AppliedChem, Volume 5, Issue 3 (September 2025) – 10 articles

Myoglobin, a heme protein involved in oxygen storage and transport, also exhibits pseudo-peroxidase activity by catalyzing the breakdown of hydrogen peroxide. While this enzymatic function is well-documented, the potential for substrate inhibition at high hydrogen peroxide concentrations remains underexplored. In this study, we aimed to investigate the kinetic properties of myoglobin’s peroxidase-like activity, focusing on substrate inhibition over time. We employed spectrophotometric assays to monitor reaction rates of myoglobin exposed to increasing hydrogen peroxide concentrations. Our results show that myoglobin activity begins to decline within 3 min of exposure to hydrogen peroxide and reaches full inhibition after approximately 30 min. This progressive inhibition suggests that myoglobin undergoes a delayed inactivation process rather than an immediate loss of function. Additionally, we extended the investigation to hemoglobin, comparing its response to hydrogen peroxide, and preliminary data suggest differences in substrate inhibition dynamics. These findings provide new insights into the regulation of myoglobin’s oxidative function and suggest potential physiological implications for oxidative stress and redox balance, especially in relation to other heme proteins like hemoglobin. Full article

Two different zeolite model clusters were considered in this study to shed light on the release mechanism of a drug, ASA (acetylsalicylic acid), adsorbed on the Y-type zeolite pore walls. Initially, the 3T cluster was employed as a preliminary approach to reveal the trends developed in the acetylsalicylic acid-zeolite system due to the presence of water molecules. Then, the cluster was expanded to 38T (12T:26T), and the adsorption of acetylsalicylic acid in the presence of water molecules inside the pores of the zeolite was studied by employing the hybrid (QM/MM) approximation at the ONIOM2//(HSEH1PBE/6-31+G(d,p):UFF) level of theory. The quantum chemical modeling explicitly shows the water molecules’ impact on the value of the adsorption energy. Specifically, the adsorption energy of acetylsalicylic acid gradually decreases from 32.55 kcal mol⁻¹ (in the case of the 38T model cluster with no H₂O molecules) to 22.10 kcal mol⁻¹ in the presence of three water molecules. Full article

Free radicals are molecules generated during some biochemical processes, and in excess, they can cause various diseases; therefore, their production needs to be controlled in humans. One approach to achieving this is through the consumption of substances with antioxidant capacity, which are capable of neutralizing free radicals. This study evaluated the antioxidant activity of cellooligosaccharides (COS) and xylooligosaccharides (XOS) solutions, extracted from banana leaf and pseudostem, and guava seed cake, unfiltered and filtered using a Sep-pak filter. Additionally, the antioxidant activity of their monomers, including commercial glucose, xylose, and cellobiose, was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. Antioxidant activity was observed in the unfiltered COS and XOS solutions, with maximum DPPH radical reduction of 48.3% and 84.2%, respectively. In filtered COS and XOS solutions, the reduction did not exceed 0.5%. It can be concluded that the antioxidant activity is due to the presence of compounds dissolved in the oligosaccharide solutions, such as lignin, extractives and carboxylic acids, which were qualified by the Folin–Ciocalteu method, nuclear magnetic resonance, and scanning spectrophotometry. Full article

In this work, a set of methods for the study of the physical–chemical properties of flotation processing products was applied to establish parameters for the technological mode of anthropogenic raw material flotation processing using waste paper as an example. The proposed methods include the criterion E_f estimation, which characterizes the interfacial characteristics during flotation, and the criterion J determination, which characterizes the degree of purification of the obtained paper mass. The estimation of criterion E_f is based on the measurement of electric potential difference during flotation. The estimation of criterion J is based on spectrophotometric studies of the flotation product’s optical properties. Based on dispersion analysis, it was established that the proposed criteria are statistically dependent on the variation of the flotation purification mode parameters. The results of the study of flotation processing products show that the criterion E_f is sensitive to the recovery selectivity of dye particles in the froth product. In conjunction with the criterion of optical purity, J, it can be used to assess the effectiveness of proposed solutions of hardware design and the technological mode of flotation separation. Full article

Soybean (Glycine max (L.) Merrill) is a major oilseed crop rich in phytosterols and tocopherols, compounds associated with functional and nutritional properties of vegetable oils. This study aimed to apply, for the first time, Independent Component Analysis (ICA) to discriminate the composition of phytosterols (β-sitosterol, campesterol, stigmasterol) and tocopherols (α, β, γ, δ) in 20 soybean genotypes—14 non-transgenic and six transgenic—cultivated in two major producing regions of Paraná state, Brazil (Londrina and Ponta Grossa). Lipophilic compounds were extracted from soybean seeds, quantified via gas chromatography and HPLC, and statistically analyzed using ICA with the JADE algorithm. The extracted independent components successfully differentiated soybean varieties based on phytochemical profiles. Notably, transgenic cultivars from Ponta Grossa exhibited higher levels of total tocopherols, including α- and β-tocopherol, while conventional cultivars from both regions showed elevated phytosterol content, particularly campesterol and stigmasterol. ICA proved to be a powerful unsupervised method for visualizing patterns in complex compositional data. These findings highlight the significant influence of genotype and growing region on the nutraceutical potential of soybean, and support the use of multivariate analysis as a strategic tool for cultivar selection aimed at enhancing functional quality in food applications. Full article

Corn is one of the most consumed cereals in the Mexican diet. In this country, there are multiple varieties that exhibit nutraceutical potential due to their content of different metabolites with biological activity, such as blue corn. Another variety that has received little study is the red pigmented corn variety Chilac from Puebla, Mexico, which is being studied for its nutraceutical potential. A differential extraction using the Soxhlet method was carried out to evaluate the phenolic content, total flavonoid content, and monomeric anthocyanins, and free radical scavenging test was performed using the DPPH reagent. A proximate analysis was also conducted to identify the main macronutrients. The results of the proximate analysis were comparable to those of other traditional corn varieties, with carbohydrates being the macronutrient present in the highest amount at 77.9%. Regarding phenolic content and the presence of anthocyanins, the best extractions were obtained using alcoholic solvents; for example, ethanol for phenols, yielding 1368.420 ± 104.094 mg of gallic acid equivalents (GAE)/kg plant. In contrast, the flavonoid content was higher in the aqueous extract, with 833.984 ± 65.218 mg QE/Kg. In the case of the DPPH assay, the best result was obtained with ethyl acetate (73.81 ± 5.31%). These findings provide a foundation for expanding the use of corn varieties with nutraceutical potential, opening the possibility of studies focused on deeper characterization. Full article

Biopolymers and bio-based plastics, such as polylactic acid (PLA) and polybutylene succinate (PBS), are recognized as environmentally friendly materials and are widely used, especially in the packaging industry. The purpose of this study was to assess the degradation of PLA- and PBS-based formulations in the forms of granules and films under controlled composting conditions at a laboratory scale. Biodegradation tests of bio-based materials were conducted under controlled aerobic conditions, following the standard EVS-EN ISO 14855-1:2012. Scanning electron microscopy (SEM) was performed using a high-resolution Zeiss Ultra 55 scanning electron microscope to analyze the samples. After the six-month laboratory-scale composting experiment, it was observed that the PLA-based materials degraded by 47.46–98.34%, while the PBS-based materials exhibited a final degradation degree of 34.15–80.36%. Additionally, the PLA-based compounds displayed a variable total organic carbon (TOC) content ranging from 38% to 56%. In contrast, the PBS-based compounds exhibited a more consistent TOC content, with a narrow range from 53% to 54%. These findings demonstrate that bioplastics can contribute to reducing plastic waste through controlled composting, but their degradation efficiency depends on the material composition and environmental conditions. Future efforts should optimize bioplastic formulations and composting systems while developing supportive policies for wider adoption. Full article

As demand for plant-based beverages grows, analytical tools are needed to classify and understand their structural and compositional diversity. This study applied a multi-analytical approach to characterize 41 commercial almond-, oat-, rice- and soy-based beverages, evaluating attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, protein secondary structure proportions, colorimetry, and microscopic image texture analysis. A total of 26 variables, derived from ATR-FTIR and protein secondary structure assessment, were employed in multivariate models, using partial least squares discriminant analysis (PLS-DA) and orthogonal PLS-DA (OPLS-DA) to evaluate classification performance. The results indicated clear group separation, with soy and rice beverages forming distinct clusters while almond and oat samples showing partial overlap. Variable importance in projection (VIP) scores revealed that β-turn and α-helix protein structures, along with carbohydrate-associated spectral bands, were the key features for beverages’ classification. Textural features derived from microscopy images correlated with sugar and carbohydrate content and color parameters were also employed to describe beverages’ differences related to sugar content and visual appearance in terms of homogeneity. These findings demonstrate that combining ATR-FTIR spectral data with protein secondary structure data enables the effective classification of plant-based beverages, while microscopic image textural and color parameters offer additional extended product characterization. Full article

In this study, chromium ferrite (FeCr; CrFe₂O₄) nanoparticles supported on activated carbon (AC), obtained from agricultural olive mill solid waste, were synthesized via a simple hydrothermal process. The structural, morphological, optical, and chemical properties of the FeCr/AC composite were characterized using XRD, SEM, EDX, DRS, BET, and FTIR techniques. The FeCr/AC composite was applied as a heterogeneous photo-Fenton catalyst for the degradation of methylene blue (MB) dye in an aqueous solution under 25 W visible-light LED irradiation. Critical operational factors, such as FeCr/AC dosage, pH, MB concentration, and H₂O₂ levels, were optimized. Under optimal conditions, 97.56% of MB was removed within 120 min of visible-light exposure, following pseudo-first-order kinetics. The composite also exhibited high efficiency in degrading methyl orange dye (95%) and tetracycline antibiotic (88%) within 180 min, with corresponding first-order rate constants of 0.0225 min⁻¹ and 0.0115 min⁻¹, respectively. This study highlights the potential of FeCr/AC for treating water contaminated with dyes and pharmaceuticals, in line with the Sustainable Development Goals (SDGs) for water purification. Full article

The aim of this work was to improve the technology for obtaining coating based on plasticized polylactide from its aqueous suspensions. For this purpose, a film formation process with additional heating was developed, and the influence of plasticizers on the film-formation temperature was investigated. It is shown that using only mechanical emulsification, it is possible to obtain a material with an average particle size of 2.4 microns, which is suitable for further research and modification for film materials. The introduction of epoxidized fatty acids (oleic and linolic) was found to reduce the film-formation temperature by 20–30 °C compared to the unplasticized polymer, which puts them on par with the classical plasticizer, polyethylene glycol, reducing the film-formation temperature by 36% at the same concentration. Full article