Rubalya Valantina | SASTRA University (original) (raw)

Papers by Rubalya Valantina

Nanoparticle TiO2 was synthesized by the co-precipitate method and was dispersed in palm oil blen... more Nanoparticle TiO2 was synthesized by the co-precipitate method and was dispersed in palm oil blended with Moringa oleifera seed oil (Enriched palm oil-EPO). Structural and compositional analysis of TiO2 nanoparticles was carried out using SEM (Scanning Electron Microscope), XRD (X-Ray Diffraction) and FTIR analysis (Fourier Transform Infrared Spectroscopy). Using the analytical method, particle dimension, crystallite size by Debye Scherrer’s equation and vibrational energy of the molecule was investigated. Palm oil was blended with synthesised Moring oil to enhance its oxidative stability. TiO2 nanoparticles were dispersed at different volume fraction in EPO to analyse the temperature dependent physical properties. Bio-degradable lubricant nature of TiO2 based nanofluid was investigated by the variation of viscosity and density with temperature (30 to 60˚C). The amphiphilic properties of fatty acids in blended oils can contribute better lubrication compared to mineral oils. Experime...

Asian Journal of Chemistry, 2012

Asian Journal of Chemistry, 2009

This paper presents the microcontroller based measurement and analysis of kinematic viscosity of ... more This paper presents the microcontroller based measurement and analysis of kinematic viscosity of vegetable oils that reduces human effort and increases the accuracy of measurement. The developed system consists of AT mega 328 microcontroller, ultrasonic range detecting sensor, temperature sensor, heater, solid heater controller, keyboard and LCD to display the results. The instrument will keep the oil at any desired temperature and measure the time of 50cc of the sample collection so as to compute viscosity of the sample. Viscosities of rice bran oil and corn oil at temperatures ranging from 303-363K are calculated from the measurement of time taken to collect 50cc. Observations reveal that there is a decrease in viscosity with increase in temperature due to decrease in intermolecular forces. The experimental results obtained are compared with a standard instrument and the correlation coefficient is found to be accurate (R 2 = 0.998). The

international food research journal, 2015

Vegetable oils contain natural antioxidants like sterols, phosphatides, tocopherols, tocotrienols... more Vegetable oils contain natural antioxidants like sterols, phosphatides, tocopherols, tocotrienols etc. In the present study, the efficiency and stability of natural antioxidant in unrefined mustard oil, groundnut oil and sesame oil on heating is studied. The oils undergo five cycles of heating to a frying temperature (210°C) and their antioxidant activity is premeditated using radical scavenging assay. The inhibition concentration of unheated and heated mustard oil, groundnut oil and sesame oil (with solvent benzene) and the stability of natural antioxidant at different concentrations are evaluated using 2, 2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method. The result showed that the antioxidant activity in unheated oils are more compared to heated oils using ABTS radical scavenging activity (IC50 24.31, 25.26 and 24.42 for unheated and IC50 49.7, 54.55 and 46.39 for heated). The scavenging activity is also studied usin...

international food research journal, 2013

Commercially available extra virgin oil is added with coconut oil and sunflower oil at different ... more Commercially available extra virgin oil is added with coconut oil and sunflower oil at different proportion. The variation of rheological and ultrasonic parameters in the binary mixtures of the oils are studied and reported. The oil is subjected to frying temperature 210°C repeatedly so that compositional changes take place in the fatty acids. A general decrease in the viscosity of oils is observed with increase in temperature and the difference in the variation in terms of percentage of adulteration is also studied. An empirical correlation between viscosity and temperature is also determined so as to predict viscosity and adulteration in oil at intermediate temperatures. The changes in the quality of olive oil is premeditated from the changes in the parameters such as viscosity, density, ultrasonic velocity, acoustic impedance, adiabatic compressibility and intermolecular free length, from which the adulteration in the oil can be easily perceived compared to analytical techniques.

Atmospheric oxygen can react spontaneously with lipids and other organic compounds causing struct... more Atmospheric oxygen can react spontaneously with lipids and other organic compounds causing structural degradation, which is ultimately responsible for the loss of quality in food. When oil is exposed to frying, the triglycerides are converted into myriad. However, this oxidation process can be prevented or retarded by the addition of synthetic or natural antioxidants. Recent developments in Fourier transforminfrared (FT-IR) spectroscopy instrumentation extend its application to the field of food research, facilitating particularly the studies on edible oils and fats. Commercial sunflower oil is exposed to repetitive and simulated deep-frying at 2500C for five times. In this work, FT-IR spectroscopy is used as an effective analytical tool to study the saturation and unsaturation composition of heated and unheated oils. In addition, an analytical technique for the measurement of carbonyl compounds in oils, produced after heating, has been employed. A novel methodology in gas chromatog...

Materials Science, 2015

The realistic structures of CuO, CuO 2 and Cu 2 O were completely optimized using density functio... more The realistic structures of CuO, CuO 2 and Cu 2 O were completely optimized using density functional theory approach. The different structures were optimized to study the structural stability, dipole moment, point symmetry, HOMO-LUMO gap, ionization potential, electron affinity and binding energy of CuO, CuO 2 and Cu 2 O. The electronic properties of clusters were discussed in terms of HOMO-LUMO gap, density of states, ionization potential and electron affinity. This information will provide an insight for the synthesis of nanomaterials with proper geometry which finds its potential importance in engineering applications.

Superlattices and Microstructures, 2014

ABSTRACT The band structure and transport properties of pristine, boron, gallium and arsenic subs... more ABSTRACT The band structure and transport properties of pristine, boron, gallium and arsenic substituted AlP nanoribbon are studied using density functional theory. The band structure of pristine, boron, gallium and arsenic substituted AlP nanoribbon exhibits semiconducting behavior. The substitution of boron decreases the band gap of AlP nanoribbon. The substitution of group-III semiconductor has much influence in density of states. The major contribution is observed in p and d orbitals. The electron density increases with boron substitution and there is a slight decrease in electron density for gallium substitution. The transmission of AlP nanoribbon molecular device is analyzed with two probe method. The substitution impurity and bias voltage influence the transmission across AlP nanoribbon. From the results, it is inferred that the band structure and electronic transport properties can be fine-tuned with substitution impurity along AlP nanoribbon.

ACS Food Science & Technology

Iranian Journal of Science and Technology, Transactions A: Science

Soft chemical method was used to prepare ZnO nanoparticle at different mole concentrations, and t... more Soft chemical method was used to prepare ZnO nanoparticle at different mole concentrations, and the particles was dispersed in oil (groundnut oil and mustard oil). Dielectric behavior of the nanofluid was premeditated at different temperatures. The composition of ZnO was studied using energy-dispersive X-ray spectroscopy, and structural analysis of ZnO ceramic was studied with X-ray diffractograms technique that investigates the prepared powders are crystalline in nature with an average grain size of 29 nm. Surface morphological analysis was investigated using scanning electron microscope. To investigate the dielectric constants (DC) of ZnO nanofluid, a capacitive method using impedance LCR (inductance capacitance and resistance) meter was experiential between the temperatures 45–85 °C. It was observed that DC of nanofluid decreases with rise in temperature and attain saturation at high temperature due to the stability of ZnO. The experiential data and its deviation of linearity were studied using Arrhenius and Andrade’s equation taking ln (ε′) with temperature (R2 > 0.915). tert-butylhydroquinone (TBHQ-antioxidant) was added with the base fluid and nanofluid to compare the increasing stability of ZnO nanofluid. The perpetual dielectric nature of ZnO nanofluid at high temperature can be used in industries as a coolant and lubricant.

Grasas y Aceites

Oils are commonly used in cooking as a frying medium which has been constantly subjected to diffe... more Oils are commonly used in cooking as a frying medium which has been constantly subjected to different levels of heating. In this work, we have considered the most commonly used oils namely peanut oil and corn oil. Quality analyses of corn and peanut oils were made by relating macroscopic properties (ultrasonic velocity, viscosity, and density) to microscopic parameters (intermolecular free length, adiabatic compressibility etc.,) by subjecting them to six cycles of heating (190 ˚C). Variation in the mentioned property indexes, the degree of degradation and reusability for the next heating cycle that could be used in the food industry and processing were monitored. Using Newton-Laplace and Wood’s equation, the adiabatic compressibility, acoustic impedance, and intermolecular free length of the oil were estimated from the experimental data. Ultrasonic velocity was observed linearly as related to viscosity with the dependency factor (R2 = 0.932). With the aid of experiential data, the ...

In the food industry, rheological behavior and thermal degradation is the important parameters re... more In the food industry, rheological behavior and thermal degradation is the important parameters required to determine the quality and stability of food system. In this paper, the rheological behavior and thermal degradation of rice bran and corn oil, is investigated. Redwood viscometer is used to measure viscosity at various temperatures. A 16F88 microcontroller based temperature controller is designed to measure and to keep the temperature of the oil at the desired temperature. The rice bran and corn oil exhibit Newtonian behavior during heating and cooling in the temperature range 30o to 90°C.. The oils also exhibit Newtonian behavior even after heating to the frying temperature. A non-Newtonian characteristic is observed in sunflower oil due to rancidity that changes the complex chemical composition of oil. To characterize the cooking oils the structural study is carried out using FTIR spectra analysis and it is observed that the antioxidant activity is stronger in rice bran oil. ...

Fried food products have unique organoleptic and sensorial properties, including flavor, texture ... more Fried food products have unique organoleptic and sensorial properties, including flavor, texture and appearance largely enjoyed by the customer. The high temperatures used during frying, in the presence of oxygen, induce chemical changes of the oils inevitably reducing their shelf life and affecting the quality of the fried food. Thermal degradation of edible oils occurs in three stages, related to the decomposition of polyunsaturated, monounsaturated and saturated fatty acids. In this work kinematic viscosity is measured for heated and unheated palm oil using Redwood viscometer. The oil is studied by heating it four cycles to frying condition and the variation of viscosity is measured from 30°C to 90 °C and it is noted that r square value ranges from 0.986 to 0.995 for the dependable parameter viscosity. The oxidative deterioration of the oils heated to 210°C for 0.5, 1, 1.5 and 2 hours is also studied. FTIR spectroscopy is used to non-invasively measure the degradation of frying o...

Iranian Journal of Science and Technology Transactions A Science, Aug 29, 2018

Fats and oils are recognized as essential nutrients in human diets. Nutritionally, they are conce... more Fats and oils are recognized as essential nutrients in human diets. Nutritionally, they are concentrated source of energy (9 cal/ gram); provide essential fatty acids which are the building blocks for the hormones needed to regulate bodily systems; and are a carrier for the oil soluble vitamins A, D, E and K. Kinematic Viscosity of unheated and heated (270°C) rice bran oil is measured 30o to 90°C. In this paper, the antioxidant stability in palm oil and rice bran oil at different times of heating is investigated using the parameters like density, viscosity, adiabatic compressibility and acoustic impedance of the oils at different times of heating. The antioxidant stability is resolute at every time of heating. Hence, it can be recommended that rice bran oil can be used for frying without adverse effect preventing the incidence of malignancy and coronary heart diseases.

Journal of Food Science and Technology, Oct 31, 2015

Journal of Molecular Liquids