colour