engleski

An application of image analysis and colorimetry methods on colour change on dried asparagus (Asparagus maritimus L.)

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 heat process. The aim of this paper was to compare color changes of asparagus dried at different temperatures for data obtained by chromameter CR-300 (Minolta) and digital image analysis in RGB color model. Basic elements of image analysis system were low voltage halogen lamps with reflector, which provided illumination of sample area of 760± ; 5 Lux, digital camera (Panasonic Lumix DMC-FZ30) and programs for image preprocessing and analysis IrfanView, Adobe Photoshop, Global Lab Image/2). Samples were placed at 60 cm from camera. Average values of color, color changes and correlation coefficients for asparagus were calculated for both color models. Average color of sample in beginning was in CIE L*a*b* model L = 21.42, a = -2.77, b = 6.28 and in RGB model R = 140, G = 188, B = 107. Average color changes in Δ Lab = 7.47 were, and in RGB color model were Δ RGB = 37.56. Correlation between changes calculated for used models was found to be 0.55.

colorimetry; image analysis; asparagus; drying

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