Alumnae Research Articles

Study on the opportunity to improve the quality of the flour for pastry by adding chemical leavening agents

Food products that do not require practices for processing, and are easy to prepare have attracted the attention of consumers. An example of this type of product is the premixes formulations for cake mix which allows the cake to be made easily and quickly. The consumer of this type of product has the expectation, when following the instructions, to obtain a uniform and quality product. There are many different chemical leavening agents available to the baker. These include baking soda (sodium bicarbonate), ammonium bicarbonate, potassium bicarbonate, baking powder (baking soda, calcium phosphate and sodium aluminum sulfate) and leavening acids. Generating CO2 and neutralizing sodium bicarbonate is the primary role of leavening acids, but, it is important not to forget their secondary role and their effects. Taking into consideration these facts, the objective of experiments was to establish the connection between quantity and quality of leavening agents and the quality of bakery products. As the chemical leavening agents get into flour, it is also important to comprehend how they influence the rheological parameters of flour with direct implication in the quality of the products made. For experiments, baking powder was used, which was added in specific quantities to wheat flour. The flour samples were made, and the samples obtained were sensory evaluated in the panel. Correlating Mixolab Profiler indices with the baking samples, and also with the legislation regarding, the best results were obtained for flour with 2% baking powder.

Performance and Nanostructure Simulation of Phosphogypsum Modified by Sodium Carbonate and Alum.

This paper presents a new modification of the nanostructure of CaSO4·2H2O crystals containing nanopores. This nanoporous structure was achieved in phosphogypsum samples that were modified by sodium carbonate and alum. The effects of sodium carbonate and alum on the properties of phosphogypsum were studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods were used to explore the micro-mechanism of the composite system. Subsequently, molecular dynamics simulations were used to study the nanopore structures of the modified CaSO4·2H2O. The results show that the addition of sodium carbonate and alum reduced the absolute dry density by 23.1% compared with the original phosphogypsum sample, with a bending strength of 2.1 MPa and compressive strength of 7.5 MPa. In addition, new hydration products, sodium sulfate and sodium aluminum sulfate, were formed in the sample doped with sodium carbonate and alum. A new nanostructure of CaSO4·2H2O crystal containing nanopores was formed. Molecular simulations show that the hydration products were responsible for the surface nanopore formation, which was the main factor leading to an increase in mechanical strength. The presented nanopore structure yields lightweight and high strength properties in the modified phosphogypsum.

Research on Obtaining Silica Xerogels from Nepheline and Study of some of their Physical and Chemical Properties

The article presents a method to obtain silica xerogels with developed specific surface based on nepheline concentrate acid decomposition in C2H5OH-H2SO4 system. It was found that the use of ethanol instead of water produces stable and steady silica gels. It is proved that the use of ethanol results in almost complete deposition of soda alum and aluminum potassium sulphate out of nepheline decomposition solution without its additional cooling, due to their extremely low solubility in alcohol solution. The morphology, structural and surface properties of synthesized xerogel sample with ~600 m2/g specific surface area (based on the analysis) were investigated; its mixed micro-and mesoporous structure was established. Electron probe microanalysis showed chemical purity of the resulting SiO2.

Spotlights: Faculty, Alumna, and Courses

Spotlights: Faculty, Alumna, and Courses

Using Alumnae as Standardized Patients: Interviewing Using Videoconferencing.

Using Alumnae as Standardized Patients: Interviewing Using Videoconferencing.

Using Alumnae as Standardized Patients

Using Alumnae as Standardized Patients

Effects of chemical leavening system and processing conditions on the opacity and other quality characteristics of whole-wheat flour tortillas

Chemical leavening is a neutralization reaction that can affect not only the opacity but also other physical and chemical properties of tortillas. Whole-wheat flour (WWF) tortillas is often associated with lack of sufficient opacity, generally considered as quality defect in tortillas. The objectives of this research were to evaluate the effects of types and amounts of leavenings (acids and base), hot press and dough temperature on the quality attributes of WWF tortillas. Three leavening acids, three levels of sodium bicarbonate (SBC) (1%, 1.5%, and 2%), hot-press temperatures of 160 °C, 177 °C, and 193 °C, and two dough temperatures (25 °C and 35 °C) were used. Sodium aluminum phosphate (SALP) produced more opaque tortillas than sodium acid pyrophosphate-28 (SAPP-28), followed by sodium aluminum sulfate (SAS). Increased amount of SBC and lower dough temperature improved opacity. Higher hot-press temperature produced lighter weight, thinner, and bigger diameter tortillas. Higher amount of SBC produced smaller, thicker, and brighter color tortillas. WWF tortillas made with SAS had the largest breaking force, while tortillas with SALP had the smallest breaking force as determined by TA-XTPlus Texture Analyzer. After 45 days of storage at room temperature, all tortillas showed decreased breaking force and extensibility.

INTEGRATED DISEASE CONTROL STRATEGIES FOR LENGTHENING THE STORAGE LIFE OF PAPAYA CULTIVARS 'RED LADY' AND 'RATHNA'

Anthracnose (Colletotrichum gloeosporioides), stem-end rot (Phomopsis caricae-papayae and Lasiodiplodia theobromae), and Phomopsis rot of papaya are major diseases resulting in relatively high post-harvest losses (up to 45%) in Sri Lanka. Current consumer preference is for tropical fruits free of agrochemicals. The objectives of the present investigation were to identify the in vitro efficacy of basil oil (Ocimum basillicum) and alum (sodium aluminium sulphate) on fungal pathogens of papaya fruit and to develop a relatively safe, in vivo integrated disease control strategy. Alum (1% (w/v)) and basil oil (0.12-0.16% (v/v)) in a liquid bioassay, indicated fungistatic and fungicidal efficacy on Colletotrichum gloeosporioides, Lasiodiplodia theobromae and Phomopsis caricae-papayae isolated from 'Red Lady' and 'Rathna' cultivars of papaya. In vivo investigation of fruits of both cultivars harvested from orchards in Sri Lanka at 25% maturity level indicated that papaya washed in 1% (w/v) alum and subsequently sprayed with an emulsion solution of 0.16% (v/v) basil oil and enclosed in styrofoam sleeves could be stored for a period of 14 days at 12-14°C. The visual quality rating (VQR) was high (11-13), and shriveling and “green islands” were low on fruits with zero disease severity where results were statistically similar to a Bavistin 500 mg/L (systemic fungicide) treatment. Physico¬chemical properties assessed were unaffected by the treatments and were comparable to the control (washed only in water). The organoleptic properties were slightly low in fruits subjected to cold temperature compared to fruits subjected to ambient temperature. No residues of basil oil could be detected on fruits by gas chromatography at the end of the experimental period. This integrated treatment strategy of papaya could be adopted for sea shipment and temperature-regulated supermarket storage of papaya fruits where storage life could be lengthened by up to 14 days.

Disease control strategies for extending storage life of papaya (Carica papaya), cultivars 'Red Lady' and 'Rathna'

Anthracnose (Colletotrichum gloeosporioides), stem-end rot (Lasiodiplodia theobromae) and Phomopsis rot (Phomopsis caricae-papayae) are major post-harvest diseases in papaya resulting in relatively high postharvest losses, up to 45%, in Sri Lanka. The current consumer preference is for tropical fruits free of synthetic pesticides. The objectives of the present investigation were to identify major post-harvest pathogens in papaya fruits, test in vitro fungitoxic effect of basil oil (Ocimum basillicum) and alum (sodium aluminium sulphate) on major fungal pathogens of papaya fruit and develop a relatively safe, disease control strategy. Alum (1% w/v) and basil oil (0.12– 0.16% v/v) in a liquid bioassay, indicated fungistatic and fungicidal efficacy on C. gloeosporioides, L. theobromae and P. caricae-papayae isolated from ‘Red Lady’ and ‘Rathna’ cultivars of papaya. In vivo investigation of fruits of both papaya cultivars harvested from fruit plantations in Sri Lanka (‘Red Lady’–Yatawarawatta plantation, Kurunegala, ‘Rathna’ – CIC plantation, Kekirawa and the Agricultural farm, Polonnaruwa) at 25% maturity level indicated that papaya washed in 1% (w/v) alum and subsequently sprayed with an emulsion solution of 0.16% (v/v) basil oil and enclosed in styrofoam sleeves could be stored for 14 days at 12–14 °C. The visual quality rating (VQR) was high (11–13), shriveling and ‘green islands’ were low on fruits with zero disease severity where results were statistically similar to 500 mg/L Bavistin treatment. Physicochemical properties assessed were unaffected by the treatments and were comparable to the controls washed only in water. The organoleptic properties were slightly low in fruits subjected to cold temperature compared to fruits subjected to ambient temperature. No residues of basil oil could be detected on fruit peel by gas chromatography at the end of the experimental period of 14 days. The treatment strategy developed could be adopted for sea shipment or temperature-regulated supermarket storage of papaya fruits where storage life could be lengthened up to 14 days. DOI: http://dx.doi.org/10.4038/cjsbs.v41i1.4535 Ceylon Journal of Science (Bio. Sci.) 41 (1): 27-34, 2012

Purification and Characterization of a Hexanol-Degrading Enzyme Extracted from Apple

An enzyme having activity toward n-hexanol was purified from apple, and its biochemical characteristics were analyzed. The purification steps consisted of sedimentation with ammonium sulfate, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephadex G-100 column. The obtained enzyme had a yield of 16.00% with a specific activity of 18879.20 U/mg protein and overall purification of 142.77-fold. The enzyme showed activity to isoamylol, 1-propanol, n-hexanol, and isobutanol but not toward methanol and ethanol. With n-hexanol as a substrate, the optimum conditions were pH 4.0 and 30 °C for enzyme activity and pH 3.0-4.0 and temperatures below 40 °C for enzyme stability. The enzyme activity was increased significantly by adding l-cysteine and Fe(2+) at all tested concentrations and slightly by Zn(2+) at a high concentration but decreased by additions of EDTA, Ga(2+), K(+), Mg(2+), sodium dodecyl sulfate (SDS), sodium aluminum sulfate (SAS), dithiothreitol (DTT), and glutathione (GSH). The enzyme activities toward n-hexanol and n-hexanal were increased by NADH but decreased by NAD(+), in contrast to a decrease toward n-hexane by addition of both NAD(+) and NADH.

An Integrated Treatment of Basil Oil (<i>Ocimum basilicum</i>) and Alum with Modified Atmosphere to Control Crown Rot Disease in Embul Banana

A study was undertaken with the objective of developing environmental friendly integrated treatment strategies for controlling crown rot disease in Embul banana. The fungicidal potential of 1% alum (sodium aluminium sulphate) was observed in vitro . Findings indicate that alum+basil oil (0.16% or 0.20% v/v) treated 80, 85, 90 day mature Embul banana fruits were relatively free from crown rot disease after subjecting to modified atmosphere packaging (MAP) and storage at optimum temperature. Crown rot disease severity of 85-day mature and vacuum packed 1% alum (w/v) washed banana was lower and comparable to carbendazim (bavistin) treatment. After ripening, there was no significant difference in physico-chemical properties (titratable acidity, total soluble solids, pH, fruit firmness) of all treated fruits compared to the control. Sensory properties were slightly affected as compared to untreated fruits. MAP and vaccum packaging in combination with alum and/ or basil oil spray treatments at 12-14°C could extend the storage life of Embul banana upto 32 days which could be recommended for sea shipment. Key words : Crown rot; Embul banana; Essential oils; Post harvest disease control DOI: 10.4038/tare.v12i1.1980 Tropical Agricultural Research & Extension 12(1):2009 23-30

Effects of Leavening Acids and Dough Temperature in Wheat Flour Tortillas

ABSTRACTFunctionality of four leavening acids (sodium aluminum phosphate [SALP], sodium aluminum sulfate [SAS], monocalcium phosphate [MCP] and sodium acid pyrophosphate [SAPP‐28]) was evaluated during processing of wheat flour tortillas. Formulas were optimized to yield opaque, large‐diameter tortillas with pH 5.9–6.1. Each leavening acid and sodium bicarbonate was first evaluated at 38°C and then evaluated in combination with fumaric acid at 34 and 38°C. Ionic and pH interactions of leavening salts adversely affected dough properties and resting time. Opacity and pH of tortillas prepared with MCP was lower than for other treatments. Higher dough temperature required more leavening acid and base to compensate for some of the loss of CO2 incurred during dough mixing and resting at 38°C. The addition of fumaric acid decreased the amount of leavening acid, the dough‐resting time and tortilla pH, and improved storage stability. Combinations of MCP, SALP (or SAS), and fumaric acid produced dough and tortillas with good qualities. Tortillas prepared using SALP (or SAS) and fumaric acid tended to be of better quality.

凝灰岩表面での塩類集積現象に見られるアルノーゲンの産状および生成過程 埼玉県吉見丘陵を例として

On the wall of a tunnel dug in sandy tuff of Fukuda formation of Neogene system southwest of Yoshimi hill in Yoshimi Town, Hiki County of Saitama Prefecture, sulfate minerals have crystallied on the surface due to weathering of rocks. Amount of crystallization changes considerably between dry and wet periods, and distribution and mineral species also vary. Minerals confirmed with results of XRD as surface crystals are mostly alunogen, jarosite and gypsum, accompanied with halotrichite, epsomite, thenardite, tamarugite, and sodium alum as well. Crystallization of these minerals, particularly of alunogen, on the weathering process of rocks indicates that this weathering is advancing in strongly acidic environment compared with that of ordinary weathering. Alunogen is a mineral that is originally formed in concern with water vaporization in a strongly acidic environment as a secondary mineral mainly of volcanic sublimate, sinter and sulfide deposit. At this site of study, alunogen crystallizes at ordinary temperature by covering rack surface in skinny shell, and in paragenesis with jarosite. It is regarded by observing formation process of the crystallization and its distribution that alunogen crystallized with action of water strongly acidified by the formation of jarosite and oxidation of pyrite and H2S.

Mount St. Augustine volcano fumarole wall rock alteration: mineralogy, zoning, composition and numerical models of its formation process

Intensely altered wall rock was collected from high-temperature (640 °C) and low-temperature (375 °C) vents at Augustine volcano in July 1989. The high-temperature altered rock exhibits distinct mineral zoning differentiated by color bands. In order of decreasing temperature, the color bands and their mineral assemblages are: (a) white to grey (tridymite-anhydrite); (b) pink to red (tridymite-hematite-Fe hydroxide-molysite (FeCl 3) with minor amounts of anhydrite and halite); and (c) dark green to green (anhydrite-halite-sylvite-tridymite with minor amounts of molysite, soda and potash alum, and other sodium and potassium sulfates). The alteration products around the low-temperature vents are dominantly cristobalite and amorphous silica with minor potash and soda alum, aphthitalite, alunogen and anhydrite. Compared to fresh 1986 Augustine lava, the altered rocks exhibit enrichments in silica, base metals, halogens and sulfur and show very strong depletions in Al in all alteration zones and in iron, alkali and alkaline earth elements in some of the alteration zones. To help understand the origins of the mineral assemblages in altered Augustine rocks, we applied the thermochemical modeling program, GASWORKS, in calculations of: (a) reaction of the 1987 and 1989 gases with wall rock at 640 and 375 °C; (b) cooling of the 1987 gas from 870 to 100 °C with and without mineral fractionation; (c) cooling of the 1989 gas from 757 to 100 °C with and without mineral fractionation; and (d) mixing of the 1987 and 1989 gases with air. The 640 °C gas-rock reaction produces an assemblage consisting of silicates (tridymite, albite, diopside, sanidine and andalusite), oxides (magnetite and hercynite) and sulfides (bornite, chalcocite, molybdenite and sphalerite). The 375 °C gas-rock reaction produces dominantly silicates (quartz, albite, andalusite, microcline, cordierite, anorthite and tremolite) and subordinate amounts of sulfides (pyrite, chalcocite and wurtzite), oxides (magnetite), sulfates (anhydrite) and halides (halite). The cooling calculations produce: (a) anhydrite, halite, sylvite; (b) Cu, Mo, Fe and Zn sulfides; (c) Mg fluoride at high temperature (> 370 °C); (d) chlorides, fluorides and sulfates of Mn, Fe, Zn, Cu and Al at intermediate temperature (170–370 °C); and (e) hydrated sulfates, liquid sulfur, crystalline sulfur, hydrated sulfuric acid and water at low temperature

Fumarole distribution, morphology, and encrustation mineralogy associated with the 1986 eruptive deposits of mount St. Augustine, Alaska

Numerous rootless fumaroles were developed on pyroclastic flows and a lava flow generated during the March 1986 eruptive cycle of Mount St. Augustine. Gases issued from fumarole vents with four different shapes: fissure, phreatic explosion crater, single/multiple ovoid opening, and diffuse, multiple opening. Fumarole distribution and morphology were controlled by preeruption drainage and topography, as well as by the thickness, compaction, and settling of the flow deposits. Fumarole temperatures measured in June and July 1986 ranged from 75°–394°C. Varying amounts of colorful and often roughly zoned encrustations are associated with all fumarole vent shapes. Only six types of crystalline phases were detected by X-ray diffraction, with gypsum the most abundant mineral, followed by anhydrite, sulfur, tridymite, halite, and soda alum. Scanning electron microscopy and energy dispersive X-ray analysis revealed a number of amorphous phases, mainly halogen-rich, as well as other minor crystalline phases. The mineral assemblages in the encrustations suggest formation conditions for these deposits within a general range of 25°–250°C in an oxidizing environment. Many of the amorphous phases are metastable and upon cooling of the fumarole lose nonstructural water and crystallize to more stable forms. The high halogen contents of the fumarole condensates and the mineralogy, chemistry, and morphology of the encrustations support leaching of the andesitic ash and lava flow by condensed acid vapors as the primary source for the chemical components contained in the encrustations. Comparison of traceelement (Sr, Ba, V, Co, Ni, and Cr) contents in unaltered and altered ash suggests that trace-element distribution follows a pattern of isomorphic substitution in the encrustation phases.

Effect of Na + on sulphation and related reactions over a commercial claus alumina catalyst

The influence of Na + on the nature of sulphate species, alumina sulphation and the regeneration of spent Claus alumina catalyst either by hydrogen sulphide reduction or water leaching has been studied by Fourier transform-IR spectroscopy and microgravimetry. Na + strongly modifies the nature of sulphate species on alumina, leading to mixed sodium aluminium sulphate and sodium sulphate species. Na + appears to promote sulphur dioxide adsorption and catalyst sulphation, the latter occurring at a lower temperature. It does not affect the reducibility of sulphate by hydrogen sulphide, which is found to be a slow process, but Na + facilitates the removal of sulphate species by water leaching and this appears to be an efficient process for elimination of sulphate.

Peisleyite, a new sodium aluminium sulphate phosphate

AbstractA new sodium aluminium sulphate phosphate has been named peisleyite. It has the ideal formula Na3Al16(SO4)2(PO4)10(OH)17 · 20H2O. It occurs as fine-grained, compact, brittle, white material on dumps at Tom's Phosphate Quarry, near Kapunda, South Australia. Strongest X-ray diffraction lines are 12.63 Å (100) 010, 7.82(35) 11, 5.41(35) 004, 7.59(30) 111. Unit cell parameters are a 13.31 ± 0.006, b 12.62 ± 0.006, c 23.15 ± 0.01 Å, β 110.0°±0.03°, Z = 2.

Kinetics of sulfation of alkalized alumina (Na2O·Al2O3)

A thermogravimetric analysis was made of the sulfation of alkalized alumina between 300 and 600°C, using sulfur dioxide concentrations typical of stack gases, 0.001–0.025 atm. Both dry gases and gas mixtures containing up to 0.024 atm water vapor were used. The primary reaction product is sodium sulfate (I), but at 500°C and above, sodium aluminum sulfate forms at the later stages of the sulfation. The rate of formation of sodium sulfate is proportional to the sulfur dioxide concentration, independent of oxygen partial pressure and proportional to the unreacted Na2O in alkalized alumina. The rate of sulfation appears to be controlled by formation of sodium sulfite which is subsequently oxidized to the sulfate. The experimental activation energy for the formation of sodium sulfate is low. In the absence of small amounts of water vapor a marked decrease in the rate occurs.

Electron spin resonance studies of Cr3+ impurities in soda alum

The electron spin resonance of Cr3+ impurities was studied in two types of crystals which grew out of a saturated solution containing a mixture of sodium sulfate, aluminum sulfate, and chromium sulfate dopant. One of the crystals was identified as soda alum, NaAl(SO4)2∙12H2O, which has cubic symmetry, while the other was a monoclinic crystal of undetermined structure. In soda alum, four differently oriented, but otherwise equivalent, magnetic complexes of chromium were found. Each complex exhibited an axial distortion along one of the crystal body diagonals. In the monoclinic crystal, two differently oriented, but otherwise equivalent, magnetic complexes of chromium were found. Each of the complexes exhibited a strong rhombic distortion but none of the magnetic axes coincided with the crystallographic axes. However, the complexes were related by twofold symmetry to the monoclinic b axis. The ESR results of the two crystals were fitted to suitable spin Hamiltonians and the pertinent parameters were determined. The crystallographic parameters (a, b, c) of the monoclinic crystal were determined by X-ray analysis.

Extracting alumina from silicates by melting, quenching, and sulfuric acid leaching

More than 95% of the alumina was extracted from various silicates, such as anorthosite, clay, and kyanite, containing 30 to 45% alumina, in the melting-quenching-sulfuric acid leaching experiments conducted by the U. S. Bureau of Mines. Requirements for optimum extraction consisted of quenching the melted materials to a completely amorphous state and adjusting the weight ratio of SiO2 to CaO + Na2O in the quenched product within the range of about 3.0 to 3.7. At higher ratios, recovery of alumina decreased, and at lower ratios gelation of the leach-slurry ensued. The pregnant solution was readily separable from the leached residues, a basic sodium aluminum sulfate was precipitated from the solution at 200° C, by hydrolysis, and alumina was produced from the precipitate.