Effect of the drying process on saffron petals color Features using the vision machine

Iran is the largest producer of saffron and more than 90 percent of Iran's saffron is produced in Iran.Drying is one of the methods commonly used to increase the shelf life of medicinal plants and agricultural products. In this study, drying process of saffron petals with thin layer hot air dryer at five levels at 40, 60, 80, 100 and 120 ° C and three air flow of 0.5, 1 and 1.5 m/s and their impacts of on colored parameter (amounts R, G and B) have been studied. By using vision machine system, color images of the saffron dried petals were taken, and analyzed using image processing algorithms, Features colored (RGB) were also obtained. In addition, the anthocyanin content, (using differential pH method) and L*a*b* characteristics were measured in order to determine the proper drying conditions of the samples. The data were analyzed using factorial experiment based on randomized complete design. The results showed that maximum RGB values were at the temperature range of 80 to 100°C, representing the greatest ratio and intensity of red, green and blue colors. Also in this temperature range, the highest anthocyanin content (482.21mg/l) and lowest color changes (ΔE) were obtained which was a relative desirability of this range for drying saffron petals.