Linear Polarized Transmission Resonance Raman Studies in Fruits: Experimental Versus Model Calculations

A linear polarized transmission resonance Raman spectroscopic technique was developed to measure the depolarization ratio of different β-carotene Raman bands in carrot roots and mangos. Basically, this optical property was measured as a function of the vegetal tissue thickness and fruit postharvest lifetime. In general, the depolarization ratio increases as the sample optical thickness does and decreases as the fruit postharvest lifetime increases. In addition, a previous theoretical model was extended by considering the light state of polarization to obtain the depolarization ratio as a function of the sample absorption and scattering coefficient. It was shown how the reported theoretical model is able to satisfactorily describe the fruit optical parameter dependence on both the sample thickness and its postharvest time. Finally, the advantages and limitations of the present technique and theoretical mode are discussed.