Evaluation of polycyclic aromatic hydrocarbons in sediments of Balsas River Mouth, Pacific Coast, Mexico: Sources, risks, and genotoxicity.

Polycyclic aromatic hydrocarbons (PAHs) were assessed in sediments (n = 7) collected from the mouth of the Balsas River, Pacific Coast, Mexico. The total PAH levels ranged between 142.1 and 3944.07 µg kg-1 in the summer and 137.65-3967.38 µg kg-1 in the winter, probably reflecting the anthropogenic activities of the region. Calculation of the four analytical ratios of [Anthracene/(Anthracene + Phenanthrene)]: [Fluoranthene/(Fluoranthene + Pyrene)], [Fluoranthene/Pyrene: Fluoranthene/(Fluoranthene + Pyrene)], [Indeno [123-cd]Pyrene/(Indeno [123-cd]Pyrene + Benzo [ghi]Perylene)]: [Benzo [a]anthracene/(Benzo [a]Anthracene + Chrysene)], and [Anthracene/Phenanthrene]: [Fluoranthene/(Fluoranthene + Pyrene)] revealed a mixed PAH source, from petroleum and biomass combustion. Significant statistical correlations (r2 = 0.90) between the 4 and 5 ringed PAHs denote that adsorption is the principal mechanism for accumulation in sedimentary archives. Ecotoxicological indices (Mean Effect Range Medium Quotient and Mean Probable Effect Level Quotient) indicated moderate pollution with adverse biological impacts on ambient benthonic organisms. The calculations of Toxicity Equivalent Quotient and Mutagen Equivalent Quotient values proposed that the region is highly polluted by mutagenic and carcinogenic PAH compounds. The genotoxic evaluation of Lutjanus guttatus (Spotted rose snapper) presented significant DNA damage and discrepancies in Ethoxyresorufin-O-Deethylase activity. Based on the toxicological and genotoxicological evaluation of PAHs in sediments, the region was observed to be largely impacted from biological damage.

Comparative pyrolysis studies of lignocellulosic biomasses: Online gas quantification, kinetics triplets, and thermodynamic parameters of the process.

This study focused on the analysis of the pyrolytic behavior of four lignocellulosic biomasses: avocado stone (AS), Agave salmiana bagasse (AB), cocoa shell (CS), and α-cellulose (CEL). According to the triplet kinetics analysis, the order of pyrolytic decomposition was AS < AB < CEL < CS. The AS was dominated by a second-order reaction, while AB followed a 2D diffusion-Valensi model. On the other hand, the pyrolysis of CS starts with an nth-order reaction and ends random nucleation model, and CEL was dominated by one-dimensional diffusion and first-order reaction. Thermodynamic studies reveal that the difference between the activation energy versus enthalpy change was<6.5 kJ/mol for all biomasses, thus showing the ease of pyrolysis reaction of these biomasses. Furthermore, the AS and AB showed that the reactions are close to thermodynamic equilibrium and stability, whereas CS and CEL indicated high reactivity.

Evaluation of Cocoa Beans Shell Powder as a Bioadsorbent of Congo Red Dye Aqueous Solutions.

The use of synthetic dyes in the textile, leather, and paper industries is a source of groundwater pollution around the world. There are different methods for the treatment of wastewater that has been contaminated with dyes, among which adsorption with agro-industrial wastes is gaining relevance. In the present study, the adsorption capacity of cocoa bean shell powder was evaluated when it was used as a bioadsorbent for Congo red dye in an aqueous medium. A 24 central factorial design with central and axial points was proposed to determine the adsorption capacity. The factors that were studied were the adsorbent (0.06-0.15 g), Congo red (40-120 mg L-1), pH (3-11), and time (4-36 h). The bioadsorbent was characterized through scanning electron microscopy and Fourier-transform infrared spectroscopy. The effects of the factors on the adsorption capacity for Congo red using cocoa bean shell were nonlinear, and they were modeled with a second-order polynomial (p < 0.05) and with an R2 of 0.84. The bioadsorbent obtained a maximum adsorption of 89.96% in runs. The process of optimization by using the surface response allowed the maximization of the adsorption, and the validation showed that 95.79% adsorption of the dye was obtained.

Continuous Microalgal Cultivation for Antioxidants Production.

Microalgae, including cyanobacteria, represent a valuable source of natural compounds that have remarkable bioactive properties. Each microalga species produces a mixture of antioxidants with different amounts of each compound. Three aspects are important in the production of bioactive compounds: the microalga species, the medium composition including light supplied and the photobioreactor design, and operation characteristics. In this study, the antioxidant content and productivity performance of four microalgae were assessed in batch and continuous cultures. Biomass productivity by the four microalgae was substantially enhanced under continuous cultivation by 5.9 to 6.3 times in comparison with batch cultures. The energetic yield, under the experimental conditions studied, ranged from 0.03 to 0.041 g biomass kJ-1. Phenols, terpenoids, and alkaloids were produced by Spirulinaplatensis, Isochrysisgalbana, and Tetraselmissuecica, whereas tocopherols and carotenoids were produced by the four microalgae, except for phycocyanin and allophycocyanin, which were only produced by S. platensis and Porphyridiumcruentum. The findings demonstrate that the continuous cultivation of microalgae in photobioreactors is a convenient method of efficiently producing antioxidants.

Extracción de compuestos solubles de la cascarilla de cacao con CO2 supercrítico. Caso de metilxantinas y grasa / Extraction of soluble compounds from cocoa shell with supercritical CO2 . A methilxantines and fat case

Resumen La extracción supercrítica es una técnica efectiva para separar diversos compuestos desde matrices naturales, por las propiedades que le confiere a los solventes como el CO2en estado supercrítico. El objetivo del presente trabajo fue la extracción supercrítica de teobromina, cafeína y grasa de la cascarilla de cacao con CO2supercrítico. Se propuso un diseño 22 con 5 puntos centrales, en condiciones estáticas de extracción, teniendo como factores de estudio, presión (2 000 psi a 6 000 psi) y temperatura (318 K a 333 K). Se analizaron los residuos en la cámara de extracción para evaluar los porcentajes de remoción y residual de grasa, cafeína y teobromina, respectivamente. Los resultados mostraron un rendimiento entre 1.72 % a 9.57 %, con una razón de remoción para grasa y cafeína de 61.31 % a 94.54 % y 38.52 % a 78.38 %, respectivamente. La teobromina se retuvo en el polvo de la cascarilla con una razón residual mayor a 90 %. Los efectos de las variables de temperatura y presión para la remoción de grasa fueron predichos a través de un polinomio de primer orden con efectos de interacción, no así para cafeína o teobromina. El método de extracción fue eficiente para remover grasa y cafeína, quedando un residuo en la cámara de extracción considerado como rico en compuestos funcionales.

Abstract Supercritical extraction is an effective technique for separating various compounds from natural matrices due to the properties from solvents, such as CO2, in supercritical state. In the present work, the supercritical extraction of theobromine, caffeine and fat from cocoa shell was carried out with supercritical CO2. A 22 design with 5 central points was proposed, with static operation conditions, having pressure (2 000 psi to 6 000 psi) and extraction temperature (318 K to 333 K) as study factors. The residues were analyzed in the extraction chamber to evaluate the removal and residual percentages of fat, caffeine and theobromine, respectively. The results showed a yield between 1.72 % to 9.57 %, with a removal rate for fat and caffeine of 61.31 % to 94.54 % and 38.52 % to 78.38 %, respectively. The theobromine was retained in the shell powder with a residual ratio greater than 90 %. The effects of temperature and pressure for fat were predicted through a first-order polynomial with interaction effects, but not for caffeine or theobromine. The extraction method was efficient to remove fat and caffeine, leaving a residue powder in the extraction chamber considered as high in functional compounds.

Relationship between fermentation index and other biochemical changes evaluated during the fermentation of Mexican cocoa (Theobroma cacao) beans.

BACKGROUND: During traditional cocoa processing, the end of fermentation is empirically determined by the workers; consequently, a high variability on the quality of fermented cocoa beans is observed. Some physicochemical properties (such as fermentation index) have been used to measure the degree of fermentation and changes in quality, but only after the fermentation process has concluded, using dried cocoa beans. This would suggest that it is necessary to establish a relationship between the chemical changes inside the cocoa bean and the fermentation conditions during the fermentation in order to standardize the process. RESULTS: Cocoa beans were traditionally fermented inside wooden boxes, sampled every 24 h and analyzed to evaluate fermentation changes in complete bean, cotyledon and dried beans. The value of the fermentation index suggested as the minimal adequate (≥1) was observed at 72 h in all bean parts analyzed. At this time, values of pH, spectral absorption, total protein hydrolysis and vicilin-class globulins of fermented beans suggested that they were well fermented. CONCLUSION: Since no difference was found between the types of samples, the pH value could be used as a first indicator of the end of the fermentation and confirmed by evaluation of the fermentation index using undried samples, during the process.