Studies on the Stability of Ascorbic Acid. II. : Identification of Fatty Acid Monoesters of Ascorbic Acid

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

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Label-free proteomic analysis revealed the mechanisms of protein oxidation induced by hydroxyl radicals in whiteleg shrimp (Litopenaeus vannamei) muscle

Food & Function ◽

10.1039/d1fo00380a ◽

2021 ◽

Author(s):

Hui-min Lin ◽

Xue-er Qi ◽

Shan-shan Shui ◽

Soottawat Benjakul ◽

Santiago P. Aubourg ◽

...

Keyword(s):

Ascorbic Acid ◽

Hydroxyl Radicals ◽

Litopenaeus Vannamei ◽

Protein Oxidation ◽

Proteomic Analysis ◽

Muscle Proteins ◽

Label Free ◽

Whiteleg Shrimp ◽

The Stability ◽

Oxidative Effects

The oxidative effects of hydroxyl radicals derived from a FeCl3/ascorbic acid/H2O2 system on the stability of muscle proteins in peeled shrimp (Litopenaeus vannamei) were investigated.

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Complexes of Copper and Iron with Pyridoxamine, Ascorbic Acid, and a Model Amadori Compound: Exploring Pyridoxamine’s Secondary Antioxidant Activity

Antioxidants ◽

10.3390/antiox10020208 ◽

2021 ◽

Vol 10 (2) ◽

pp. 208

Author(s):

Guillermo García-Díez ◽

Roger Monreal-Corona ◽

Nelaine Mora-Diez

Keyword(s):

Antioxidant Activity ◽

Ascorbic Acid ◽

Rate Constant ◽

Stable Complex ◽

Aqueous Environment ◽

Oh Radicals ◽

Bidentate Ligands ◽

Superoxide Radical Anion ◽

Amadori Compound ◽

The Stability

The thermodynamic stability of 11 complexes of Cu(II) and 26 complexes of Fe(III) is studied, comprising the ligands pyridoxamine (PM), ascorbic acid (ASC), and a model Amadori compound (AMD). In addition, the secondary antioxidant activity of PM is analyzed when chelating both Cu(II) and Fe(III), relative to the rate constant of the first step of the Haber-Weiss cycle, in the presence of the superoxide radical anion (O2•−) or ascorbate (ASC−). Calculations are performed at the M05(SMD)/6-311+G(d,p) level of theory. The aqueous environment is modeled by making use of the SMD solvation method in all calculations. This level of theory accurately reproduces the experimental data available. When put in perspective with the stability of various complexes of aminoguanidine (AG) (which we have previously studied), the following stability trends can be found for the Cu(II) and Fe(III) complexes, respectively: ASC < AG < AMD < PM and AG < ASC < AMD < PM. The most stable complex of Cu(II) with PM (with two bidentate ligands) presents a ΔGf0 value of −35.8 kcal/mol, whereas the Fe(III) complex with the highest stability (with three bidentate ligands) possesses a ΔGf0 of −58.9 kcal/mol. These complexes can significantly reduce the rate constant of the first step of the Haber-Weiss cycle with both O2•− and ASC−. In the case of the copper-containing reaction, the rates are reduced up to 9.70 × 103 and 4.09 × 1013 times, respectively. With iron, the rates become 1.78 × 103 and 4.45 × 1015 times smaller, respectively. Thus, PM presents significant secondary antioxidant activity since it is able to inhibit the production of ·OH radicals. This work concludes a series of studies on secondary antioxidant activity and allows potentially new glycation inhibitors to be investigated and compared relative to both PM and AG.

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Pulsed Infrared Roasting of Groundnuts and its Quality

International Journal of Food Engineering ◽

10.2202/1556-3758.1158 ◽

2009 ◽

Vol 5 (4) ◽

Cited By ~ 5

Author(s):

Sanjeet Kumar ◽

Sukumar Debnath ◽

Umesh H Hebbar

Keyword(s):

Fatty Acid ◽

Free Fatty Acid ◽

Product Quality ◽

Free Fatty Acid Content ◽

Acid Content ◽

Fatty Acid Content ◽

Central Composite Rotatable Design ◽

The Stability ◽

Central Composite ◽

Sand Roasting

The application of high intensity, pulsed infrared radiation for roasting of groundnuts is attempted and the product quality is compared with that of the conventionally roasted samples. Product qualities such as lightness (color), compressive strength (texture) and free fatty acid content are analyzed for different combinations of roasting duration (4-12 min) and temperature (160-200°C), selected based on central composite rotatable design (CCRD). Pulsed infrared roasting at 178-188°C for 6.8-9.2 min resulted in optimum product quality in terms of color, texture and free fatty acid content. The other parameters such as oil and moisture content, peroxide value and sensory characteristics of roasted nuts are also evaluated for the select temperature-duration combinations. The oil yield increased marginally with roasting duration and temperature. Peroxide number, an indicator of the stability of fat, did not vary during infrared roasting. Groundnuts processed at 180°C for 8 min scored high in terms of sensory attributes. Infrared roasting resulted in better product quality as compared to drum and sand roasting.

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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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The stability of Fe(III)-As(V) co-precipitate in the presence of ascorbic acid: Effect of pH and Fe/As molar ratio

Chemosphere ◽

10.1016/j.chemosphere.2018.11.142 ◽

2019 ◽

Vol 218 ◽

pp. 670-679 ◽

Cited By ~ 3

Author(s):

Zidan Yuan ◽

Guoqing Zhang ◽

Jinru Lin ◽

Xiangfeng Zeng ◽

Xu Ma ◽

...

Keyword(s):

Ascorbic Acid ◽

Molar Ratio ◽

Effect Of Ph ◽

Acid Effect ◽

The Stability

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On the stability of ascorbic acid in emulsified systems for topical and cosmetic use

International Journal of Pharmaceutics ◽

10.1016/s0378-5173(99)00228-8 ◽

1999 ◽

Vol 188 (2) ◽

pp. 233-241 ◽

Cited By ~ 163

Author(s):

M. Gallarate ◽

M.E. Carlotti ◽

M. Trotta ◽

S. Bovo

Keyword(s):

Ascorbic Acid ◽

The Stability

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Effect of Post-Treatments on the Stability of the Langmuir–Blodgett Film of Fatty Acid Salt in Vacuum

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.60.3808 ◽

1987 ◽

Vol 60 (10) ◽

pp. 3808-3810 ◽

Cited By ~ 1

Author(s):

Makio Iwahashi ◽

Yoshimi Yamaguchi ◽

Koichi Kobayashi ◽

Tsutomu Seimiya

Keyword(s):

Fatty Acid ◽

Acid Salt ◽

Fatty Acid Salt ◽

Blodgett Film ◽

Langmuir Blodgett ◽

Langmuir Blodgett Film ◽

The Stability

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The effect of freezing-drying, cloudiness and concentration on the keeping quality of various blackcurrant products

Agricultural and Food Science ◽

10.23986/afsci.71612 ◽

1964 ◽

Vol 36 (1) ◽

pp. 161-180

Author(s):

Taina Kuusi

Keyword(s):

Ascorbic Acid ◽

Relevant Literature ◽

Organoleptic Properties ◽

Black Currant ◽

Organoleptic Evaluation ◽

Freeze Dried ◽

Juice Concentrate ◽

The Stability ◽

And Storage

Experiments have been made in the development of various new black-currant products, such as cloudy juice, juice concentrate and various freeze-dried preparations, along with a study of the effect of these different methods of preparation on the initial quality and storage properties. The quality was assessed from the stability of ascorbic acid and colour, the aroma number, and organoleptic evaluation. Storage lasted up to 8 months. It was established that the cloudiness exercised a slight protective effect on ascorbic acid. However, the instability of the cloud meant that the appearance of the cloudy juice was less attractive than that of the clear juice. No well-founded advantage of the cloudy juice could be demonstrated. Concentration proved less suitable, as there occurred harmful changes in ascorbic acid, colour and organoleptic properties. The freezing-drying method was excellent with respect to ascorbic acid and colour. In contrast, considerable losses in aroma occurred, with consequent weakening of the organoleptic properties. This method would be of advantage only in combination with aroma recovery, and solution of the financial problems involved. The results are discussed in the light of relevant literature.

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