Characterization of diffuse reflectance spectrum from fruit plant leaves as chlorophyll concentration measurement technique

Fruit consumption rate of Indonesian population is still far below the level of sufficiency of fruits consumption recommended by the Food Agriculture Organization / World Health Organization (FAO / WHO). Maintaining the quality of fruit is expected to maintain stability in the fulfillment of national fruit needs. Early detection to determine the growth rate can be seen from the level of greenery or chlorophyll content during the growth period. So we need a method to measure the concentration of chlorophyll in the leaves by using Diffuse Reflectance Spectroscopy which is non destructive. This technique does not require complicated sample preparation as in the determination of chlorophyll content through Absorption Spectroscopy. Tissue model of leaf (phantom) is made of gelatin with known chlorophyll content variation, used as a preliminary stage for testing Diffuse Reflectance Spectroscopy technique. Determination of chlorophyll content by Absorption Spectroscopy technique will be used as a comparison. To determine the value of optical parameters (absorption coefficient μ_a and reduced scattering coefficient μ_s'), obtained from fitting between the measured reflectance spectra of phantom and the reflectance model of leaves. Chlorophyll content determined from correlation equation y = 0,944 x + 5,0069 with a coefficient of determination (R²) of 0,9422 for mango leaves, y = 0,5759 x + 5,6772 with coefficient of determination (R²) of 0.9945 for starfruit leaves, y = 0,1168 x + 3,7704 with a coefficient of determination (R²) of 0.9789 for guava leaves.