APLIKASI METODE SIMPLE DIGITAL IMAGING UNTUK MEMPREDIKSI PEMBENTUKAN WARNA TEPUNG HASIL PENGOLAHAN UMBI UWI UNGU (Dioscorea alata)

This research was conducted to determine the effect of citric acid concentration and length of blanching on the color formation in Dioscorea alata ’s flour and to obtain models which can be used to predict the color formation in Dioscorea alata ’s flour. The study used local purple tuber of Dioscorea alata .  The experiment was carried out in two replication using two factors.  The first factor was citric acid concentration (0,0.25,0.5, 0.75 and 1%) and the second factor was length of blanching (0, 5, 10, 15, and 20 minutes).  The results showed that citric acid concentration was not significantly affect all color parameters (L*, a*, b*, Hue, and index browning).  The models which can be used to predict the color of Dioscorea alata ’s flour are : L* = 86.9 -2.37X + 0.06X 2 , a* = 3.9 + 1.12X - 0.03X 2 , b* = 9.4 -1.7X + 0.04X 2 , Sudut Hue = 2.56 + 33.59X – 0.87X 2 , Indeks browning = 324.48 + 1.27X, where X is the length of blanching in minutes. Key words : Dioscorea alata , citric acid, length of blanching