An Application of Image Analysis and Colorimetric Methods on Color Change of Dehydrated Asparagus (Asparagus maritimus L.) (original) (raw)

Shape and color are key factors in quality evaluation of fresh asparagus (Asparagus maritimus L.). Typical green color of asparagus comes from the chlorophyll, pigment which has been degradated during drying process. Th e aim of this paper was to compare color changes of asparagus dried in laboratory tray drier equipment at diff erent temperatures (40 °C, 50 °C, 60 °C and 70 °C) at airfl ow velocity of 2.75 ms -1 . Color changes were obtained by digital image analysis in RGB color model and by chromameter in L * a * b * color model. Basic elements of image analysis system were low voltage halogen lamps with refl ector, digital camera and programs for image pre-processing and analysis. Mean values of color parameters, color changes and correlation coeffi cients for asparagus were calculated for both color models. An analysis showed statistically signifi cant infl uence of drying temperature on hue angle and total color change for both chosen color models of dehydrated asparagus. Represented results show that there was no statistically signifi cant diff erence according to color changes between drying at 50 °C and 60 °C. Calculated correlation coeffi cient between color changes for used models was found to be 0.9167.