Central Composite Rotatable Experimental Design Research Articles

Salt slag and rice husk ash as raw materials in zeolite synthesis: Process optimization using central composite rotational design

The growing demand of zeolites for many industrial applications has led to a search for eco-friendly alternatives for their production, in an attempt to reduce costs, save natural resources and alleviate the associated environmental impacts. In the present study, hazardous aluminum salt slag (aluminum source) and rice husk ash (silicon source) were used as secondary raw materials to synthesize sustainable NaP-type zeolites through a hydrothermal process. A central composite rotational experimental design was applied to evaluate the effect of the reaction time and hydrothermal temperature on the obtained zeolites crystallinity. Using the proposed experimental design, temperatures between 85 and 115 °C and different reaction times (2–28 h) were tested. It was found that the interaction between the variables (time and temperature) and both variables, independently, exerted a significant influence on the crystallinity of the zeolites. The optimal experimental conditions (105 °C and 20 h), statistically determined, enabled a high degree of crystallinity (>73%) to be achieved. Thus, the use of hazardous aluminum and agri-food wastes as unconventional precursors for the production of zeolites represents a sustainable alternative to manage these wastes, by transforming them into secondary raw materials.

Optimization of fermentation medium components by response surface methodology (RSM) and artificial neural network hybrid with genetic algorithm (ANN-GA) for lipase production by Burkholderia cenocepacia ST8 using used automotive engine oil as substrate

Bioconversion of used automotive engine oil (UEO) into lipase was conducted via submerged fermentation by Burkholderia cenocepacia ST8, as a strategy for value-added product generation and waste management. Response surface methodology (RSM) and artificial neural network hybrid with genetic algorithm (ANN-GA) were employed to optimize the fermentation medium for enhancing extracellular lipase production by B. cenocepacia ST8. Employing a four-factor-five-level central composite rotatable experimental design (CCRD), a reduced quartic polynomial RSM model and ANN model (4-4-1) trained using Bayesian Regularization were developed to attain the optimized fermentation medium for maximum level of lipase production. The RSM model predicted the following as the optimum media constituents: 2.28% v/v of Tween 80, 2.26% v/v of UEO, 0.79% w/v of nutrient broth, and 1.33% w/v of gum arabic, with an actual lipase yield of 216 U/mL. While, ANN-GA predicted the optimum media constituents to be 3% v/v of Tween 80, 3% v/v of UEO, 0.72% w/v of nutrient broth, and 3.38% w/v of gum arabic, with actual lipase yield of 225 U/mL. In comparison to the unoptimized medium, optimized RSM and ANN-GA systems both demonstrated a 1.6-fold increment in lipase production. Tween 80 and nutrient broth concentrations were the most important variables influencing the lipase production. The findings of this study indicated that the ANN-GA and RSM could be useful for effective optimization of the fermentation medium for enzyme production.

Optimization of Solvent Oil Extraction from Sandbox (Hura crepitans Linn.) Seeds

Due to increasing demand for food, industrial applications and biodiesel production on vegetable oils, optimization of oil extraction processes has become imperative to obtain maximum oil yield from vegetable oil feedstocks. The effect of process factors: moisture content, roasting temperature, and time, extraction temperature, and time on oil yield from sandbox seed by solvent extraction were investigated using a 5 × 5 Central Composite Rotatable (Experimental) Design of Response Surface Methodology. Results obtained were analyzed using Analysis of Variance (ANOVA) and SPSS statistical tool at (p = 0.05). The optimum conditions predicted were validated by experiments. The American Oil Chemists’ Society AOCS 5-04 standard procedure for solvent extraction was used in the experiment. The oil yield from the sandbox seed ranged from 20.9-53.6%, and was increased at the range (6-10%) moisture content, (80-100°C) roasting temperature, (5-15 min) roasting time, (90-100°C) extraction temperature and (90-150 min) extraction time. The optimum oil yield of 53.6% was obtained at the processing conditions of 10.0% moisture content, 95oC roasting temperature, 15 min roasting time, 65oC extraction temperature, and 90 min extraction time. Mathematical models to predict sandbox seed oil yield at varying process conditions were developed with an R2 (0.81). The optimum extractable oil yield of 57.10% was predicted for sandbox seed at processing conditions of 10.25% moisture content, 98.72oC roasting temperature, 17.63 min roasting time, 67.01oC extraction temperature, and 96.6 min extraction time. The study results provide data for equipment and process designs for oil extraction from the sandbox and other oilseeds.

Effect of pulsed electric field parameters on the alkaline extraction of valuable compounds from perilla seed meal and optimization by central composite design approach

Perilla seed meal (PSM) is the by-product of the oil extraction industry and a potential source of bioactive compounds. Pulsed electric field, a non-thermal technology, can be used to recover heat labile bioactive compounds from plant materials such as perilla seed meal. This study found that pulsed electric field (PEF) assisted alkaline extraction influenced the protein content and antioxidant activity of perilla seed meal (PSM). Among all PEF parameters, electric field strength (EFS) and pulse width (PW) were found to be the most significant as judged by F-value. Consequently, a central composite rotatable experimental design was applied to investigate the effect of electric field strength (EFS) and pulse width against protein content, antioxidant activity, and total phenolic content (TPC) of PEF treated PSM extract. Compared to conventional alkaline extraction, an increase in the yield of protein content by 10.58%, antioxidant activity by 7.48%, and total phenolic content by 21.59% was recorded at the optimal values of electric field strength (4 kV/cm) and pulse width (120 µs). Moreover, Karl pearson correlational analysis revealed a strong relationship (linear, R2=0.963) between antioxidant activity and total phenolic content. The validation was done at 95% confidence level for which the predicted values were compared with the actual experimental values, and the means were found to be insignificantly different from each other (p > 0.05). Industrial relevanceNon-thermal extraction techniques such as pulsed electric field used in this study can be used for the recovery of valuable compounds from the food materials especially heat sensitive compounds. PEF treatment increased the extractability of the water-soluble compounds from the perilla seed meal (PSM) samples and increased the recovery of valuable compounds from PSM while maintaining the nutritional and functional viability. Hence, this technology is having the potential to be used as assistant technology for the extraction of heat sensitive components from the plant cells which may find its applications in neutraceutical and pharmaceutical industries.

Optimized removal of hexavalent chromium from water using spent tea leaves treated with ascorbic acid

Spent tea leaves were functionalized with ascorbic acid to obtain treated tea waste (t-TW) to encourage the adsorption of hexavalent chromium from water. The adsorption removal of Cr(VI) was systematically investigated as a function of four experimental factors: pH (2–12), initial Cr(VI) concentration (1–100 mg L−1), t-TW dosage (0–4 g L−1), and temperature (10–50 °C) by following a statistical experimental design. A central composite rotatable experimental design based on a response surface methodology was used to establish an empirical model that assessed the individual and combined effects of factors on adsorptive removal of Cr(VI). The model was experimentally verified and statistically validated then used to predict optimal adsorption removal of Cr(VI) from water. At optimized conditions, ≥ 99% of 1 mg L−1 Cr(VI) can be removed by 4 g L−1 t-TW at a pH of 9. The adsorptive mechanism was assessed by conducting kinetics and equilibrium studies. The adsorption of Cr(VI) by t-TW followed a pseudo-second-order kinetics model (k2 = 0.001 g mg−1 h−1) and could be described by Langmuir and Temkin isotherms, indicating monolayer adsorption and predominantly adsorbate-adsorbent interactions. The t-TW exhibited a competitive Cr(VI) adsorption capacity of 232.2 mg g−1 compared with the other low-cost adsorbents. These results support the utilization of tea waste for the removal of hazardous metal contaminants from aqueous systems.

Phytochemical content and antioxidant activity of extruded products made from yellow corn supplemented with apple pomace powder

The aimed of this study was quantified total phenols content, total flavonoids, and antioxidant activity in extruded ready-to-eat products made from yellow corn added with apple pomace powder. A central composite rotatable experimental design was used. The variables tested were exit die temperature (140-180 °C), feed moisture (14-20 g/100 g) and apple pomace concentration (0-30 g/100 g). The effect of the process variables on the total contents of phenols, flavonols, flavanols and flavonoids and antioxidant activity was evaluated using the response surface methodology. The data of each response were fitted to a second-order model with determination coefficients ≥ 0.71. The extruded product with no added apple bagasse showed the lowest values of the evaluated phytochemicals but had higher antioxidant activity by DPPH. The addition of apple pomace increased the phytochemical content and antioxidant activity in extruded ready-to-eat products made with yellow corn. This makes it possible to obtain a formulation of an extruded food rich in phenolic compounds with potential to contribute to prevention of oxidative stress, while making use of agro-industrial waste from apple juice extraction.

Tensile Strength of Interpulse Gas Tungsten Arc Welded Butt Joints of Nimonic Super Alloy C263

Nimonic C263 a nickel base super-alloy is generally used in the major components particularly in various structural and hottest sections of the gas turbine engine mainly in the combustor, exhaust sections including blades, discs, liners, and casings, etc. The interpulse gas tungsten constricted welding process is a modified controlled heat input arc welding technique. In this experiment response surface, rotatable central composite experimental design is methodically implemented for the evaluation of the impact of the key factors (i.e. interpulse current, weld current, weld speed and background current) on the tensile strength of butt-welded joints. The welded coupons are tested for tensile tests and obtained a maximum of 1152MPa. The outcome of this experimental examination and thorough optimization will be useful in choosing the most appropriate and suitable welding ranges of the above-mentioned factors for interpulse gas tungsten constricted arc welding of Nimonic superalloy C263 for automotive and aerospace applications.

Características físicas, fitoquímicas y sensoriales de cereales para desayuno altos en fibra producidos combinando subproductos de zanahoria con salvado de trigo y avena

High-fiber breakfast cereals are mainly produced by extrusion, and to improve its nutritional/nutraceutical properties, the addition of raw materials rich in bioactive compounds has been suggested. The aim of this study was to evaluate the physical, phytochemical and sensory characteristics of extruded high-fiber breakfast cereals (HFB) prepared from carrot by-products and bran as affected by feed moisture (FM, 19.34–30.66%) and carrot pomace content (CPC, 5.51–22.49%), under a central composite rotatable experimental design. When FM was increased, flexural modulus (FMO, 54-89 MPa), soluble dietary fiber (SDF, 0.64-4.18%), bound phenolic compounds (BPC, 0.02-0.25 mg GAE/g), and DPPH antioxidant activity from BPC extracts (2.07-2.29 µmol TE/g) increased, whereas expansion index (1.09-0.89) diminished. Also, when CPC was elevated, FMO (54-83 MPa), water solubility index (14.21-18.84%), color b* (26.8-28.8), insoluble dietary fiber (19.43-24.71%), SDF (1.12-3.98%), free phenolic (0.56-0.71 mg GAE/g), and flavonoids compounds (0.05-0.31 mg QE/g) increased, whereas BPC decreased (0.25-0.14 mg GAE/g). The HFB presented good (≥ 69%) sensory acceptability. These extruded products presented appropriate physical, phytochemical, and sensory characteristics, whose consumption has potential nutraceutical benefits.

Electrochemical Mineralization of Ibuprofen on BDD Electrodes in an Electrochemical Flow Reactor: Numerical Optimization Approach

Statistical analysis was applied to optimize the electrochemical mineralization of ibuprofen with two boron-doped diamond (BDD) electrodes in a continuous electrochemical flow reactor under recirculation batch mode. A central composite rotatable (CCR) experimental design was used to analyze the effect of initial pH (2.95–13.04), current intensity (2.66–4.34 A), and volumetric flow rate (0.16–1.84 L/min) and further optimized by response surface methodology (RSM) to obtain the maximum mineralization efficiency and the minimum specific energy consumption. A 91.6% mineralization efficiency (EM) of ibuprofen with a specific energy consumption (EC) of 4.36 KW h/g TOC within 7 h of treatment was achieved using the optimized operating parameters (pH0 = 12.29, I = 3.26 A, and Q of 1 L/min). Experimental results of RSM were fitted via a third-degree polynomial regression equation having the performance index determination coefficients (R2) of 0.8658 and 0.8468 for the EM and EC, respectively. The reduced root-mean-square error (RMSE) was 0.1038 and 0.1918 for EM and EC, respectively. This indicates an efficient predictive performance to optimize the operating parameters of the electrochemical flow reactor with desirability of 0.9999993. Besides, it was concluded that the optimized conditions allow to achieve a high percentage of ibuprofen mineralization (91.6%) and a cost of 0.002 USD $/L. Therefore, the assessed process is efficient for wastewater remediation.”

Buriti Oil Emulsions as Affected by Soy Protein Isolate/High-Methoxyl Pectin Ratio, Oil Content and Homogenization Pressure.

SUMMARYResearch backgroundEmulsion technology is a suitable way of encapsulating, protecting and releasing hydrophobic bioactive compounds for application in food industries, but they are thermodynamically unstable systems. Good results have been achieved for emulsions stabilized by protein-polysaccharide complexes subjected to high-pressure homogenization. Improved stabilization of oil-in-water emulsions results from electrostatic complexes formed between proteins and polysaccharides at pH lower than the protein isoelectric point, which adsorb at the oil-water interface. In addition, polysaccharides contribute to emulsion stability by increasing viscosity of the continuous phase. The aim of this work is to investigate the production of carotenoid-rich buriti oil emulsions using soy protein isolate and high-methoxyl pectin as stabilizers.Experimental approachUsing a rotatable central composite experimental design, we assessed the effects of oil content, soy protein isolate/high-methoxyl pectin ratio and homogenization pressure on the stability, droplet size, electrical conductivity, electrical charge, microstructure and rheological behaviour of the emulsions.Results and conclusionsAn optimized emulsion was produced with 28% buriti oil, 55% soy protein isolate, and homogenization pressure of 380·105 Pa. This emulsion was stable for at least seven days, presenting reduced average droplet size, low electrical conductivity and high modulus of negative charges. The mechanical spectra showed that the emulsion behaved as a viscoelastic gel under oscillatory, non-destructive shearing, whereas shear-thinning behaviour took place under steady shear conditions.Novelty and scientific contributionThe optimized buriti oil emulsions stabilized by soy protein isolate and high-methoxyl pectin could be suitable for fat substitution, energy reduction and carotenoid enrichment in food products, such as dairy and bakery products, ice cream, salad sauces and vegetable-based cream.

Design and development of an active indirect solar dryer for cooking banana

Active indirect mode solar dryers were designed and constructed for drying of cooking banana in Umudike, Nigeria. The dryers were constructed with special focus on the air inlet, to examine if the air inlet area had effect on the performance of the dryers. The air inlet areas were considered in five levels and four shapes namely: square, rectangular, circular and triangular. A total of 52 dryers were required for the experiment, based on the combination of factors and levels of experiment using the Central Composite Rotatable Experimental Design adopted for the study. Fresh samples of cooking banana were obtained from a local market, peeled, cleaned and sliced to the desired thickness for the drying experiment. Open sun drying was used a control. Data was collected on a two hourly interval on each drying day between the month of January and March. The dryers were observed to reduce the moisture content of the products from 4.53 to 1.57 kg within 9 to 16 h of drying, while moisture was reduced from 68.97 to 12.00% (wet basis). The dryers were able to conserve almost 40% of the total drying time for the products when compared to open sun drying. The efficiency of the driers ranged from 13.85 to 31.84%. It was observed that the air inlet area of the dryer had significant effect on the efficiency of drying of the product.

Studies on the tribological behaviour of exsitu-synthesized AlMg1SiCu/titanium carbide/molybdenum disulfide hybrid composites

AlMg1SiCu alloy based metallic composites are nowadays extensively employed in automobiles and machinery components. In this study, an attempt has been made to investigate the influence of adding hard and soft micro particulate reinforcements, on the microstructure and the tribological behaviour of AlMg1SiCu hybrid composites. The exsitu synthesized hybrid composites were processed using the conventional melt-stir casting route, by introducing titanium carbide (TiC) micro particles in different levels ranging between 4–12 wt% and molybdenum disulfide (MoS2) micro particles, at varying levels between 1–5 wt% respectively. In the present study, the macro hardness profile was recorded using the Rockwell hardness B-scale. The fabricated composites were subjected to the pin-on-disc wear analysis. Five-level rotatable central composite experimental design was adopted for planning the wear analysis, and the second order mathematical model was developed with an adequacy of above 95%. The microstructure and elemental mapping of the hybrid composites were recorded using SEM, which revealed the uniform dispersion of the reinforcement particulates. The x-ray Diffraction (XRD) results also confirmed the presence of the reinforcement phases. It was observed that, the macro hardness and wear resistance of the hybrid composites, improved significantly with increase in weight fraction of both TiC and MoS2 micro particulate reinforcements.

Selection and incorporation of hydrocolloid for gluten-free leavened millet breads and optimization of the baking process thereof

Suitability amongst the hydrocolloids, - tragacanth gum, gum arabic, guar gum and xanthan gum to be used as an ingredient for mimicking the action of gluten was carried out based on gluten-free millet (pearl, little and kodo) bread quality in terms of expansion (cm), specific volume (mL/g) and textural characteristics. Xanthan gum was found to be the most suitable hydrocolloid for rendering an acceptable structure to the bread. Gluten-free leavened breads were made using central composite rotatable experimental design of response surface methodology with proofing time (Pt, 1.3–4.7 h), baking time (Bt, 32–48 min) and baking temperature (BT, 158–192 °C) as input variables. Statistically significant (p < 0.01) second order models were used to understand effect of variables upon the responses. Textural property of little millet flour bread was observed to be better amongst all the millet breads. Optimum conditions for little millet bread in terms of Pt, Bt and BT was 3.5 h, 48 min and 190 °C, respectively; under these conditions this bread exhibited best expansion, springiness and hardness. 2-tailed paired t-test revealed that quality characteristics of bread prepared at model predicted values did not significantly (p < 0.01) differ from that actually prepared under optimum condition.

Photo-Fenton process at natural conditions of pH, iron, ions, and humic acids for degradation of diuron and amoxicillin.

Effect of ferric ions at concentrations typically found in natural waters (0.05 to 1.06mgL-1) and low H2O2 concentrations (between 0.5 and 17.9mgL-1) on simulated sunlight-induced (300Wm-2) photo-Fenton degradation at initial neutral pH (7.0) of amoxicillin and diuron in Milli-Q water was studied using an rotatable central composite experimental design 22 with a central and two axial points. H2O2 concentration was the parameter playing the key role on the degradation of both pollutants. Despite that initial pH was 7.0 in Milli-Q water, this latter decreased rapidly in the first minutes, reaching values of 3.5 and 5.0 for diuron and amoxicillin respectively after 15min of simulated sunlight irradiation. In contrast, in presence of bicarbonate/carbonate (HCO3-/CO3=), fluoride (F-), and humic acids (HAs) at concentrations found often in surface and well waters with ferric ion and H2O2 concentrations of 0.3 and 9.7 and 15.2mgL-1 respectively, both pollutants exhibited a strong degradation keeping the circumneutral pH. Amoxicillin and diuron degradation byproducts found by HPLC/MS were compatible with HO• and/or CO3-• radical attack. Several photo-induced processes such as photo-Fenton (by dissolved ferric-HA complexes), heterogeneous photocatalysis (by colloidal iron), UV-B H2O2 photolysis, irradiated-dissolved organic matter, and their reactions with pollutants would be the main oxidative route responsible of degradations. These findings demonstrated that it could be possible using iron concentrations often found in natural waters to oxidize via photo-Fenton processes among other events, organic pollutants at natural pH conditions.

Microwave assisted extraction and characterization of polysaccharide from waste jamun fruit seeds

The intention of current work is to recover/extract polysaccharide from jamun fruit seeds (waste) by microwave assisted solid-liquid extraction (MAE) technique using four-factor (microwave power (MWP), pH, time (MWT) and solid to liquid (SL) ratio) five-level central composite rotatable experimental design (CCRED). The observed data was evaluated by statistically and a mathematical model (polynomial) was developed to predict the polysaccharide yield. Numerical optimization technique is used to attain the ideal optimal condition (microwave power of 515 w, pH of 3.2, MWT of 3.1 min and SL ratio of 1:15 g/ml) to retrieve maximal yield of polysaccharide and attained optimal condition was experimentally validated. The experimental yield of polysaccharide (4.71 ± 0.02%) was matched with predicted value (4.72%). Physico-chemical properties of the polysaccharide extracted at optimal condition was investigated. Fourier Transform Infrared Spectroscopy (FTIR) evaluation were carried out in this study to characterize the polysaccharide. Scanning Electron Microscopy (SEM) was also utilized to reveal the morphology of raw and extracted plant sample.

Physical Properties of Bread from Wheat– Cassava Flour Composite Using Response Surface Methodology (RSM)

Physical properties of bread prepared from 90% wheat and 10% cassava composite flour were investigated using response surface methodology. A central composite rotatable experimental design with two factors and five levels was used. The independent variables were baking temperature and time. Thirteen baking trials were performed with five central points and eight non central points. The results showed that the crumb moisture, specific loaf volume, crumb hardness and overall acceptability values ranged from 33 - 39.6%, 3.80 - 4.8cm3/g, 63.00 - 70.25N and 6.2 - 8.1 respectively. There were significant differences (p< 0.05) in the physical properties of the bread samples and the physical properties were affected by the baking temperature and time. The bread samples baked at temperature of 195°C for 16.89 minutes were highly preferred by the panelists and the best processing conditions were baking temperature of 181.20°C at 24.18 minutes with desirability of 0.85. This research suggested that 10% inclusion of cassava in the production of bread would further increase the utilization of cassava flour, thereby promoting the economic value of the indigenous crop.

Effects of extrusion on the properties of shrimp and cassava-based snacks

PurposeThe purpose of this paper is to use Amazon River shrimp meal and cassava flour as the raw materials for the production of an extruded product. Both these raw materials are highly consumed foods in the northern region of Brazil, but are not processed industrially, only being used for local consumption and there is little in the literature concerning their use.Design/methodology/approachThe study was carried out using a full 23 factorial central composite rotational experimental design with three independent variables, which were shrimp meal; feed moisture content and temperature, with four replicates at the central point and six axial points. The dependent variables were: expansion index (EI), bulk density (BD) and specific length (SL). The principal component analysis (PCA) was applied for the sensory analysis.FindingsAlmost all the parameters studied had a significant influence (p<0.10) on the responses analysed. The product was well accepted by 78.11 per cent of the volunteers. Increases in the shrimp meal and feed moisture contents strongly influenced the physical analyses (EI, BD and SL) of the extruded product. In the application of the PCA for the sensory analysis, the influence of the variables aroma, appearance and purchase intention corresponded to PC1, and that of the variables flavour, texture, global acceptance and colour to PC2.Social implicationsThe development of a product based on animal protein which is more available than common snacks, as a way of reducing the negative environmental impact caused by the disposal of Macrobrachium amazonicum, which is considered as accompanying fauna to artisan fishery.Originality/valueThe originality of this paper lies in the quest for the development and/or application of technologies that allow for the use of raw materials from the Amazon as a way of aggregating value to the existing wealth of this region.

Co-pyrolysis of seaweeds with waste plastics: modeling and simulation of effects of co-pyrolysis parameters on yields, and optimization studies for maximum yield of enhanced biofuels

ABSTRACTCo-pyrolysis of Enteromorpha prolifera (EP) (seaweeds) with waste plastics (high density polyethylene (HDPE)) for maximum yield of enhanced biofuels has been investigated. Main and interaction effects of three effective co-pyrolysis parameters (pyrolysis temperature, feedstock blending ratio and heating rate) on bio-oil, char and gas yields were also modeled and simulated, respectively. Optimization studies using central composite rotatable experimental design were performed in Design Expert® Version 8.0.6 software to predict the optimal conditions of co-pyrolysis parameters for maximum yield of enhanced biofuels. Analysis of variance was carried out to determine whether the fit of multiple regressions was significant for second order models. Compositions of bio-oils and chars from the pyrolysis of EP, HDPE and their mixtures at different blending ratios were determined using gas chromatography-mass spectrometry analysis technique. Other important properties of oils and chars such as heating values, water contents, and specific gravity were also determined. Results of products’ analysis revealed that synergistic effect exists between EP and HDPE during co-pyrolysis which led to enhanced seaweed biofuels. Statistical analysis’ results unveiled that feedstock blending ratio, pyrolysis temperature and heating rate significantly influenced bio-oil and char yield rates.

Germination in Optimal Conditions as Effective Strategy to Improve Nutritional and Nutraceutical Value of Underutilized Mexican Blue Maize Seeds.

Germination of grains is a bioprocess of emerging interest to improve nutritional and nutraceutical profile of cereals in a natural way. The aim of this work was to identify optimal germination conditions (temperature/duration) for producing a functional blue maize flour with maximum values of protein content (PC), antioxidant activity (AoxA), and total phenolic and anthocyanin contents (TPC, TAC). A central composite rotatable experimental design (response surface methodology) with two factors [Germination temperature (Gtemp, 20-40°C) / Germination duration (Gdur, 12-220h)] in five levels was used (13 treatments). Blue maize seeds were soaked in distilled water (25°C / 12h) before germination. The sprouts were dried, tempered (25°C), and ground to obtain germinated blue maize flours (GBMF). The prediction models developed for each response variable showed high coefficients of determination, demonstrating their adequacy to explain the variations in experimental data. Maximum values of PC, AoxA, TPC, and TAC were attained at Gtemp= 26.9°C / Gdur =207.7h. Optimized germinated blue maize flour (OGBMF) presented higher PC (+38.48%), AoxA (ABTS: +192%, ORAC: +160%, DPPH: +148%), TPC (+79%), and TAC (+9.9%) than unprocessed blue maize flour (UBMF). Germination at optimal conditions is an effective strategy to increase the nutritional/nutraceutical quality of blue maize seeds, thus the flour of these germinated seeds could be used for the development of functional foods.

Optimization of Processing Conditions on Some Selected Mechanical Properties of Cookies from Wheat-Cocoyam Flour Using Response Surface Methodology (RSM)

This study investigated the optimization of processing conditions on some selected mechanical properties of cookies from wheat-cocoyam flour using response surface methodology. The purpose of this research is the utilization of cocoyam crops in the production of cookies. A central composite rotatable experimental design with two factors and five levels was used. The independent variables were baking temperature and time. The responses are moisture (Y1), energy to break (Y2), break strength (Y3), force at break (Y4) and overall acceptability (Y5). Thirteen baking trials were performed with five central points and eight non central points. The results shows that moisture, energy to break, break strength, force at break and overall acceptability ranged from 4.43-8.94%, 0.0027-0.422N/m, 0-0.90.83N/mm2, -6-90.83N, 3.50-8.80 respectively. The results indicated that there were significant difference (P<0.05) in the moisture content and mechanical properties of the cookies and were all affected by baking temperature and time. The cookies produced at 210°C for 30 minutes were most preferred by the panelists. The best processing conditions were samples baked at 190.15°C at 27 minutes with desirability of 0.700. In conclusion, the production of cookies using 10% inclusion increases the usage of underutilized cocoyam crops and also leads to the development of more cookies to meet people’s demand.