Comparative TG/DTG/DTA+FTIR Studies Concerning the Stability of Some Mineral and Vegetable Electro-Insulating Fluids

Thermal TG/DTG/DTA analysis coupled with FTIR spectroscopy was applied to some sorts of mineral and vegetable oils used in electrical equipment. On heating in inert atmosphere, it was observed that the mineral oils vaporize, while the vegetable oils undergo hydrolysis, yielding fatty acids as main volatiles, as indicated by FTIR. In synthetic air, the FTIR spectra of gaseous products confirm the presence of similar oxidation products, both for mineral and vegetable oils. The TG results indicated that the vegetable-based oils exhibit a substantially higher thermal stability than the mineral oils. The presence or absence of anti-oxidant inhibitors in these oils greatly influences the onset of the oxidation process in air environment factor, as results from the DTA results.

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Mixing Oil-Based Microencapsulation of Garlic Essential Oil: Impact of Incorporating Three Commercial Vegetable Oils on the Stability of Emulsions

Foods ◽

10.3390/foods10071637 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1637

Author(s):

Yunjiao Zhao ◽

Rui Liu ◽

Cuiping Qi ◽

Wen Li ◽

Mohamed Rifky ◽

...

Keyword(s):

Essential Oil ◽

Vegetable Oils ◽

Encapsulation Efficiency ◽

Ostwald Ripening ◽

Corn Oil ◽

Whey Protein Concentrate ◽

Diallyl Disulfide ◽

Active Components ◽

The Stability ◽

Garlic Essential Oil

The active components in garlic essential oil are easily degradable, which limits its application in the food industry. Vegetable oils (VOs) were used to improve the stability of garlic essential oil (GEO) emulsion. The volatile compounds of GEO and its mixtures with vegetable oils (VOs), including corn oil (CO), soybean oil (SO), and olive oil (OO) indicated that GEO-VO mixtures had a higher percentage of Diallyl disulfide and Diallyl trisulfide than pure GEO. Adding an appropriate amount of VOs promoted the GEO emulsion (whey protein concentrate and inulin as the wall materials) stability in order of CO > SO > OO. Evaluation of the encapsulation efficiency, controlled release, and antimicrobial activity of GEO-VO microcapsules showed that the GEO was successfully entrapped and slowly released with active antibacterial activities on both E. coli and S. aureus. Collectively, these results implied that VOs, especially for 20% CO, improved the stability of GEO emulsions and the encapsulation efficiency of GEO microcapsules. The mechanism might be related to (1) the regulating effect of density difference between oil and water phases on prevention to gravitational separation, (2) the promotion to the compatibility of GEO and VOs to inhibit the phase separation caused by Ostwald ripening.

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Carrier-microencapsulation using Al-catecholate complex to suppress arsenopyrite oxidation: Evaluation of the coating stability under simulated weathering conditions

MATEC Web of Conferences ◽

10.1051/matecconf/201926806002 ◽

2019 ◽

Vol 268 ◽

pp. 06002 ◽

Cited By ~ 1

Author(s):

Kensuke Seno ◽

Ilhwan Park ◽

Carlito Tabelin ◽

Kagehiro Magaribuchi ◽

Mayumi Ito ◽

...

Keyword(s):

Protective Coating ◽

Sulfide Mineral ◽

Sulfide Minerals ◽

Low Ph ◽

Oxidation Products ◽

Arsenic Sulfide ◽

Catecholate Complex ◽

Coating Stability ◽

The Stability

Arsenopyrite (FeAsS) is the most common primary arsenic-sulfide mineral in nature, and its oxidation causes the release of toxic arsenic (As). To mitigate these problems, carrier-microencapsulation (CME), a technique that passivates sulfide minerals by covering their surfaces with a protective coating, has been developed. In the previous study of authors on CME, Al-catecholate complex significantly suppressed arsenopyrite oxidation via electron donating effects of the complex and the formation of an Al-oxyhydroxide coating. For the application of this technique to real tailings, however, further study should be carried out to elucidate long-term effectiveness of the coating to suppress arsenopyrite oxidation. This study investigates the stability of the coating formed on arsenopyrite by Al-based CME using weathering tests. The Al-oxyhydroxide coating suppressed arsenopyrite oxidation until about 50 days of the experiment, but after this, the amounts of oxidation products like dissolved S and As increased due to the gradual dissolution of the coating with time as a result of the low pH of leachate. This suggests that co-disposal of Al-based CME-treated arsenopyrite with minerals that have appropriate neutralization potentials, so that the pH is maintained at around 5 to 8 where Al-oxyhydroxide is stable.

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MECHANOCHEMICAL ACTIVATION METHOD TECHNOLOGICAL PROCESS REFINING OF VEGETABLE OILS

Известия вузов. Пищевая технология ◽

10.26297/0579-3009.2020.2-3.6 ◽

2020 ◽

Author(s):

В.И. МАРТОВЩУК ◽

С.А. КАЛМАНОВИЧ ◽

А.А. ЛОБАНОВ ◽

Е.В. МАРТОВЩУК

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Acid Composition ◽

Vegetable Oils ◽

Structural Changes ◽

Mechanochemical Activation ◽

Cavitation Effect ◽

Temperature Mode ◽

The Stability ◽

Local Pressures

Исследовано влияние механохимической активации на гидратируемость фосфолипидов растительных масел. Для эксперимента использовали механохимический активатор, обеспечивающий высокие локальные давления, сдвиговые деформации и кавитационный эффект, при следующих параметрах работы: давление на контактирующих поверхностях 70 МПа, частота 180 Гц, скорость сдвига 10200 с–1, размер капли эмульсии 1–2 мкм. Обработку образцов подсолнечного масла осуществляли в течение от 0 до 80 с при температурах 50, 60 и 70°С. Активность фосфолипидов оценивали по величине их адсорбции на границе с полярной поверхностью (водой) в оптимальном температурном режиме при обработке в механохимическом активаторе и без нее. Установлено, что механохимическая активация способствует снижению энергии активации с 6,4 до 4,7 кДж/моль за счет химических и структурных изменений фосфолипидов. В жирнокислотном составе фосфолипидов на 10–12% увеличилось содержание олеиновой кислоты при соответствующем уменьшении линолевой; в фосфатидилэтаноламинах и фосфатидилсеринах отмечено увеличение до 3% содержания пальмитиновой кислоты и незначительно – стеариновой кислоты. Эти изменения жирнокислотного состава и физических свойств фосфолипидов способствуют повышению их гидратируемости и уменьшению доли полиненасыщенных жирных кислот, что должно обеспечить стабильность обработанных в механохимическом активаторе масел к окислению при хранении. The effect of mechanochemical activation on the hydration of phospholipids of vegetable oils has been studied. A mechanochemical activator providing high local pressures, shear deformations and cavitation effect was used for the experiment with the following operating parameters: pressure on the contact surfaces of 70 MPa, frequency of 180 Hz, shear rate of 10200 s–1, the size of the emulsion drop of 1–2 microns. Processing of sunflower oil samples was carried out during 0 to 80 s at temperatures of 50, 60 and 70°C. The activity of phospholipids was estimated by the amount of their adsorption at the border with the polar surface (water) in the optimal temperature mode when processed in a mechanochemical activator and without it. It was found that mechanochemical activation contributes to a decrease in the activation energy from 6,4 to 4,7 kJ/mol due to chemical and structural changes in phospholipids. In the fatty acid composition of phospholipids, the content of oleic acid increased by 10–12% with a corresponding decrease in linoleic acid; in phosphatidylethanolamines and phosphatidylserines, the increase in the content of palmitic acid was noted to 3%, and stearic acid – slightly. These changes in the fatty acid composition and physical properties of phospholipids contribute to increasing their hydration and reducing the proportion of polyunsaturated fatty acids, which should ensure the stability of the oils processed in the mechanochemical activator to oxidation during storage.

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Degradability of chlorine-free bleachery effluent lignins by two fungi: effects on lignin subunit type and on polymer molecular weight

Canadian Journal of Microbiology ◽

10.1139/m94-032 ◽

1994 ◽

Vol 40 (3) ◽

pp. 192-197 ◽

Cited By ~ 7

Author(s):

Matthias Bergbauer ◽

Claudia Eggert

Keyword(s):

Manganese Peroxidase ◽

Trametes Versicolor ◽

Substantial Reduction ◽

Pulp Mill ◽

Oxidation Products ◽

Free Medium ◽

Polymer Molecular Weight ◽

Lignin Phenols ◽

The Stability ◽

Cuo Oxidation

A bleachery effluent from a sulfite process pulp mill, which was extracted with alkali and treated with oxygen and hydrogen peroxide (EOP), was treated with two fungi, Trametes versicolor and Stagonospora gigaspora. Trametes versicolor did not cause any depolymerization or degradation of effluent lignins but increased the amount of chromophores, whereas S. gigaspora depolymerized the EOP lignins and caused a substantial reduction in aromatic compounds. For both fungal treatments, CuO oxidation caused a decrease in the yield of the aldehydes within the vanillyl and p-hydroxy phenol families, which was faster than the rates of decrease in the yields of the corresponding acids and ketones. However, only S. gigaspora caused changes in the pattern of the 11 characteristic lignin phenols produced by CuO oxidation, reflecting a preferential metabolism of some phenolic precursors. This fungus decreased the yield of total vanillyl phenols (V), which contributed the bulk of the 11 lignin oxidation products, from 93% initially to 59%. As a consequence, coumaryl (C), syringyl (S), and p-hydroxy phenols (P) became relatively enriched to 1.2, 6.5, and 33%, respectively. The stability of EOP-lignin constituent subunits is S > P > C > V. The two fungi differed significantly in their level of enzyme activities. In effluent-free medium, the ratio of laccase to peroxidase was higher for T. versicolor than for S. gigaspora. The presence of EOP-lignins significantly increased this ratio. No lignin peroxidase was detected but manganese peroxidase and laccase were detected during degradation activities.Key words: lignin phenols, CuO oxidation, laccase, manganese peroxidase, Trametes versicolor, Stagonospora gigaspora

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Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements

Food & Nutrition Research ◽

10.3402/fnr.v55i0.5792 ◽

2011 ◽

Vol 55 (1) ◽

pp. 5792 ◽

Cited By ~ 34

Author(s):

Bente Lise Halvorsen ◽

Rune Blomhoff

Keyword(s):

Lipid Oxidation ◽

Vegetable Oils ◽

Oxidation Products ◽

Omega 3 ◽

Lipid Oxidation Products

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Use of Polymers in Viscosity Index Modification of Mineral Oils and Pour Point Depression of Vegetable Oils

Surfactants in Tribology, Volume 5 ◽

10.1201/9781315120829-6 ◽

2017 ◽

pp. 61-89

Author(s):

Dogan Grunberg ◽

Mert Arca ◽

Dan Vargo ◽

Sevim Z. Erhan ◽

Brajendra K. Sharma

Keyword(s):

Vegetable Oils ◽

Pour Point ◽

Viscosity Index ◽

Mineral Oils

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The effect of dihydroquercetin on the stability of consumer properties of chopped semi-finished meat

E3S Web of Conferences ◽

10.1051/e3sconf/202128505011 ◽

2021 ◽

Vol 285 ◽

pp. 05011

Author(s):

N. N. Shagaeva ◽

S. V. Kolobov ◽

I. A. Zachesova

Keyword(s):

Meat Products ◽

Microbiological Quality ◽

Negative Temperature ◽

Acid Number ◽

Oxidation Products ◽

Raw Material ◽

Experimental Sample ◽

Quality Stability ◽

Increasing Demand ◽

The Stability

The steadily increasing demand for semi-finished meat products is provided by the constantly expanding product range and improving its quality. In turn, quality stability is an important criterion for increasing sales. The article presents data on the effect of a natural antioxidant-dihydroquercetin on the stability of consumer properties of chopped semi-finished moose meat with the addition of beet fiber when stored at a negative temperature for 216 days. Dihydroquercetin was added in an amount of 0.05% by weight of the raw material. In the course of the work, generally accepted methods of studying organoleptic and microbiological quality indicators were used. The degree of oxidative deterioration of the product was checked by determining the acid, peroxide and thiobarbituric numbers. The conducted studies allowed us to conclude that the use of this food additive allows us to preserve the organoleptic and microbiological properties of the semi-finished product for a longer period by inhibiting the formation of oxidation products. The use of dihydroquercetin contributed to a decrease in the experimental sample of the semi-finished product on day 216 of the peroxide and acid number by 2 times, and the thiobarbituric number by 1.8 times in relation to the control. Thus, by reducing the oxidative damage of the semi-finished product, it is possible to influence its characteristics during storage.

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Influence of Oxygen-Containing Sulfur Flavor Molecules on the Stability of β-Carotene under UVA Irradiation

Molecules ◽

10.3390/molecules24020318 ◽

2019 ◽

Vol 24 (2) ◽

pp. 318 ◽

Cited By ~ 1

Author(s):

Gong-Liang Zhang ◽

Hong-Yan Wu ◽

Ying Liang ◽

Jie Song ◽

Wei-Qi Gan ◽

...

Keyword(s):

Sulfur Atom ◽

Critical Role ◽

Oxidation Products ◽

First Order ◽

Uva Irradiation ◽

First Order Kinetics ◽

Dynamic Degradation ◽

The Stability ◽

Ethanol System ◽

Β Carotene

The influence of 11 kinds of oxygen-containing sulfur flavor molecules was examined on β-carotene stability under UVA irradiation in ethanol system. Both the effects of sulfides on dynamic degradation of β-carotene and the relation between structure and effect were investigated. The oxidation products of β-carotene accelerated by sulfides under UVA irradiation were also identified. The results indicated that the disulfides had more obvious accelerative effects on the photodegradation of β-carotene than mono sulfides. The degradation of β-carotene after methyl (2-methyl-3-furyl) disulfide (MMFDS), methyl furfuryl disulfide (MFDS) and bis(2-methyl-3-furyl) disulfide (BMFDS) exposure followed first-order kinetics. Furan-containing sulfides such as MMFDS and BMFDS showed more pronounced accelerative effects than their corresponding isomers. The oxidation products were identified as 13-cis-β-carotene, 9,13-di-cis-β-carotene and all-trans-5,6-epoxy-β-carotene. These results suggest that both the sulfur atom numbers and the furan group in oxygen-containing sulfides play a critical role in the photooxidation of β-carotene.

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