This study aimed to evaluate the tannin content in the bark of five pine species from a forest harvesting area of the Ixtlán de Juárez community, Oaxaca, México. The species studied were Pinus patula, Pinus ayacahuite, Pinus rudis, Pinus douglasiana, Pinus pseudostrobus. The bark samples were subjected to a drying, grinding, and sieving process. These compounds were extracted using two methods: by constant reflux with ethanol for three hours or in a water bath with distilled water for two hours. The percentage of total extract, Stiasny number, and condensed tannins were quantified. The quantitative number of condensed tannins present in the bark for each of the five species studied ranged from 0.65% to 5.14% for the ethanolic extracts and 0.14% to 1.46% for the aqueous extracts. Analysis by Fourier transform infrared spectroscopy (FTIR) identified polyphenolic compounds and functional groups characteristic of tannins. Analysis by scanning electron microscopy (SEM) and X-ray dispersive spectroscopy (EDX) provided the elemental analysis and chemical composition of the tannin extracts, respectively, finding trace elements of silver, cadmium, phosphorus, iodine, and sulfur, which are minerals present in the soil, meaning that through processes of micronutrient absorption, these can interact with the tannins or polyphenols in the barks of the tree species being studied. The results indicate that the bark of P. patula and P. ayacahuite have a higher concentration of condensed tannins, 5.14% and 4.71%, respectively, in the ethanol extraction, and may be susceptible to exploitation due to the amount of bark generated in forestry activities.

Cotton dyeing is a very complex process with many variables in which different phenomena occur simultaneously. This study aimed to describe the cotton dyeing process by natural dye, using a mathematical model that consists of three mass conservation equations that depict dyeing cotton in cones, taking a representative volume element at the micro, meso, and macroscales. The first equation describes the concentration changes of the dye in the solution, taking into account the diffusive, convective, adsorptive, and reactive effects. The second equation describes the changes in dye concentration in cotton fiber, considering the diffusive, adsorptive, and reactive effects within an intermediate scale. The last equation describes changes in the concentration of dye in the solution on the macroscale, based on the characteristics of the equipment and the difference in concentration before and after passing through the fiber. In addition, a fluid continuity equation was incorporated, taking into account Darcy’s law. In the simulation of the dyeing process with synthetic dye with initial concentrations of 0.408 and 2.06 kg/m³, RMSE of 0.00221 and 0.0289 kg/m³ were obtained, respectively. For the simulation of a dyeing process with natural dyeing, a behavior similar to the experimental data was obtained.

The state of Oaxaca, Mexico obtained the “Pluma” designation of origin in 2022 and has stood out for the production of specialty coffee. Within its process, roasting is one of the stages that contributes to the physical, chemical and sensory quality of the coffee bean. Therefore, the microstructure and elemental chemical composition of special medium-roasted Coffea arabica L beans from six locations with this denomination were analyzed using Scanning Electron Microscopy. The average values of roughness Rz (25.93±2.69-34.18±1.15 and 13.85±1.66-21.85±6.63) and Ra (5.20±0.47- 8.27±0.82 and 6.55±0.94-11.53±1.65) were obtained at 400 and 2000x, respectively. The roasted Coffea arabica L. beans from MAP and HUA are the ones with the greatest roughness and both are located at a lower altitude compared to the rest. PLU and PTO roasted beans showed the highest physical and structural integrity. In all grains, 6C (66.48-81.14%), 8O (18.86-28.69%) and only 20Ca (4.5%) were found on the outside. This research constitutes a standard of authenticity and microstructural and elemental quality of Coffea arabica L. beans with designation of origin "Pluma".