Effect of Dietary Carotenoids on Reproducers of Amazon River Prawn Macrobrachium amazonicum. Part 2: External Coloration, Accumulation of Astaxanthin in Body Tissues and Pigment Stability in Feed

The color is an important factor to distinguish the commercialized Amazon river prawns. The accumulation of pigments in the body can vary according to the prawn’s diet. In this work, ethanolic extracts of “buriti” and annatto rich in pigments were obtained and tested comparatively with synthetic astaxanthin in the feeding of adults of Macrobrachium amazonicum, together with a control group without pigments and a newly captured wild group. Levels of body pigments were measured using UV reflective spectroscopy and external staining by colorimetry. Differences were observed in the accumulation of astaxanthin in body tissues, differences in saturation between genders and that annatto extract has greater stability in the feed after water immersion (P˂0.05). Further studies are recommended to verify the ideal dosage of natural pigments in relation to synthetic astaxanthin that benefits the productive development of prawns.

Feasibility of Using VIS/NIR Spectroscopy and Multivariate Analysis for Pesticide Residue Detection in Tomatoes

The purpose of this work was to investigate the detection of the pesticide residual (profenofos) in tomatoes by using visible/near-infrared spectroscopy. Therefore, the experiments were performed on 180 tomato samples with different percentages of profenofos pesticide (higher and lower values than the maximum residual limit (MRL)) as compared to the control (no pesticide). VIS/near infrared (NIR) spectral data from pesticide solution and non-pesticide tomato samples (used as control treatment) impregnated with different concentrations of pesticide in the range of 400 to 1050 nm were recorded by a spectrometer. For classification of tomatoes with pesticide content at lower and higher levels of MRL as healthy and unhealthy samples, we used different spectral pre-processing methods with partial least squares discriminant analysis (PLS-DA) models. The Smoothing Moving Average pre-processing method with the standard error of cross validation (SECV) = 4.2767 was selected as the best model for this study. In addition, in the calibration and prediction sets, the percentages of total correctly classified samples were 90 and 91.66%, respectively. Therefore, it can be concluded that reflective spectroscopy (VIS/NIR) can be used as a non-destructive, low-cost, and rapid technique to control the health of tomatoes impregnated with profenofos pesticide.