Simplex Centroid Mixture Design Research Articles

Anaerobic co-digestion of microalgal biomass, sugarcane vinasse, and residual glycerol from biodiesel using simplex-centroid mixture design: methane potential, synergic effect, and microbial diversity.

Microalgal biomass (MB) is a promising feedstock for bioenergy production. Nonetheless, the cell recalcitrance and the low C/N ratio limit the methane yield during anaerobic digestion. As an alternative to overcome these challenges, MB co-digestion with different feedstocks has been proposed. Thus, this study evaluated the anaerobic co-digestion (AcoD) of MB cultivated in wastewater with sugarcane vinasse (VIN) and residual glycerol from biodiesel production (GLY). Batch tests were conducted using augmented simplex-centroid mixture design to investigate the impact of AcoD on methane production (SMP), synergistic effects, and the influence on microbial community. When compared to MB digestion, 150 NmL CH4.g-1VS, binary and ternary AcoD achieved SMP increases from 120 to 337%. The combination of 16.7:16.7:66.7 (MB:VIN:GLY) showed the highest SMP for a ternary mixture (631 NmL CH4.g-1VS). Optimal synergies ranged from 1.3 to 1.4 and were primarily found for the MB:GLY AcoD. Acetoclastic Methanosaeta genus was predominant, regardless the combination between substrates. Despite the largest SMP obtained from the MB:GLY AcoD, other ternary mixtures were also highly synergetic and therefore had strong potential as a strategic renewable energy source.

Oil-in-water emulsion loaded with optimized antioxidant blend improved the shelf-life of trout (Oncorhynchus mykiss) fillets: a study with simplex-centroid design.

This study aimed to obtain optimized mixture with three essential oils (EOs) for maximum antioxidant activity through the augmented simplex-centroid mixture design and evaluate the effect of this optimized blend on total aerobic psychrotrophic count (TAPC), lipid and protein oxidation, instrumental color parameters and texture profile in rainbow trout fillets at refrigerated storage for nine days. Considering the DPPH and FRAP assays, the ideal EO blend was 66% lemongrass and 34% oregano. During refrigerated storage, this blend at 2000ppm was equally effective as BHT (100ppm) (p > 0.05), mitigating the discoloration (a* and b*), lipid, and protein oxidation in 38.83%, 12.95%, 76.13%, and 35.13%, respectively, besides shows greater effectiveness for preserving texture changes (p < 0.05) and extending the shelf life in 13h. The lemongrass + oregano EO blend reveals a promising natural alternative to enhance the quality of rainbow trout fillets under refrigerated storage. Furthermore, the multiresponse optimization showed to be a strong ally in enabling the use of these EOs by food industries.

Rice Husk, Brewer's Spent Grain, and Vine Shoot Trimmings as Raw Materials for Sustainable Enzyme Production.

Solid by-products with lignocellulosic structures are considered appropriate substrates for solid-state fermentation (SSF) to produce enzymes with diverse industrial applications. In this work, brewer's spent grain (BSG), rice husk (RH), and vine shoot trimmings (VSTs) were employed as substrates in SSF with Aspergillus niger CECT 2088 to produce cellulases, xylanases, and amylases. The addition of 2% (NH4)2SO4 and 1% K2HPO4 to by-products had a positive effect on enzyme production. Substrate particle size influenced enzyme activity and the overall highest activities were achieved at the largest particle size (10 mm) of BSG and RH and a size of 4 mm for VSTs. Optimal substrate composition was predicted using a simplex centroid mixture design. The highest activities were obtained using 100% BSG for β-glucosidase (363 U/g) and endo-1,4-β-glucanase (189 U/g), 87% BSG and 13% RH for xylanase (627 U/g), and 72% BSG and 28% RH for amylase (263 U/g). Besides the optimal values found, mixtures of BSG with RH or VSTs proved to be alternative substrates to BSG alone. These findings demonstrate that SSF bioprocessing of BSG individually or in mixtures with RH and VSTs is an efficient and sustainable strategy to produce enzymes of significant industrial interest within the circular economy guidelines.

Influence of the simplex-centroid mixture design on the texture of sauces with different food

The use of different food matrices can result in products with different textures. In this context, the objective was to develop sauces with a mixture of tomato, pumpkin and mango pulp, using the centroid simplex design. The texture of the sauces was studied instrumentally (consistometer and texturometer) and sensorially (Acceptance and Acceptability Index – AI%). What adjusted the flow, measured in a consistometer (from 1.40 to 5.50 cm), firmness (from 51.90 to 112.54 N), consistency (1322.66 to 2864.35 N.s-1), cohesiveness (-30.31 to -87.10 N), viscosity index (-757.57 to -1933.60 N.s-1) and consistency acceptance (4.42 to 7.84) to the predictive model linear, while the AI was greater than 70%. The sauces were accepted for their satisfactory consistency, with no significant influence on the texture of the sauces, demonstrating the possibility of implementing different food matrices without compromising the consumer's taste.

Optimization in the reprocessing of recycled polyamide 6 reinforced with 30 wt% Glass Fiber (PA6/GF30) using mixture design

AbstractIn the present study, polyamide 6 reinforced with 30 wt% Glass fiber (PA6/GF30) used in automotive industry was reprocessed via injection molding. The virgin and recycled PA6/GF30 samples were characterized by chemical, rheological, mechanical, and morphological properties as a function of the number of processing cycles. After each reprocessing cycle, a decrement in mechanical properties in tensile, bending, and impact strength was revealed for different combination of cycle number (N0 [for the virgin PA6/GF30], N1 [for the first recycled PA6/GF30], N2 [for the second recycled PA6/GF30], and N3 [third recycled PA6/GF30 sample]) in the composite mixture. A simplex‐centroid mixture design (SCMD) was used to evaluate the effect of combining Ni (i=0,1,2) on the mechanical properties of composite samples for optimization. Graphical comparison of experimental results using regression models showed a high degree of correlation. Results revealed that the ternary N0N1N2 blends composite made up of 67.97 wt% N0, 23.13 wt% N1, and 8.89 wt% N2 exhibited the best mechanical properties. Furthermore, a good correlation between the scanning electron microscopy (SEM) observations and tensile test results was observed. Hence, the new reprocessed formulation presents a cost‐effective alternative of virgin PA6/GF30 for different engineering applications.

Utilization of Peach-palm waste for cost-effective amylase production by Trichoderma stromaticum: Stability and industrial potential

ABSTRACT Amylases are among the most important enzymes for biotechnological and industrial applications. The present work aimed to analyse the use of agro-industrial waste as a low-cost substrate to the obtention of the amylase by the fungus Trichoderma stromaticum AM7 (CCMB617P) under solid state fermentation (SSF). The fungus was able to produce amylase using solely peach palm waste as a substrate (29.2 U/gds), however when a simplex centroid mixture design was applied to optimise the composition of the nitrogen source, peptone, and ammonium phosphate (7:3 w/w) in a total of 1% were added and an increase of the 45% (42.4 U/gds) was observed in relation to the activity initially obtained. The physicochemical characterisation of amylase revealed the optimum activity at pH 4.0 and temperature 50 °C to 60 °C. The amylase retained around 90% of its activity in a pH range from 4.0 to 7.0 and a temperature 40 °C to 70 °C, and 60% in a range from 80 °C to 100 °C, for up to 1 h. Amylase showed an increase in its activity with Al2+, Ag2+, and Co2+, however, the Cu2+negatively influenced the enzymatic activity. The enzyme was stable in the presence of SDS and β-mercaptoethanol. The cost-effective enzyme extraction and stable amylase highlight its strong potential in industry applications, especially in food processes.

Mixture design of α-pinene, α-terpineol, and 1,8-cineole: Amultiobjective response followed by chemometric approaches to optimize the antibacterial effect against various bacteria and antioxidant activity.

α-Pinene, α-terpineol, and 1,8-cineole are compounds naturally present in essential oils, although their amounts vary from oil to oil. Although several studies have reported their antibacterial and antioxidant effects, there are few reports on the synergistic or antagonistic effects of their combinations. The objective of this study was to investigate the combined antibacterial effect of these three compounds. To our knowledge, this is the first report on the prediction of their optimal combination using the mixture design approach. The experimental antibacterial activity of the α-pinene, α-terpineol, and 1,8-cineole mixtures depended on the proportion of each compound in the mixture and the target strain, with minimum inhibitory concentrations (MIC) ranging from 0.31 to 1.85 mg/mL. Using the increased simplex-centroid mixture design, the mixture containing 0.33% of each molecule proved to be the most effective against Bacillus cereus and had the lowest MIC values. In addition, α-pinene, α-terpineol, and 1,8-cineole showed significant antioxidant activity against 2,2-picryl-1-hydrazyl radical (DPPH), with IC50 values of 24.53 ± 0.05, 65.63 ± 0.71, and 63.58 ± 0.01 μg/mL, respectively. Statistical planning and the development of utility profiles of the substance mixtures can predict the optimal composition that will exhibit the highest antibacterial activity against B. cereus as well as antioxidant properties. Furthermore, the synergistic effect of the mixtures can contribute significantly to their successful use as natural preservatives in various applications.

Optimization strategy for inulinase production by Aspergillus niger URM5741 and its biochemical characterization, kinetic/thermodynamic study, and application on inulin and sucrose hydrolysis.

Inulinases are enzymes of great interest in the food industry, especially due to their application in the synthesis of fructose and fructo-oligosaccharides. Moreover, some inulinases (I) also present invertase activity (S), making them useful for sucrose hydrolysis processes. In the present study, the production of inulinase by Aspergillus niger URM5741 was evaluated and optimized using two statistical approaches. First, the composition of the cultivation medium was determined through a simplex centroid mixture design, followed by the selection of optimal fermentation conditions using the Box-Behnken design. Based on these experimental designs, the maximum activities of inulinase (16.68 U mL-1) and invertase (27.80 U mL-1) were achieved using a mixture of wheat, soy, and oat brans (5g), along with 2.5% inulin and 40% moisture. The inulinase exhibited optimum temperature and pH of 60°C and 4.0, respectively, displayed a high affinity for both substrates, as evidenced by very-low Michaelis constant values (1.07-1.54mM). A relative thermostability was observed at 55-60°C as indicated by half-lives values (I: 169.06-137.27min; S: 173.29-141.52min) and D-values (I: 561.61-456.00min; S: 575.65-470.11min) which were further confirmed by the high activation energy (123.01 and 143.29kJmol-1). The enzyme demonstrated favorable results in terms of inulin and sucrose hydrolysis, being a maximum release of reducing sugars of 6.04 and 15.80g L-1, respectively. These results indicate that the sequential statistical approach proved to be beneficial to produce inulinase by A. niger URM5741, with the obtained enzyme considered promising for long-term industrial applications.

Digital twin of biomass/coal co-firing circulating fluidized bed boiler by using computational fluid dynamics simulation

Combining biomass fuel with coal in circulating fluidized bed (CFB) boilers is attractive as the increasing of energy demand. The characteristics of biomass/coal co-firing in the industrial boiler are then investigated using computational fluid dynamics (CFD). In this study, fuels of interest are coal, wood chips, and bark. The fuel proportions were set for investigating their effects on the combustion using a simplex centroid mixture design. CFD simulations consist of a standard k-epsilon viscosity flow model, Euler multiphase fluid flow model, and a simplified biomass-char combustion reaction model. The predictive responses of the model are bed temperature, heat flux, and carbon dioxide (CO2) and carbon monoxide (CO) mass flows. The simulation results showed that the operation with coal gave the highest temperature and heat flux, followed by wood chips and bark. On the other hand, the operation with biomass releases fewer gas emissions, CO2 and CO, than those of the operation with coal. The type and proportion of boiler fuel can be easily determined using two methods: predictive equation and ternary contour plot graph, which can be likened to the digital twin of biomass/coal co-firing boiler.

Application of a Simplex-Centroid Mixture Design to Evaluate the Phenolic Compound Content and Antioxidant Potential of Plants Grown in Mexico.

Nowadays, the food and health industries are generating new products with antioxidant potential; among them are those rich in phenolic compounds that have a beneficial impact on human health. Therefore, the aim of this research was to obtain different types of mixtures from Portulaca oleraceae (P), Chenopodium album (C), Opuntia oligacantha Förster var. Ulapa (O), and Amaranthus tricolor (A) and evaluate the content of total phenols, total flavonoids, and antioxidant potential in order to select the mixture with the highest content of phenolic compounds. An experimental simplex-centroid mixture design with 15 experimental treatments was used; the data were analyzed and adjusted to a quadratic model that allowed for the prediction of the content of phenols, flavonoids, and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) of different experimental mixtures. The results show that the individual components of C and P had the highest content of phenols and antioxidant potential. It was observed that the binary mixtures P-C and P-A presented values of total phenols greater than 11 mg of gallic acid equivalents g-1 DW and values of flavonoids greater than 13 mg of quercetin equivalents g-1 DW. These values were higher than those found in the individual components. The P-C mixture with an antioxidant potential of 66.0 ± 0.07 Trolox equivalents g-1 DW could be used as an additive in food or to obtain a functional food that improves the intake of antioxidant compounds in the population.

Combination of sweet orange, lentisk and lemon eucalyptus essential oils: Optimization of a new complete antimicrobial formulation using a mixture design methodology

Sweet orange (Citrus × sinensis (L.) Osbeck), lentisk (Pistacia lentiscus L.) and lemon eucalyptus (Eucalyptus citriodora Hook) are medicinal plants known by its culinary virtues. Their volatile oils have demonstrated promising antimicrobial activity against a panel of microbial strains, including those implicated in food deterioration. In this exploratory investigation, we aimed to determine the antimicrobial formulation of sweet orange, lentisk and lemon eucalyptus essential oils (EOs) using the simplex–centroid mixture design approach coupled with a broth microdilution method. EOs were first extracted by hydrodistillation, and then their phytochemical profile was characterized using Gas chromatography–mass spectrometry (GC-MS). GC-MS analysis identified d-limonene (14.27%), careen-3 (14.11%), β-myrcene (12.53%) as main components of lentisk EOs, while lemon eucalyptus was dominated by citronellal (39.40%), β-citronellol (16.39%) and 1,8-cineole (9.22%). For sweet orange EOs, d-limonene (87.22%) was the principal compound. The three EOs exhibited promising antimicrobial potential against various microorganisms. Lemon eucalyptus and sweet orange EO showed high activity against most tested microorganisms, while lentisk EO exerted important effect against some microbes but only moderate activity against others. The optimization formulations of antimicrobial potential showed interesting synergistic effects between three EOs. The best combinations predicted on C. albicans, S. aureus, E. coli, S. enterica and B. cereus correspond to 44%/55%/0%, 54%/16%/28%, 43%/22%/33%, 45%/17%/36% and 36%/30%/32% of Citrus sinensis, Pistacia lentiscus and Eucalyptus citriodora EOs, respectively. These findings suggest that the combination of EOs could be used as natural food preservatives and antimicrobial agents. However, further studies are needed to determine the mechanisms of action and efficacy of these EOs against different microorganisms.

Development and characterization of self-micro emulsifying drug delivery system of cilnidipine using simplex centroid mixture design

Objective: The main objective of the current research work was development and characterization of self-micro emulsifying drug delivery system of cilnidipine which is poorly water soluble drug. The improved solubility could offer improved dissolution as well as oral bioavailability. Method: Component excipients were selected based on the preliminary studies, capryol 90 and triacetin (1:1) selected as an oil, tween 80 selected as surfactant, transcutol p selected as co-surfactant based on the maximum solubility and better emulsification efficiency. The ternary phase diagram was constructed to identify the optimum composition of the formulation. Simplex centroid mixture design was applied for selection of optimized batch of SMEDDS. Capryol 90 and triacetin, tween 80 and transcutol p were taken as an independent variables X1, X2 &amp; X3 respectively, while emulsification time (Y1) and % drug release at 2 minute (Y2) were taken as dependent variables. Optimized SMEDDS was evaluated based on % transmittance, emulsification time, globule size, PDI, % drug release, and cloud point. After that, SMEDDS were filled in capsule and short term stability study was done and SMEDDS compared with pure drug for dissolution profile. Result and discussion: Optimized batch containing capryol 90 and triacetin (1:1), tween 80 and transcutol p at a concentration of 10%, 67% and 23% respectively. The solubility of cilnidipine is increased by using capryol 90 and triacetin (1:1) as an oily phase. All the evaluation parameters of the optimized SMEDDS were met the acceptance criteria. Optimized batch of SMEDDS showed &gt; 90% drug release within 2 minutes. Dissolution was improved as compared to the pure drug. Conclusion: A self-micro emulsifying drug delivery system of cilnidipine was developed successfully. Present work demonstrated for improving the dissolution of cilnidipine. This may lead to improved oral bioavailability of cilnidipine for the treatment of hypertension.

Combination of Chemically-Characterized Essential Oils from Eucalyptus polybractea, Ormenis mixta, and Lavandula burnatii: Optimization of a New Complete Antibacterial Formulation Using Simplex-Centroid Mixture Design.

This study aims to identify the volatile profile of three essential oils obtained from Eucalyptus polybractea cryptonifera (EPEO), Ormenis mixta (OMEO), and Lavandula burnatii briquet (LBEO) and to examine their combined antibacterial activity that affords the optimal inhibitory ability against S. aureus and E. coli using simplex-centroid mixture design and checkerboard assay. Essential oils (EOs) were isolated by hydrodistillation and characterized using gas chromatography-mass spectrometry (GC-MS) and gas chromatography coupled with flame-ionization detector (GC-FID). The antibacterial activity was performed using disc diffusion and microdilution assays. The chemical analysis revealed that 1,8-cineole (23.75%), p-cymene (22.47%), and α-pinene (11.20%) and p-menthane-1,8-diol (18.19%), α-pinene (10.81%), and D-germacrene (9.17%) were the main components detected in E. polybractea and O. mixta EOs, respectively. However, L. burnatii EO was mainly represented by linalool (24.40%) and linalyl acetate (18.68%). The EPEO, LBEO, and OMEO had a strong antibacterial effect on S. aureus with minimal inhibitory concentrations (MICs) values ranging from 0.25 to 0.5% (v/v). Furthermore, the combination of 1/2048 MICEPEO + 1/4 MICLBEO showed a synergistic antibacterial effect on S. aureus with a FIC index of 0.25, while the formulation of 1/4 MICEPEO + 1/4 MICOMEO demonstrated an antibacterial synergistic activity on E. coli with a FIC index of 0.5. Moreover, the simplex-centroid mixture design reported that the most effective combinations on E. coli and S. aureus correspond to 32%/28%/40% and 35%/30%/35% of E. polybractea, O. mixta, and L. burnatii, respectively. Presented information highlights the action of antibacterial formulations of these EOs and suggests their potential applications as alternatives to commercialized drugs to contract the development of bacteria causing serious infections and food deterioration.

Implementation of Design of Experiment (DoE) for process development and optimization of biosimilars

Selection of a suitable basal media, feed, feeding strategy and glycan structures has a pivotal role during the process development and optimization of monoclonal antibodies. Instead of using one-factor-at-time approach or classical approach for media and feed selection, a DoE approach was implemented. A Simplex centroid mixture design was applied to identify the suitable media/media combinations by evaluating cell growth and productivity followed by a full factorial design for screening of the best suitable feed that enhanced the productivity. Optimization of the process was performed using Response surface methodology with central composite design to determine the optimum interaction between the selected media and feeds. Statistically designed experiments were performed to determine the factors influencing glycan. Uridine, MnCl2 and galactose were added as per the factorial design for evaluating their effect on modulating glycosylation. Prediction of the best combination was made with the maximum response titer by Design-Expert software 12.0. A threefold increase in titer (1909 mg/L) and significant improvement in glycosylation were obtained by statistical approach.

Optimization of total phenolic content, total flavonoid content and anti-gout properties of polyherbal formulation.

An increase in gout prevalence has drawn attention among society and this situation drives the exploration of more favourable treatment using traditional medicinal plants which are rich in phenolic and flavonoid to avoid the side effects of modern medication. However, there are only few studies regarding the optimization of phytochemicals and anti-gout properties of medicinal plants and their combinations. The objectives of this study were to determine the optimal formulation of Strobilanthes crispus, Orthosiphon stamineus Benth and Stevia rebaudiana with maximum total phenolic and flavonoid contents as well as minimum IC50 of invitro xanthine oxidase inhibitory activity and to examine their correlations among the formulations. Plant extracts from hot water infusion were tested for the total phenolic content, total flavonoid content and enzyme inhibition through Folin-ciocalteu assay, aluminium chloride method and xanthine oxidase inhibition assay, respectively. Simplex-centroid mixture design was applied in this study and 13 polyherbal formulations were generated by Design Expert Software. Linear, special cubic and quadratic models were selected to describe the interaction effect between polyherbal formulations and their responses. Low IC50 value (13.90 μg/mL) of xanthine oxidase activity was found in the binary combination of O.stamineus and S.rebaudiana and this probably related to its high phenolic and flavonoid contents as xanthine oxidase inhibition and phytochemicals were correlated. The suggested optimal formulation was comprised of 44.26 % O.stamineus and 55.74 % S.rebaudiana and it could be developed as an alternative treatment for gout.

Multivariate optimization of a green procedure for determination of emerging polycyclic aromatic nitrogen heterocycles in PM2.5 from sites with different characteristics.

Emerging polycyclic aromatic nitrogen heterocycles (PANHs) contributes significantly to the health risk associated with inhaling polluted air. However, there is a lack of analytical methods with the needed performance to their determination. This study presents the optimization and validation for the first time of a green microscale extraction procedure for the determination of twenty-one PANHs, including carbazole, indole, and quinolone classes, in particulate matter (PM2.5) samples by gas chromatography-mass spectrometry. A simplex-centroid mixture design and full factorial design (23) were employed to optimize the following extraction parameters: type and volume of solvent, sample size, extraction time, and necessity of a cleanup step. Low limits of detection and quantification (LOD < 0.97pgm-3 and LOQ < 3.24pgm-3, respectively) were obtained in terms of matrix-matched calibration. The accuracy and precision of the method were adequate, with recoveries in three levels between 73 to 120% and intraday and interday relative standard deviations from 2.0 to 12.9% and 7.3 to 18.9%, respectively. The green character of the method was evaluated using the Analytical Greenness (AGREE) tool, where a score of 0.69 was obtained, indicating a great green procedure. The method was applied to PM2.5 samples collected from sites with different characteristics; the concentrations ranged from 69.3pgm-3 (2-methylcarbazole) to 11,874pgm-3 (carbazole) for individual PANHs and from 2306 to 24,530pgm-3 for ∑21PANHs. Principal component analysis (PCA) and hierarchical clustering enabled discrimination of the sampling sites according to the PANHs concentrations. The score plots formed two distinct groups, one with samples containing higher concentrations of PANHs, corresponding to sites with a major influence from diesel emissions, and another group with minor PANH contents, corresponding to sites impacted by emissions from urban traffic and industrial activities.

Mixture of whey-milk and palm sap for novel kefir beverage using simplex-centroid mixture design

Kefir is a fermented milk beverage with potential health benefits due to its antioxidant, antimicrobial, and anti-diabetic effects. This study aimed to optimize the formulation of a probiotic kefir beverage made with cheese whey, milk, and palm sap using the simplex-centroid mixture design method (SCMD). Microbial count, physicochemical characteristics, and acceptability were evaluated. The optimized formulation contained 16.6% (w/v) cheese whey, 78.6% (w/v) palm sap, and 4.8% (w/v) milk, and showed high antioxidant activity (by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) and acceptable sensory properties (based on a preference scale of 1–9). This study confirms the potential of palm sap in the formulation of novel kefir beverages as a source of probiotics.

Quantification of polycyclic aromatic sulfur heterocycles in fine airborne urban particles (PM2.5) after multivariate optimization of a green procedure

Polycyclic aromatic sulfur heterocycles (PASHs), such as benzothiophenes (BT), dibenzothiophenes (DBT) and benzonapthothiophenes (BNT), can be emitted from vehicular traffic and deposited in fine particles matter (PM2.5). The presence of these compounds in PM2.5 is an environmental concern due to air pollution and its toxic properties. In this study, a green microscale solid–liquid extraction method was developed to determine twenty-three PASHs in PM2.5. A simplex-centroid mixture design was applied to optimize the extraction solvent. A full factorial design was used for preliminary evaluation of the factors that influence the extraction process (extraction time, sample size, and solvent volume) and then a Doehlert design for the significant parameters. The optimal extraction conditions based on the experimental design were: sample size, 4.15 cm2; 450 μL of toluene:dichloromethane (80:20,v/v); and extraction duration, 24 min. High sensitivity (LOD < 0.66pg m−3 and LOQ < 2.21 pg m−3) and acceptable recovery (82.8–120 %), and precision (RSD 3.6–14.0 %) were obtained. The greenness of the method was demonstrated using the Analytical GREEnness (AGREE) tool. The method was applied for analyzing PASHs in PM2.5 samples collected in three time intervals per day from years with different sulfur contents in the diesel: S-500 (≤500 ppm sulfur) and S-50 (≤50 ppm sulfur). Fourteen PASHs were quantified with the highest concentrations observed for 2,8-DMDBT and 4,6-DMDBT, which are recalcitrant compounds. The ANOVA test indicated significant differences between sampling periods during the day. The reduction of diesel S-500 to S-50 corresponded to a 28 % decrease in the total sum of PASHs (∑PASHs) evaluated. Spearman's rank correlations allowed for verifying that BTs and DBTs were highly correlated, suggesting that they were derived from similar sources. A weak correlation of 2,1-BNT and 2,3-BNT with BTs and DBTs indicates that these compounds are a chemical proxy for the emission of diesel engines during the combustion process.

Green and fast ultrasound-assisted extraction procedures for Fe, Mn, Mg and Ca analysis in cane syrups by FAAS

New methodologies for the analysis of Fe, Mn, Mg, and Ca content in cane syrups using FAAS combined with ultrasound-assisted extraction (UAE) were developed and validated. For multivariate optimization of UAE, a simplex-centroid mixture design and individual desirability functions were applied to achieve the best composition of extraction solvents (HNO3, HCl, and water). Under optimal conditions of ultrasound-assisted extraction (100 W, 37 kHz, 10 min, 5.0 mL of extraction solvent (ultrapure water for Fe and Mn and HNO3:H2O (75:25%, v/v), corresponding to a 1.19 mol L−1 HNO3 solution for Mg and Ca)), method validation showed good linearity, confirmed by regression analysis, and low LOD and LOQ values of 0.266–0.284 μg g−1 and 0.114–0.861 μg g−1. Estimates of repeatability and mean precision (RSD = 0.44–2.11%), Horrat values (0.07–0.26), and assessment of trueness by comparing sample preparation methods using a paired t-test demonstrated the excellent precision and trueness of the developed methods. The methods were applied to twenty-five cane syrup samples, and the results of the multivariate analysis showed that the metal ions can be used as indicators of geographical origin or contamination during manufacturing or processing, thus helping to ensure the food quality and safety of this sweetener.

Analysis of Antioxidant Constituents of Filtering Infusions from Oak (Quercus sideroxyla Bonpl. and Quercus eduardii Trel.) and Yerbaniz (Tagetes lucida (Sweet) Voss) as Monoamine Oxidase Inhibitors.

The antioxidant constituents of ancestral products with ethnobotanical backgrounds are candidates for the study of filtering infusions to aid in pharmacotherapies focused on the treatment of depression and anxiety. Monoamine oxidase A (MAO-A) is an enzyme that regulates the metabolic breakdown of serotonin and noradrenaline in the nervous system. The goal of this study was to evaluate in vitro and in silico the effect of antioxidant constituents of filtering infusions from yerbaniz (Tagetes lucida (Sweet) Voss) and oak (Quercus sideroxyla Bonpl. and Quercus eduardii Trel.) as monoamine oxidase inhibitors. Materials were dried, ground, and mixed according to a simplex-centroid mixture design for obtaining infusions. Differential analysis of the phenolic constituent's ratio in the different infusions indicates that among the main compounds contributing to MAO-A inhibition are the gallic, chlorogenic, quinic, and shikimic acids, quercetin glucuronide and some glycosylated derivatives of ellagic acid and ellagic acid methyl ether. Infusions of Q. sideroxyla Bonpl. leaves, because of their content (99.45 ± 5.17 µg/mg) and synergy between these constituents for MAO-A inhibition (52.82 ± 3.20%), have the potential to treat depression and anxiety. Therefore, future studies with pharmacological approaches are needed to validate them as therapeutic agents with applications in mental health care.