Mixture Experimental Design Research Articles

Enzymatic treatment improves the antioxidant and antiproliferative activities of Adenanthera pavonina L. seeds

Abstract We evaluated the effect of enzymatic treatment by amylase, cellulase and protease on antioxidant and antiproliferative activities of Adenanthera pavonina L. seeds. The effect was evaluated by using an experimental mixture design. The results showed that the antioxidant activity of the seeds increased after the enzymatic treatment. The enzymatic treatment using protease and cellulase (1:1, v/v) showed the highest values of antioxidant activity due to the increase of phenolic compounds content, mainly phenolic acids. The antiproliferative activity of the extract obtained by optimum enzymatic treatment was evaluated. We found the antiproliferative activity against the tumour lineage of prostate (PC-3) and kidney (786–0) was improved after enzymatic treatment. This work provides information that may be useful in handling of functional foods and/or drugs, since the functional properties of seeds such as antioxidant and antitumor activities were improved by enzymatic treatment with protease and cellulase.

OPTIMIZATION OF SELF-NANOEMULSIFYING DRUG DELIVERY SYSTEMS OF LEMONGRASS (CYMBOPOGON CITRATUS) ESSENTIAL OIL

Objective: Focus of this study was to optimize and to characterize the self-Nano emulsifying drug delivery system using lemongrass (Cymbopogon citratus) essential oil.Methods: The optimum formulas were analyzed using a D-Optimal mixture experimental design and performed using a Design Expert® Ver. 7.1.5. Formulation variables which include in the design were: oil component X1 (a mixture of Cymbopogon citratus essential oil and virgin coconut oil/VCO), surfactant X2 (Tween 80), and co-surfactant (PEG 400), while emulsification time in a sec (Y1) and transmittance in percent (Y2) as responses.Results: The optimum formula for SNEDDS in the current study were: Cymbopogon citratus essential oil (7.147%), VCO (7.147%), Tween 80 (71.417%), and PEG 400 (14.290%). From the optimizing formula can be shown that the mean of droplet size, polydispersity-index, zeta potential, and viscosity were: 13.17±0.06 nm, 0.17±0.05,-20.90±1.47 mV, 200±0mPa. s (n=3), respectively. Furthermore, the optimized formula has passed the thermodynamic stability test; meanwhile, transmission electron microscopy displayed spherical shape.Conclusion: The optimized SNEDDS formula was improving solubility of poorly soluble Cymbopogon citratus essential oil.

Optimization and Characterization of Palm Oil-based Nanoemulsion Loaded with Parthenium hysterophorus Crude Extract for Natural Herbicide Formulation.

The present study revealed the optimization of nanoemulsion containing palm oil derivatives and Parthenium hysterophorus L. crude extract (PHCE) as pre-emergence herbicide formulation against Diodia ocimifolia. The nanoemulsion formulation was prepared by high energy emulsification method, and it was optimized by mixture experimental design (MED). From the optimization process, analysis of variance (ANOVA) showed a fit quadratic polynomial model with an optimal formulation composition containing 30.91% of palm kernel oil ester (PKOE), 28.48% of mixed surfactants (Tensiofix and Tween 80, 8:2), 28.32% of water and 12.29% of PHCE. The reading of both experimental and predicted particle size in the verification experiment were acceptable with a residual standard error (RSE) was less than 2%. Under the optimal condition, the smallest particle size obtained was 140.10 nm, and the particle was shown by morphology analysis to be spherical and demonstrated good stability (no phase separation) under centrifugation and different storage conditions (25 ± 5°C and 45°C). Nanoemulsion stored for 60 days exhibits monodisperse emulsion with a slight increase of particle size. The increase in particle size over time might have contributed by Ostwald ripening phenomenon which is shown by a linear graph from Ostwald ripening rate analysis. In the in vitro germination test, P. hysterophorus nanoemulsion (PHNE) was shown to cause total inhibition of D. ocimifolia seed at lower concentration (5 g L-1) as compared to PHCE (10 g L-1). The finding of the research could potentially serve as a platform for the development of palm oil based formulation containing plant crude extract for green weed management.

Optimizing the Extraction of Anthocyanins from the Skin and Phenolic Compounds from the Seed of Jabuticaba Fruits (Myrciaria jabuticaba (Vell.) O. Berg) with Ternary Mixture Experimental Designs

Total phenolic compounds (TPC) extraction from the seed and total monomeric anthocyanins (TMA) extraction from the skin of “Sabara” jabuticaba were optimized with simplex lattice designs for solvent mixing, and the extraction time was optimized by univariate design. The optimum conditions for the extraction method were ethanol:water (60:40 v/v) solvent for TPC (seed) and methanol:water:acetic acid (80:20:0.5 v/v/v) solvent for TMA (skin). For both compound groups, the optimum extraction time was 30 min. The TMA yield for the skin of the “Sabara” variety was 1172.16 mg cyanidin-3-glycoside equivalents per 100 g freeze-dried sample, and for TPC in the seed, it was 86.50 mg gallic acid equivalents per 1 g freeze-dried sample. Both optimized extraction protocols proved to be extremely fast, simple, inexpensive and to have excellent extraction performance. The optimized protocols were compared with two other methods described in the literature and they were also applied to study the TMA contents in skin and the TPC contents in seed of five other varieties of jabuticaba, harvested in 2014 and 2015.

Developing a space-filling mixture experiment design when the components are subject to linear and nonlinear constraints

This article presents a case study of developing a space-filling design (SFD) for a constrained mixture experiment when the experimental region is specified by single-component constraints (SCCs), linear multiple-component constraints (LMCCs), and nonlinear multiple-component constraints (NMCCs). Traditional methods and software for designing constrained mixture experiments with SCCs and LMCCs (using either optimal design or SFD approaches) are not directly applicable because of the NMCCs. A SFD algorithm in the JMP® software was modified to accommodate the NMCCs; the modification is described in this article. The case study involves high-level waste (HLW) glass that is subject to the formation of nepheline crystals as the glass cools. This can significantly reduce the durability of HLW glass (which is undesirable). The goal of the study was to develop a SFD for the HLW glass compositional region where nepheline may form, and generate data for modeling nepheline formation as a function of HLW glass composition. The HLW glass composition region was specified in terms of eight components with SCCs, two LMCCs, and two NMCCs. The NMCCs were based on a nonlinear logistic regression model for a binary nepheline response that was developed from previous data. This article discusses the HLW glass example, the constraints specifying the experimental composition region, and how an existing algorithm for generating SFDs was modified to accommodate the NMCCs. The methodology discussed in this article can be applied to any example in which the experimental region is specified by one or more nonlinear constraints in addition to linear constraints on mixture components and/or non-mixture variables.

Mixture Design of Experiments for the Optimization of Carbon Source for Promoting Undecylprodigiosin and Actinorhodin Production

Mixture Design of Experiments for the Optimization of Carbon Source for Promoting Undecylprodigiosin and Actinorhodin Production

Mixed Waste Combustion Test Research and Calculation of Activation Energy

Thermo gravimetric combustion experiments [1] of the easy chopsticks, food bags, cotton and its mixed components were investigated, by the mixture experiment design program [2]. Then combustion characteristics curves of thermo gravimetric and thermo gravimetric differential, and each group point average activation energy [3] were obtained. Base on the average activation energy of each waste component combustion, the activation energy calculation empirical correlation which fits in various mixed waste combustion calculation can be set up through three Scheffe polynomials. In addition to the three vertices of the gravity method, which were used to conduct the mixed waste combustion test, and the results of mixed waste activation energy agree well with the activation energy calculated from the empirical correlation. Thus, the activation energy is correct. Application of this method plays an important role in the direction for the design of waste incinerator actually [4] and the waste combustion adjustment.

Experiments with mixtures

The designs for mixture experiments have been extensively used in agricultural/ industrial experiments. Some of the situations in which these designs could be advantageously used are: split application of fertilizers, intercropping experiments where the interest of experimenter is to find best crop mixtures, sensory evaluation experiments for making the agricultural and animal products, preparation of fertilizers, insecticides/ pesticides mixtures for optimum response, feeding trials in animal nutritional experiments. Mixture experiments can be used in with unrestricted region, with restricted region having upper and/or lower bounds, with process variable(s).

Experimental and Modeling Study on the Curing Properties of Natural Rubber Composites Filled with Varying Proportions of Carbon Black, Modified Bentonite and Raw Bentonite

The aim of this study was to investigate the effect of replacing carbon black (CB) with inexpensive and environmentally friendly fillers – bentonite (BNT) and modified bentonite (M-BNT), on the curing properties of natural rubber (NR) composites. A control sample (unfilled NR) and thirteen NR composites filled with varied proportions of CB (x1), M-BNT (x2), and BNT (x3) based on a third degree – simplex lattice mixture design of experiment (DOE) were prepared in this study. Rheometric results showed that 33% substitution of CB with M-BNT provides the highest elastic torque values. Mixture of 10phr CB and 5phr M-BNT (CB/M-BNT/BNT 10/5/0) produces synergistic effect on curing. The presence of CB increases vulcanization rate due to its high basicity and low oxygen content while M-BNT serves as vulcanizing accelerator due to the present amine groups. Coefficients of reduced hierarchical models showed that the main factors contributed mainly on the curing parameters: β1 for the torque values, β2 for the scorch and curing time, and β3 for CRI. High values of coefficient of determination (r2) were computed particularly for MH (98.20%), ΔS (99.13%), ts2(95.68%), tc90(95.70%) and CRI (95.97%) establishing best fit between the model and experimental values.

Reduction of βN-alkanoyl-5-hydroxytryptamides and diterpenes by yeast supplementation to green coffee during wet processing

Coffee is one of the most consumed non-alcoholic beverages in the world. It is well known that some compounds present in coffee beans have important biological activities. In this study, evidence was turned to βN-alkanoyl-5-hydroxytryptamides (C-5HTs) and to the furokaurane diterpenes cafestol and kahweol, associated with gastric irritation and increasing of blood cholesterol, respectively. Fermentation in coffee post-harvest wet process was induced by three Saccharomyces cerevisiae yeasts (for bakery, white and sparkling wines) as starter cultures. Variations in mass, time, temperature and pH (56 experiments under fractional factorial and mixture experimental designs) were tested. Substantial reductions for C-5HTs (up to 38% reduction for C20-5HT and 26% for C22-5HT) as well as for diterpenes (54% for cafestol and 53% for kahweol) were obtained after treating green coffee beans with 0.6 g of a 1:1:1 mixture the three yeasts for 12 h at 15 °C and pH 4. Caffeine and 5-CQA content, monitored in the green coffee beans, did not change. Therefore, the use of starter cultures during coffee post-harvest wet process has influence on the amount of some important compounds related to health and improves the sensory quality of the beverage.

Development of a kojic monooleate-enriched oil-in-water nanoemulsion as a potential carrier for hyperpigmentation treatment

IntroductionKojic monooleate (KMO) is an ester derived from a fungal metabolite of kojic acid with monounsaturated fatty acid, oleic acid, which contains tyrosinase inhibitor to treat skin disorders such as hyperpigmentation. In this study, KMO was formulated in an oil-in-water nanoemulsion as a carrier for better penetration into the skin.MethodsThe nanoemulsion was prepared by using high and low energy emulsification technique. D-optimal mixture experimental design was generated as a tool for optimizing the composition of nanoemulsions suitable for topical delivery systems. Effects of formulation variables including KMO (2.0%–10.0% w/w), mixture of castor oil (CO):lemon essential oil (LO; 9:1) (1.0%–5.0% w/w), Tween 80 (1.0%–4.0% w/w), xanthan gum (0.5%–1.5% w/w), and deionized water (78.8%–94.8% w/w), on droplet size as a response were determined.ResultsAnalysis of variance showed that the fitness of the quadratic polynomial fits the experimental data with F-value (2,479.87), a low P-value (P<0.0001), and a nonsignificant lack of fit. The optimized formulation of KMO-enriched nanoemulsion with desirable criteria was KMO (10.0% w/w), Tween 80 (3.19% w/w), CO:LO (3.74% w/w), xanthan gum (0.70% w/w), and deionized water (81.68% w/w). This optimum formulation showed good agreement between the actual droplet size (110.01 nm) and the predicted droplet size (111.73 nm) with a residual standard error <2.0%. The optimized formulation with pH values (6.28) showed high conductivity (1,492.00 µScm−1) and remained stable under accelerated stability study during storage at 4°C, 25°C, and 45°C for 90 days, centrifugal force as well as freeze–thaw cycles. Rheology measurement justified that the optimized formulation was more elastic (shear thinning and pseudo-plastic properties) rather than demonstrating viscous characteristics. In vitro cytotoxicity of the optimized KMO formulation and KMO oil showed that IC50 (50% inhibition of cell viability) value was >100 µg/mL.ConclusionThe survival rate of 3T3 cell on KMO formulation (54.76%) was found to be higher compared to KMO oil (53.37%) without any toxicity sign. This proved that the KMO formulation was less toxic and can be applied for cosmeceutical applications.

Optimal combination of multiple cryoprotectants and freezing-thawing conditions for high lactobacilli survival rate during freezing and frozen storage

The optimal cryoprotectants combination, freezing rate and thawing temperature were investigated for preserving Lactobacillus plantarum and Lactobacillus casei during freezing and frozen storage. It is indicated that, among all cryoprotectants applied singly, 150 g/L and 100 g/L sucrose provided the best protective effect for L. plantarum and L. casei, respectively (survival rate = 74.4% and 84.8%, respectively). By using orthogonal experimental design for cryoprotectant mixtures, the mixture of trehalose, sucrose, glycerol and skimmed milk at final concentration of 12.5, 12.5, 37.5 and 25.0 g/L, respectively, appeared to enhance significantly the survival rate of L. plantarum (92.8%) and L. casei (91.2%). Among all freezing and thawing conditions examined, the survival rate of L. plantarum was the highest at a freezing rate of −10 °C/min and thawing temperature of 0 °C; and that of L. casei, at a freezing rate of −1 °C/min and thawing temperature of 0 °C. The cryoprotectant effect exerted by keeping the integrity of cell membrane and therefore maintaining the lactobacilli survival.

Weighted A-optimality criterion for generating robust mixture designs

Abstract Many experiments in research and development of industrial product formulations involve mixtures of ingredients. These are experiments in which the experimental factors are the ingredients of a mixture and the proportion of mixture ingredients cannot be varied independently. Mixture experiments usually involve constraints on the ingredient proportions of the mixture. In this paper, we propose a technique to generate robust A-optimal designs for mixture experiments using a genetic algorithm where the experimental region is an irregularly-shaped polyhedral region formed by constraints on the mixture ingredient proportions. Our approach seeks the design which minimizes the weighted average of the sum of the variances of the estimated coefficients across a set of potential mixture models that may occur due to initial model misspecification. This technique provides an alternative approach when the experimenter is uncertain about which final model should be selected. For illustration, examples with three ingredients are presented with comparisons of our GA designs to those obtained using PROC OPTEX that focuses only on a single model.

Parsing in vivo and in vitro contributions to microcrystalline cellulose hydrolysis by multidomain glycoside hydrolases in the Caldicellulosiruptor bescii secretome

Six multidomain glycoside hydrolases (GHs), CelA (Athe_1867), CelB (Athe_1859), CelC (Athe_1857), CelD (Athe_1866), CelE (Athe_1865), and CelF (Athe_1860) are encoded in the Caldicellulosiruptor bescii glucan degradation locus (GDL). Each GH was affinity-tagged, overexpressed, and purified from recombinant C. bescii for side-by-side characterization in vitro and to examine the contribution of each of these enzymes to microcrystalline cellulose hydrolysis in vivo. All six recombinant GDL GHs were glycosylated, and deletion of glycosyltransferase Athe_1864 eliminated this posttranslational modification. A simplex centroid mixture experimental design revealed that in vitro optimal mixtures of the GDL GHs were predominantly CelA, CelC, and CelE, had low to moderate proportions of CelB and CelD, and minimal CelF. The best binary mixture contained CelA + CelB in a 3:2 molar ratio, whereas the best ternary mixture was composed of CelA + CelC + CelE in equimolar amounts. Neither the native C. bescii secretome nor cocktails of GDL GHs in vitro exceeded 25% of cellulose hydrolysis observed for wild-type C. bescii in vivo. C. bescii deletion strains lacking specific GDL GHs could be restored to wild-type degradation levels with the exogenous addition of either 5 µg/ml of recombinant GDL GH cocktails based on the natural secretome or mixtures optimized in vitro. Also, the addition of CelA up to 100 µg/ml provided no significant additional benefit. These results suggest that the C. bescii secretome is naturally balanced to achieve optimal synergy for cellulose degradation. They also reinforce the importance of microbial contributions to microcrystalline cellulose hydrolysis and suggest that mass action effects from glucan fermentation shift equilibria to drive degradation.

Simultaneous determination of the size and concentration of AgNPs in water samples by UV–vis spectrophotometry and chemometrics tools

The combination of UV–vis spectrophotometry with a chemometric calibration tool based on partial least squares (PLS) has allowed us the development of a multivariate analytical method that simultaneously estimates the concentration and size of mixtures of silver nanoparticles (AgNPs) in environmental water samples. The method is based on changes in the surface plasmon resonance band (SPRB) of AgNPs when they form aggregated/assembled structures with L-cysteine (L-cys). Measurementts were performed by employed a fixed-time kinetics method that implies that the final spectra (response) are obtained by subtstracting the solutions spectra at fixed times. Optimization of experimental conditions affecting aggregation such as time, temperature, pH and concentration of aggregating substance was performed by experimental design and response surface methodologies (RSM). A multivariate calibration model using AgNPs of known diameter size ((20 ± 3), (41 ± 3), (59 ± 5) and (79 ± 7) nm) within a concentration range between 0.62 and 2.5 mg L−1 was constructed by using a mixture experimental design and PLS. The method was finally applied to estimate size and concentration of AgNPs in AgNPs-spiked river and tap water samples. Water samples were spiked with individual, binary and ternary mixtures of AgNPs of different sizes and by using two types of AgNPs: citrate-coated AgNPs (cit-AgNPs) and polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs). A good correspondence was obtained between predicted values and the total amount of AgNPs added with recovery values ranged within 80–160% for the individual mixtures, 68–108% for the binary mixtures and 60–64% for the ternary mixtures of AgNPs. Finally, transmission electron microscopy (TEM) measurements were performed for those cases where discrepancies between the expected and the obtained values were observed. TEM micrographs evidenced the presence of agglomerates or aggregates of AgNPs in some of the mixtures or water tested.

Ethanol production from hemicellulose by a consortium of different genetically-modified sacharomyces cerevisiae

Abstract In this study, Saccharomyces cerevisiae was engineered to degrade and utilize xylan, one of the major polysaccharide chains present in hemicellulose. Different hemicellulases from Trichoderma reesei, namely: endoxylanase, β-xylosidase, acetylxylan esterase, α- d -glucuronidase and α- l -arabinofuranosidase, were heterologously secreted by S. cerevisiae. A mixture experimental design was adapted to statistically describe the synergistic interactions between the hemicellulases and to determine the optimum formulations for the hydrolysis of xylan substrates. The hydrolytic activities of the hemicellulase mixtures were then improved by displaying the hemicellulases on the yeast surface as whole-cell biocatalysts. The engineered yeast strains displaying hemicellulases were further engineered to express xylose-utilization genes xylose isomerase (XI) and xylulokinase (XK) which enable its utilization of xylose as a sole carbon source. The resulting consortium was then able to grow and produce ethanol from different xylan substrates.

Evaluation of Spironolactone Solid Dispersions Prepared by Co-Spray Drying With Soluplus® and Polyvinylpyrrolidone and Influence of Tableting on Drug Release

Solid dispersions of spironolactone with Soluplus® and polyvinylpyrrolidone were prepared by spray drying according to a mixture experimental design and evaluated for moisture content, particle size, drug solubility, crystallinity (powder X-ray diffraction and differential scanning calorimetry), and physicochemical interactions (Fourier-transform infrared spectroscopy, Raman). In vitro dissolution was evaluated for the spray dried product itself and after compression into tablets, and prediction models were derived using multiple linear regression analysis. The spray dried products consisted of amorphous drug, indicated by the absence of crystalline powder X-ray diffraction peaks. Amorphization and interactions impacted changes in the Fourier-transform infrared spectroscopy spectra in the ranges 2900-3000 cm−1 (C-H) and 1600-1800 cm−1 (C=O) and caused merging at 1690 cm−1 (C=O of lactone) and 1670 cm−1 (C=O of thioacetyl group). In the Raman spectra, amorphization and interactions resulted in disappearance of peak at 1690 cm−1 (C=O) and merging of peaks at 582 and 600 cm−1 (C-S). Hydrogen bonding between the thioacetyl group of the drug with the hydroxyl groups of Soluplus® caused marked suppression of the peak at 1190 cm−1 (R-C(=O)-S vibration). Amorphization and interactions resulted in improved solubility and dissolution which was greatest for drug/Soluplus® ratio 1:4 and was also demonstrated in the corresponding tablets.

Physicochemical and nutritional characterization of sweet snacks formulated with Prosopis alba flour

Prosopis alba flour (PAF) is an adequate ingredient for preparing gluten-free sweet snacks of high nutritional value. Therefore, the objective of this work was to use this flour, together with sugar and honey, as agglutinant agent in the elaboration and functional characterization of sweet snacks. Snacks were formulated with ancestral American seeds (22% amaranth, 22% quinoa, 7.8% quinoa) and variable amounts of each of the three agglutinants (48.2% total) according to an experimental design for mixtures with the restriction of non using only PAF as agglutinant. Five formulations were obtained and characterized by color, moisture, water activity and texture parameters. Sensorial attributes of the two best snacks selected by a test of preference (A and E), were determined using a 9 points hedonic scale. Snacks with sugar or sugar from PAF presented after heating the major variation of color. Snacks with PAF presented intermediate values of moisture and higher values of consistency, resilience and elasticity. The snack containing equal amounts of each agglutinant (A) presented equivalent sensory attributes as that elaborated only with sugar (E). Concluding, PAF resulted a suitable ingredient along with sugar and honey for sweet snacks destined to celiac people that also resulted well accepted by consumers.

Component optimization of dairy manure vermicompost, straw, and peat in seedling compressed substrates using simplex-centroid design

ABSTRACTVermicomposting is a promising method to disposal dairy manures, and the dairy manure vermicompost (DMV) to replace expensive peat is of high value in the application of seedling compressed substrates. In this research, three main components: DMV, straw, and peat, are conducted in the compressed substrates, and the effect of individual components and the corresponding optimal ratio for the seedling production are significant. To address these issues, the simplex-centroid experimental mixture design is employed, and the cucumber seedling experiment is conducted to evaluate the compressed substrates. Results demonstrated that the mechanical strength and physicochemical properties of compressed substrates for cucumber seedling can be well satisfied with suitable mixture ratio of the components. Moreover, DMV, straw, and peat) could be determined at 0.5917:0.1608:0.2475 when the weight coefficients of the three parameters (shoot length, root dry weight, and aboveground dry weight) were 1:1:1. For different purpose, the optimum ratio can be little changed on the basis of different weight coefficients.Implications: Compressed substrate is lump and has certain mechanical strength, produced by application of mechanical pressure to the seedling substrates. It will not harm seedlings when bedding out the seedlings, since the compressed substrate and seedling are bedded out together. However, there is no one using the vermicompost and agricultural waste components of compressed substrate for vegetable seedling production before. Thus, it is important to understand the effect of individual components to seedling production, and to determine the optimal ratio of components.

Improvement of a mixture experiment model relating the component proportions to the size of nanonized itraconazole particles in extemporary suspensions

A paper by Foglio Bonda et al. published previously in this journal (2016, Vol. 83, pp. 175–183) discussed the use of mixture experiment design and modeling methods to study how the proportions of three components in an extemporaneous oral suspension affected the mean diameter of drug particles (Zave). The three components were itraconazole (ITZ), Tween 20 (TW20), and Methocel® E5 (E5). This commentary addresses some errors and other issues in the previous paper, and also discusses an improved model relating proportions of ITZ, TW20, and E5 to Zave. The improved model contains six of the 10 terms in the full-cubic mixture model, which were selected using a different cross-validation procedure than used in the previous paper. Compared to the four-term model presented in the previous paper, the improved model fit the data better, had excellent cross-validation performance, and the predicted Zave of a validation point was within model uncertainty of the measured value.