Spectral dynamics analysis of pesticide residues in banana peel during the ripening process

Banana is one of the most consumed and exported fruits worldwide, with Colombia being the fifth biggest exporter. In order to make bananas more attractive to the global market, quality attributes of this climacteric fruit during the ripening process are a topic of deserve. Particularly, the detection of contamination by pesticides are highly interesting given the hazard effects caused in the ecosystems, and even in human health. In this work, the dynamic of the mid-IR spectral signature left by pesticide residues in banana peel during the ripening process for the pesticides Chlorpyrifos, Malathion and Mancozeb is evaluated. This is done by using ATR-FTIR system along FEDS algorithm to analyze the acquired mid spectra for uncontaminated and contaminated green banana peel at different concentrations and their evolution as the banana ripens. The ripening stages of bananas were determined by analyzing the color properties of luminosity, chromaticity, and color angle, and the Loesecke scale. The stages were classified as green, yellow, and yellow with brown flocks. The presence of pesticide signatures in banana peels during different stages of ripening and at varying concentrations is highlighted using a normalization methodology in the spectral range of interest for each pesticide. To quantify the pesticide signatures, the Pearson's correlation coefficient was used by analyzing the correlation between the FEDS spectra of the target and reference pesticide signals; moreover, this coefficient has been successful used to find correlations among the different stages of banana ripening. The study suggests that pesticides like Malathion, which have higher hydrophilicity, smaller particle size, and rapid degradation over time, may pose a challenge for detection in banana peel using the proposed methodology unlike Chlorpyrifos which showed more promising results. Our study found that the degradation of pesticides in banana peel during the ripening can be detected by analyzing the intensity and the behavior of the signal. Interestingly, the ripening process of bananas was found to accelerate this degradation process. Moreover, we found that the yellow ripening stage is particularly noteworthy, as it exhibits the highest changes in r_fS-P with concentration and with respect to the control samples, indicating a substantial chemical and physical dynamic during the ripening process at this stage. Finally, the study revealed that residues of Chlorpyrifos and Mancozeb pesticides were detected in banana peels even at the ripeness stage deemed safe for human consumption, raising concerns about their potential health risks and their use in the development of industrial products that may impact living organisms.