Development of bakery products for greater adult consumption based on wheat and rice flour

The present investigation was developed as a contribution to Guatemalan's elderly food and nutrition. Its main objective was to evaluate the chemical, nutritional and sensory quality of bread prepared from the partial substitution of wheat flour with rice flour. Wheat flour substitutions with rice flour in the order of 15, 20, 30, 40, 50 and 60% were evaluated. Differences with the control (100% wheat bread) were found during the process of preparation, as well as texture, volume, height, weight and specific volume. Important effects in dough handling were noted specifically in the 40, 50 and 60% rice bread. Thus, a sandy texture was found in breads of higher rice levels. The bread protein quality increased with the level of substitution; however the protein quality difference between the wheat bread and the bread with 60% rice flour did not achieve statistical significance. Based on a statistical analysis of the physical properties the bread with 30 and 40% rice flour was selected, and through a preference test between these last two, the 30% rice flour bread was selected as the sample best suited to the present study's purposes. This bread was not different to wheat bread in many nutritional parameters, although in others it showed to be superior. Each serving size of bread has a weight of 80 grams (2 slices) that contributes adequate quantity of calories, protein and sodium, although a little less dietary fiber than 100% wheat bread.     

Preparation of cookies with a flour mixture of wheat and green plantain

With the purpose of diversifying the use of green plantain flour, a functional evaluation was performed by substituting 7% of chocolate cookie wheat flour by dehydrated green plantain flour; thus allowing to obtain a product with good physical and organoleptic qualities, as well as a better nutritional quality, as for dietary fibre and resistant starch. As a result of the use of this dehydrated green plantain flour (G-HT/HPV), the values of some chemical components increased significantly (P 0.05 Pound) in comparison to the standard cookies (GP): ash (2.46 to 2.69%), proteins (8.93 to 9.69%), dietary fiber (4.97 to 5.40%), resistant starch (0.19 to 0.23%) and total sugar (25.26 to 30.55). The G-HT/HPV complies with the industrial requirements as for moisture (2.7300%), ph (8.43), aw (0.205) and color (L = 31.78; a = 7.95 and b = 10.51). Besides, thanks to the use of G-HT/HPV the flours scattering during the kneaded process was diminished, thus reducing the cookie diameter and increasing the resistance to breaking (1.48 to 2.06 Kgf), in comparison to the GP. While evaluating the shelf life for G-HT/HPV, it was demonstrated that was affected by moisture, pH, aw and acidity after the first month of storage. In the preference comparison test between the G-HT/HPV and a trademark cookie (GC), no significant differences were founded. Both were accepted and qualified between good and very good, as for sensorial features like colour, fragrance and taste. However, significant differences were detected in relation to texture, and they were corroborated in the texture profile analysis. In this test the panel staff, while evaluating both types of cookies demonstrated that there are 8 features that can be used to describe them: firm, crumble, crisp, mealy, soft, lumpy, particle size and chewy.     

Evaluation of Isolated Impact of Trans Fatty Acids on Short Dough Product

In this study, the effects of trans fatty acids (TFAs) on rheological properties of dough (elastic moduli (G’), loss moduli (G”), complex modulus (G*)) and textural properties of dough and cookie (hardness) were studied. Two different groups of fat samples having different TFA composition but similar solid fat content (SFC) were prepared. Samples of the first group (group 1) had TFA between 0.0 and 56.23 %, while the samples of the second group (group 2) contained trans isomers ranging from 0.0 to 44.40 %. Texture measurements of different doughs and cookies prepared with different fat samples were performed. Texture measurements indicated that hardness values of doughs increased from 3950 ± 420 to 5498 ± 506 g in group 1 and 4700 ± 501 to 6787 ± 369 g in group 2 with increased amounts of TFAs. A particularly high, almost three‐fold increase in complex modulus values was observed in the dough samples containing the highest TFA levels compared with samples containing 0.0 % TFA. Although not significantly different, mean hardness and relative sound intensity values of cookies displayed an initial decreasing trend and then both parameters had maximum values when the TFA content was at maximum in both groups.     

Evaluation of cookies enriched with corn germ and soy fiber

The objective of this study was to evaluate four cookie formulations which wheat flour was partially substituted by free-fat corn germ flour and/or soy fiber. Baking quality, protein, fat, ash, dietary fiber, hardness, color, Protein Efficiency Ratio PER and Apparent Digestibility in vivo were determined. A trained panel evaluated color, hardness and fracturability of cookies. Dietary fiber of cookies varied from 8.2 to 24.9% and protein from 11.3 to 12.7%. The source and amount of dietary fiber modified physical, sensory, and nutritional properties of cookies. Cookies formulated with 20% corn germ flour gave the highest PER, Digestibility Aparente in vivo, and acceptance by consumers. This study demonstrated the potential use of free-fat corn germ and soy fiber as functional ingredients.     

Supplementation of bakery items with high protein peanut flour

White skin peanuts were defatted with hexane to produce flours with 55–60% protein. The peanut flour was used to replace 12.5% of the wheat flour in bread, 100% of wheat flour in muffins, and 10, 15 or 50% of the wheat flour in cookies. At 12.5% levels of peanut flour, total solids, protein, moisture retention of bread after baking, and dietary fiber contents are increased without affecting loaf vol-ume. Crust color of supplemented bakery items is darker brown, texture is coarse for bread and harder in cookies, but not enough to make them unacceptable. Peanut flour muffins with a net protein content of 33–40% can serve as a high protein snack food or bakery item, possibly for patients with celiac disease who cannot tolerate wheat flour. Moisture retention in supplemented products was greater than in nonsupplemented controls. Net increase of protein in baked items varied from 4% increase for 12.5% peanut flour bread to 30% for the all-peanut flour muffins. Other physical and chemical prop-erties of these products are presented to support potential applica-tions of peanut flour as a supplement for selected food products.     

Baked product development based fermented legumes and cereals for schoolchildren snack

The objective of this work was to develop three foodstuffs based on mixes of wheat and fermented and non-fermented legumes, for the purpose of contributing with a healthy alternative for school snacks. To this aim, refined wheat flour was partially substituted with whole legume flours for the preparation of cakes, brownies and cookies, foodstuffs traditionally consumed by school age children. Cakes were formulated substituting 20% of wheat flour with Phaseolus vulgaris flour, brownies with 30% of Cajanus cajan flour and cookies with 30% of Vigna sinensis flour, using fermented and non-fermented legumes in the three products. When these products were subjected to sensorial evaluation through a test of degree of acceptability and using a hedonic scale of 7 points, values higher than 5 in the attributes taste, color and overall appraisal were found for all the products. In addition, the preference was measured with a group of 90 school children, corroborating the results obtained at laboratory level. Chemical characterization showed protein contents between 12 and 13% for the cake, 10 and 11% for the brownies and 10% for the cookies and protein digestibilities in vitro of 91%, 87% and 93%, respectively. The calorie supply, calculated per portion was of 199 kcal, 246 kcal and 237 kcal, for cakes, brownies and cookies, respectively. It was concluded that it is technically possible to incorporate fermented and non-fermented Phaseolus vulgaris, Vigna sinensis and Cajanus cajan, to highly consumed products such as cakes, brownies and cookies with a higher nutritional content and well-accepted by school-age children.     

Multicomponent isotherms for biosorption of Ni and Zn

The capability of wheat straw to adsorb Ni²⁺ and Zn²⁺ was investigated using a batch system. The equilibrium removal of metal ions was obtained between 2.5 and 5 h for Ni²⁺ and about 3 h for Zn²⁺ over the initial concentration range from 5 to 150 ppm. Of the total amount of metal uptake by wheat straw, about 50% was adsorbed in the first 30 min. At a low initial concentration of 5 ppm, wheat straw was capable to reduce the metal concentration down to less than 1 ppm. For single-metal solutions, among the three models tested, namely the Langmuir, the Freundlich and the Temkin isotherms, the Freundlich model was suitable to describe the adsorption equilibrium for Ni²⁺ and Zn²⁺. For bimetal solutions, the IAST-Freundlich multicomponent isotherm best fitted the experimental data, among the four isotherm models investigated, the modified Langmuir multicomponent model, the Langmuir partially competitive model, the Freundlich multicomponent model and the IAST-Freundlich multicomponent model. The negative Gibbs free energy changes obtained at lower concentrations indicates that the adsorption was spontaneous. However, the spontaneity of the biosorption decreased with increases in the metal concentration from 5 to 50 ppm. For metal concentrations higher than 50 ppm, the adsorption became non-spontaneous. Scanning electron microscopic (SEM) images of wheat straw were also taken to exam the surface structure of the wheat straw along with the energy dispersive spectrum (EDS) analysis. The results obtained confirmed the adsorption of Ni²⁺ and Zn²⁺ on wheat straw, and showed that the inner surface of the wheat straw appeared to provide more adsorption sites for metal binding.     

Handling properties of cereal materials in the presence of moisture and oil

A powder flow analyzer attached to a Texture Analyser (Stable Micro Systems, UK) was used to compare the flow behaviour of four cereals systems: maize and wheat (in both starch and flour forms), as functions of particle size and distribution, water content and the addition of different types of oil. It was expected that the smaller the particle size the higher the tendency to stick (because of less free volume between the particles), but that was not the case. The results showed that wheat starch used, with bigger particle size than maize starch, had higher cohesion properties and as water content increases the cohesion increases by the same magnitude. This was attributed to the differences in granular shape as well as protein quantity and quality. Caking strength for both starches was influenced by the water content; in particular at 30% water content (w/w), neither cohesion nor caking indices could be measured for wheat starch because of the high stickiness of the particles.Although the two flours had particles of very similar sizes, with differences in the distributions only, maize showed higher cohesion indices compared to wheat flour. These values decreased with increasing water content. The caking property for maize was not significantly affected by water content with values of approximately 100 ± 5. The caking strength increased for wheat flour from 8 to 500 as moisture increased from 12.5 to 30%. This was ascribed to the differences in hydration properties of the two flours. For wheat flour and as the water content increased, gluten started to form and would require more than 30% to form a homogenous, visco-elastic mass.Generally, cohesivity and cake forming ability were affected by water content as well as the physical state of the oil i.e. by the solid/liquid ratios. As water content increases, wheat starch showed the greatest packing and cohesive behaviour, with and without the oil, while maize flour exhibited the weakest packing and cohesive properties.     

Morphological and mechanical properties of dried skimmed milk and wheat flour mixtures during storage

Five mixtures of dried skimmed milk (DSM) and wheat flour (WF) were prepared and stored for 45 days at 20 °C and various relative humidities (RH) from 0% to 85%. Morphological properties, particle size distributions and mechanical properties were studied before and during storage. Scanning electronic microscopy (SEM) showed that samples stored at high RH (59-85%) agglomerated and formed a compact mass of powder due to caking phenomenon. The caking intensity increased with storage relative humidity and was expressed as the maximum force (F_max.) calculated from force/compression curves. DSM powders showed stick-slip behaviour during deformation and, moreover, this phenomenon increased with the DSM ratio in the mixture (up to 20 ± 1 N for 100% DSM) and disappeared with storage relative humidity.     

Sesame seed (Sesamum indicum, L.). II. Use of sesame flour in protein mixtures

The results obtained in the first part of this study demonstrated that the sesame flour protein is of reasonable quality and can be utilized, although it has a low lysine content and is rich in sulfur amino acids. Based on the initial data, the sesame flour was supplemented with other meals: "carioca" beans, pigeon pea, and soybean. Nine diets were prepared and the best combination was that of 50% sesame flour protein and 50% pigeon pea, the PER of which was 2.28. Breads were made with these systems, as follows: 100% sesame flour, 100% wheat flour, 50% sesame flour + 50% wheat flour; 30% sesame flour + 70% wheat flour; 30% sesame flour + 30% soybean flour + 40% wheat flour. These were evaluated through sensory analysis by a grading system. Good acceptance was obtained with the bread prepared with 30% sesame flour + 70% wheat flour. Its external and internal appearance, as well as its organoleptic characteristics were close to the bread, with 100% wheat flour. Sesame flour at the 50% proportion gave a bread of medium quality. The protein mixtures of sesame flour and soybean flour were well accepted. Some of the panel members reported that it had a taste somewhat like integral bread.     

Electrophoretic deposition of ethanol steam-reforming catalysts on metal plates for the development of catalytic-wall reactors

A procedure based on electrophoretic deposition (EPD) was developed to coat metal plates with powder catalysts. The method was tested on stainless-steel plates with three Ni-based catalysts for the steam reforming of ethanol. The catalysts (Ni/La₂O₃/γ-Al₂O₃) contained 15% Ni and 8% La, and were prepared using three types of γ-alumina with different textural properties. The powder catalysts were suspended in isopropanol, and EPD deposition was performed with a voltage of 100 V and a distance between electrodes of 2 cm. Deposition time was varied between 3 and 7 min, which gave a thickness of the catalyst layer from around 30 to 100 μm. The morphology of the catalyst layer was dependent on the textural characteristics of the γ-Al₂O₃ used to prepare the catalyst. The activity of the catalyst plates was tested at 773 K using a steam to carbon molar ratio of 4. Significant differences in the selectivity towards ethanol dehydrogenation, reforming, and dehydration to ethylene could be observed between the three catalysts. Carbon deposition on the surface of the plates could be easily determined by SEM/ESEM.     

Tailoring the properties of yttria-stabilized zirconia powders prepared by the sol-gel method for potential use in solid oxide fuel cells

Yttria-stabilized zirconia (YSZ) powders have been prepared by the sol-gel method, following two alternative procedures: a series of powders was obtained by drying the sol-gel solutions in air at 100 °C until dry residue, and another series of powders was obtained by scratching the thin films deposited on cylindrical wide flat glassy surfaces after evaporating to dryness in air at 100 °C for 2 h. Samples were characterized by Scanning Electron Microscopy (SEM), nitrogen adsorption at −196 °C and Fourier Transform Infrared (FT-IR) spectroscopy. In general, a noticeable contraction of the pores is observed as the molecular size of the alcohols used grows. Powders prepared by conventional drying of sol-gel solutions at 100 °C exhibit remarkably high values of specific surface area (up to 148 m² g^− 1). On the contrary, samples prepared by scratching of the deposited thin films show a noticeable decrease in their specific surface area. Values of fractal dimension follow the same trend and indicate that, in general, the texture of the samples is mainly microporous for the first series of samples and more ordered for the second one. Finally, in order to investigate the effect of the calcination temperature on the morphological and textural properties of 3 mol% yttria-stabilized zirconia powders, once the 3YSZ powders were dried at 100 °C they were subjected to calcination at different temperatures. The experimental results suggest that the removal of residual water and alcohol occluded within the powder particles as well as the elimination of gases produced during the calcination stage play a very important role in the development of the porosity and surface area of the samples.     

Enhancement of thermal conductivity of ethylene glycol based silver nanofluids

Nanofluid is a kind of new engineering material consisting of solid particles with size typically of 1-100 nm suspended in base fluids. Nanofluids offer excellent scope of enhancing thermal conductivity of common heat transfer fluids. In the present study, nanofluids are synthesized using silver nitrate (precursor), ethylene glycol (reducing agent), and poly(acrylamide-co-acrylicacid) (dispersion stabilizer). The different concentrations of silver nanofluid (1000-10,000 ppm) were synthesized. The silver particles present in colloidal phase have been characterized by EDX, XRD, UV-visible spectroscopy, Zeta potential and transmission electron microscopy (TEM). The stability as well as thermal conductivity of these nanofluids was determined with a transient hot-wire apparatus, as a lapse of time after preparation. Typically, 10,000 ppm silver nanofluid exhibited rapid increase in the particle size with the passage of time. Thermal conductivity of silver nanofluids increased to 10, 16, and 18% as the amount of silver particles in nanofluid were 1000, 5000, and 10,000 ppm, respectively. After 30 days of preparation, the thermal conductivity of 1000 and 5000 ppm silver nanofluids decreased slightly from 10% and 15% to 9% and 14%, respectively. In addition, the thermal conductivity of 10,000 ppm nanofluid was decreased from 18% to 14% after 30 days. It is very interesting to report that the silver particles were aggregated in early stage of preparation (up to 15 days), which leads to the increase in the size of silver particles. However, no significant change was observed after 15 days which indicates the stability of silver nanofluids.     

The effect of rapeseed oil added to control grain dust on the quality of wheat

The effect of spraying edible rapeseed oil on controlling dust in barley, oat, rye and wheat has been investigated. Both the amount of rapeseed oil deposited and initial dust level govern the dust reduction level whereas the type of grain is immaterial. Regarless of the initial dust concentration, about 80% dust could be reduced with only 0.05% rapeseed oil addition. When the initial dust level exceeded 750 mg/m³, dust reduction could reach 90%. Although some dust adhered to the wheat kernels after rapeseed oil application, except for slight deteriorations in flour ash and color, other flour analytical properties, physical dough properties, and milling and baking qualities were unaffected. Paper no. 477 of the Canadian Grain Commission, Grain Research Laboratory, Winnipeg, Manitoba, Canada, R3C 3G9.     

Novel polymer fibers prepared by electrospinning for use as the pore-former for the anode of solid oxide fuel cell

One-dimensional polyvinyl alcohol (PVA) fibers prepared by electrospinning technique are used as a novel pore-former for the conventional NiO/yttria-stabilized zirconia (YSZ) anodes of solid oxide fuel cell (SOFC). This pore-former forms wire-like pores in the anode substrates, which are beneficial for rapid transport of the fuel and byproduct. The advantage of using this pore-former over the conventional ones (e.g. wheat flour and carbon) is that only a small amount of fibers could generate large amount of continuous pores within the anode for gas transport. In addition the cell with PVA fibers as pore-former for anode exhibits enhanced anode electrocatalytic activity and the cell performance significantly, compared to the cells without pore-former and with wheat flour as pore-former. In this research, an anode-supported SOFC with PVA fibers as pore-former for anode exhibits an open-circuit voltage (OCV) of 1.08 V and maximum power density of 751 mW cm⁻² at 800 °C.     

Hydrogen production by aqueous-phase reforming of glycerol over nickel catalysts supported on CeO2

Nickel catalysts supported on CeO₂ were prepared and evaluated in aqueous-phase reforming of glycerol. Three different methodologies of synthesis were used: wet impregnation, co-precipitation and combustion, and the catalysts were characterized by chemical composition, textural analysis, crystalline structure and reducibility. The reaction was carried out in a batch reactor with solution of 1 and 10 wt.% glycerol, at 523 and 543 K. A maximum glycerol conversion of 30% was achieved by the catalyst prepared by combustion at 543 K using solution 1% glycerol. In the gas phase, the molar fraction of H₂ was always higher than 70% and formation of CH₄ was very low (< 1%). The increase in glycerol concentration decreases the conversion and H₂ formation.     

Baking performance of palm diacylglycerol bakery fats and sensory evaluation of baked products

Baking performance of palm diacylglycerol (PDG)‐enriched fats was evaluated and compared with that of commercial bakery fats. PDG‐enriched shortenings were found to produce cakes with significantly (p<0.05) higher mean values for specific volume than that produced from commercial shortening. As for PDG‐enriched margarines, cookies prepared from PDG‐enriched margarines were found to have reduction in cookies spread as compared to that of commercial shortening. Nevertheless, this reduction was not statistically significant. Sensory evaluation of the baked products was also conducted. Both trained and untrained panelists rated cakes prepared from PDG‐enriched shortenings as having higher moistness, softer, and airier texture than that of commercial shortening. This is in agreement with findings from principal component analysis (PCA). As for cookies, both trained and untrained panelists rated cookies prepared from PDG‐enriched margarines as having softer texture and compactness compared to that prepared from commercial margarine.     

Preparation of cellular SiBOC foams by thermo-foaming of polymethylvinylborosiloxane–wheat flour dough

A novel method for the preparation of SiBOC foams from a polymethylvinylborosiloxane (MVBS) solution in ethanol using wheat flour as a foam stabilizer and pore template has been reported. A dough prepared by mixing the MVBS solution and wheat flour undergoes foaming at 180°C due to the stabilization of bubbles created by ethanol vapor by the adsorption of wheat flour particles on their surface. The ceramization of the foamed body at 1500°C followed by burnout of carbon produced from the wheat flour results in SiBOC foams of hierarchical pore structure. The foam density (.68–.44 g cm⁻³), average cell size (1.81–.58 mm), compressive strength (3.9–1.7 MPa), and thermal conductivity (.33–.21 W m⁻¹ K⁻¹) decrease with an increase in wheat flour to MVBS weight ratio from .25 to 1. The population of smaller pores (∼5–50 μm) created by wheat flour particles on cell walls and struts increases with an increase in wheat flour to MVBS weight ratio. The presence of β-SiC and turbostratic graphite nanodomains in amorphous SiBOC is evidenced by X-ray diffraction and transmission electron microscopy analysis.     

Effects of compression on porous texture of clay powder: Application to uranium diffusion

This paper presents the results of tests conducted on the compaction properties of clay. Swelling clays of Algeria are being examined as components of the buffer material. Knowledge of the porous texture in clay samples is a useful element in the microstructural characterization of such materials. The prepared materials were characterized by X-ray diffraction, Differential Thermal and Thermo Gravimetric Analysis, Laser Granulometry, Scanning Electron Microscopy, mercury porosimetry and nitrogen adsorption/desorption to obtain information about their structure and surface texture. The cationic exchange of clay minerals, in particular smectites, influences the cation retention and diffusion processes. These processes influence the migration of contaminants from waste disposal sites through clay barrier. In the present work we studied the effect of cation exchange and compaction on the textural properties of clay. Pellets of the Na-saturated and bulk clay samples were prepared by compression of the powder samples using uniaxial stress at different pressures in order to obtain different densities. The pressures of 31–127 MPa are applied for the production of cylindrical samples with diameter of 20 mm and heights of 15–30 mm. The effect of compaction of clay on the diffusion behavior of uranium was studied for the safety assessment of the radioactive waste. The diffusion process of uranium in compacted clay has been modeled by second Fick's law taking into account the effect of sorption and considering the non-steady state. The diffusion coefficients and profiles concentration values of uranium were calculated by computational method using numerical program based on Newton–Raphson algorithm.     

Effect of fermentation conditions on yeast growth and volatile composition of wine produced from mango (Mangifera indica L.) fruit juice

In this study mango juice fermentation at laboratory scale with controlled inoculation using selected yeast strain was performed (Saccharomyces cerevisiae 101). Effect of fermentation conditions (temperature, pH, SO₂ and aeration) on wine fermentation was evaluated based on yeast growth, duration, fermentation rate and volatile composition. The composition of the major volatile compounds with low boiling points was determined by gas chromatography under the different operating conditions of fermentation temperature (15-35 °C), pH (3.5-6.0), SO₂ (100-300 ppm) and aeration (initial dissolved O₂ and shaking at 30 rpm). Temperature had important effect on yeast growth and on the levels of volatile compounds. It was observed that the final concentrations of ethyl acetate and some of the higher alcohols decreased when fermentation temperature increased to 25 °C (35 mg/l at 15 °C and 27 mg/l at 25 °C). SO₂ stimulated the yeast growth up to certain level and in excess it inhibited the yeast metabolism. Ethanol concentration slightly increased with the addition of 100 ppm SO₂ (8.2 g/l) and decreased with increase in concentration of SO₂ (6.2 g/l in 300 ppm SO₂). Aeration by shaking increased the viable cell count (from 52 × 10⁶ in the absence of oxygen to 98 × 10⁶ in shaking at 30 rpm) but decreased the ethanol productivity (from 7.2 in initial dissolved O₂ to 6.5 g/l shaking at 30 rpm). With the results obtained it was concluded that the temperature (25 °C), pH (5), SO₂ (100 ppm) and must with initial oxygen were optimum for better quality of wine from mango fruits. The results of the present study considering the traditionally recognized preference for low alcoholic fermentation temperatures in wine making.