The increasing need for sustainable construction materials has prompted research into alternatives to Ordinary Portland Cement (OPC), a major contributor to global CO₂ emissions. Geopolymers, synthesized via alkali activation of aluminosilicate precursors such as metakaolin and fly ash, are a promising alternative, reducing up to 80% of carbon emissions. However, their long-term durability in aggressive chemical environments, particularly when up against organic acids, remains insufficient. While mineral and inorganic acid resistance have been studied, the impact of naturally occurring organic acids like oxalic acid (Ox)—commonly found in soils and organic-rich sediments—has received limited attention. Ox is known to chelate metal ions and alter mineral phases, potentially affecting the integrity of geopolymer matrices. This study investigates the degradation behavior of geopolymers under continuous exposure to Ox (0.2, 0.4, and 0.6 M) at 25 °C using a flow-through reactor. Mass loss over time was monitored to determine reaction kinetics, while SEM, FT-IR, XRD, and EDS analyses were conducted to evaluate microstructural and chemical changes. The results revealed significant alterations in the geopolymers’ structures due to Ox exposure, providing key insights into their vulnerability to organic acid attack. These findings indicate the importance of considering organic acid interactions in long-term performance assessments of geopolymers.

Food coloring are additives that are usually incorporated into foods to make them more attractive to people. However, some mineral and synthetic dyes used in the food industry are related to harmful effects on human health. Natural dyes, such as betalains extracted from prickly-pear fruit, have fewer restrictions on use and represent a healthier alternative to enhance the appearance of food. In this work, a process to extract betalains from the pulp and peel of Cardona prickly-pear fruit was implemented and optimized. The extracted pigment was encapsulated in cornstarch. Then, it was analyzed the effect of the extract/encapsulant ratio on the amount of encapsulated betalains. It was found that the peel of this variety of prickly-pear fruit represents about 48% of its total weight. It was also demonstrated that concentrations of betalains in the peel (12.0 mg/g) and in the pulp (16.5 mg/g) are alike. For these reasons, we consider that the peel of red prickly-pear fruit is an ideal material for the extraction of betalains because it is a waste material with high content of red pigments.

Las emisiones solares pueden provocar daños en la piel de los seres humanos, ocasionando distintas lesiones y en casos extremos, cáncer de piel. Para evitar estos riesgos existe una gran variedad de protectores solares que ofrecen distintos niveles de protección; sin embargo, algunos compuestos químicos pueden tener efectos secundarios por lo que se están investigando otras opciones de protección solar, tales como los extractos de origen vegetal que tienen un efecto positivo en la protección de la piel. Para esta investigación se obtuvieron extractos hidroalcohólicos de fresa y espinaca; así como mucílago de semillas chía y un protector solar comercial. Con estos materiales se elaboraron disoluciones que luego se emplearon para generar varias mezclas con diferentes proporciones en sus componentes. Posteriormente, se utilizó el método propuesto por Mansur et al. (1986) para estimar el factor de protección solar de las muestras; tanto de los extractos individuales, como de las mezclas de extractos. En las disoluciones con extractos individuales se destaca el FPS de los extractos de fresa y espinaca. Entre las mezclas, la que tuvo mejores resultados fue la mezcla con 30% de espinaca y 70% de bloqueador comercial que presenta un FPS de 22.28; seguida por la mezcla con 30% de fresa y 70% de bloqueador con FPS de 20.78, lo que nos indica que los extractos vegetales producen un impacto positivo en la actividad fotoprotectora de las formulaciones. También se observó que, al mezclar algunos agentes activos, el FPS de la formulación resultante fue mayor que el de los componentes individuales. Esto indica que en algunas mezclas se presentan efectos sinérgicos que intensifican la actividad fotoprotectora de las formulaciones.

The Mexican marigold flower (Tagetes erecta) is a plant native to Mexico, the uses are: pigments, flavoring, perfumery, ornamental, insecticides, nematicides and medicinal. In the soil there is a great richness of microorganisms mycorrhizal fungi and plant growth promoting rhizobacteria with an important role in the processes that affect the transformation of nutrients in the soil and their availability for plants and protection against phytopathogenic microorganisms. The objective of this work was to evaluate the effect of the use of beneficial microorganisms in the development of the cempasúchil flower compared with the application of a fertilizer. The bacterial strains were identified as 225, 254, 302 and an inoculum of mycorrhizal fungi. The Blue Garden fertilizer. Fresh weight, dry weight, number of flowers, root size were determined. A completely randomized experimental design and Tukey test were used. According to the results obtained, the best treatments that could have a potential use were the following treatments: fertilizer, strain 254, strain 302 and strain 254 and mycorrhiza. The use of beneficial microorganisms for the production of Mexican marigold flowers was shown to be effective and comparable with the application of fertilizer, therefore reducing its use and even eliminating it.

The increasing need for sustainable construction materials has prompted research into alternatives to Ordinary Portland Cement (OPC), a major contributor to global CO₂ emissions. Geopolymers, synthesized via alkali activation of aluminosilicate precursors such as metakaolin and fly ash are a promising alternative reducing up to 80% carbon emissions. However, their long-term durability under aggressive chemical environments, particularly against organic acids, remains insufficient. While mineral and inorganic acid resistance has been studied, the impact of naturally occurring organic acids like oxalic acid (Ox) —commonly found in soils and organic-rich sediments—has received limited attention. Ox is known to chelate metal ions and alter mineral phases, potentially affecting the integrity of geopolymer matrices. This study investigates the degradation behavior of geopolymers under continuous exposure to Ox (0.2, 0.4, and 0.6 M) at 25 °C using a flow-through reactor. Mass loss over time was monitored to determine reaction kinetics, while SEM, FT-IR, XRD, and EDS analyses were conducted to evaluate microstructural and chemical changes. Results revealed significant alterations in geopolymer structure due to Ox exposure, providing key insights into their vulnerability to organic acid attack. These findings remark the importance of considering organic acid interactions in the long-term performance assessment of geopolymers.

In this work, some spectral characteristics of oat mucilage were studied to obtain a deep and detailed knowledge about the possible application of this material in the absorption of dangerous ultraviolet radiation for human skin. For this purpose, the mucilage of oat was extracted and purified by adapting a previously reported method. Then, several aqueous solutions with different known concentrations of this extract were prepared. These solutions were analyzed with a spectrophotometer to determine their absorbance between 200 and 1000 nm. Through the absorbance spectra, the photoprotective capacity of the mucilage of oat in aqueous solution was evaluated. The extinction coefficient of this material was also calculated through spectrophotometric measurements and the Lambert-Beer Law. In addition, a cream with natural ingredients and oat mucilage as active compound was prepared to evaluate its sun protection factor and compare it with that of the aqueous mucilage. Finally, the feasibility of using the mucilage of oat as active ingredient in effective and safe sunscreens for people and the environment was analyzed.