abstract this experiment was carried out to determine the effects of proline and ascorbic acid on chilling injury, electrolyte leakage, lipid peroxidation, peroxide hydrogen and antioxidant enzymes activity of thompson grape (vitis vinifera l.) fruit. grape fruits were treated by 0 (control), 250 and 500 µm proline and 0 (control), 2 and 4% ascorbic acid and their combinations, then stored at 1...

It is well known that the determination of ascorbic acid in urine by titration with 2,6dichlorophenol indophenol in acid solution is not a specific method. Various interfering substances have been reported, such as sulfhydryl compounds (l), thiosulfate (2), and pyridium (medication) (3). The same limitations apply to other oxidation-reduction methods, except when the reducing substance is deter...

Dehydro-L-ascorbic acid, the oxidation product of L-ascorbic acid, is unstable in aqueous solution and decomposed by a hydrolytic disruption of its ring structure to 2,3-diketo-L-gulonic acid. It is shown by means of UV, 'H-, and 13C-NMR spectroscopy that after decarboxylation 3,4,5-trihydroxy-2-keto-L-valeraldehyde, an a-ketoaldehyde, is formed. This substance is oxidized further to L-erythroa...

At present, it is widely-known that free radicals are the causes of illness such as cancers, coronary heart disease, Alzheimer’s disease and aging. One method of protection from free radical is the consumption of antioxidant-containing foods or herbs. Several analytical methods have been used for qualitative and quantitative determination of antioxidants. This project aimed to evaluate antioxid...

It is known that, of all animal species studied, only man, other Primates, and the guinea pig are unable to synthesize ascorbic acid. Results obtained in rats, with radioactive glucose, indicate that ascorbic acid is synthesized by a fairly direct route from glucose (l-3), but no information has been available concerning the rate of synthesis and metabolism of ascorbic acid. Such information wo...

Ochromonas danica Pringsheim, a freshwater chrysomonad, converts d-glucose into l-ascorbic acid over a metabolic pathway that ;inverts' the carbon chain of the sugar. In this respect, l-ascorbic acid formation resembles that found in ascorbic acid-synthesizing animals. It differs from this process in that d-galacturonate and l-galactono-1,4-lactone, rather than d-glucuronate and l-gulono-1,4-la...

Gold and glassy carbon electrode surfaces were modified with L-cysteine, the electrochemical behavior of ascorbic acid (AA) was investigated on these new surfaces. To improve efficiency electrodes, optimum conditions for AA determination established. Electrochemical experiments performed at different potential ranges, concentration AA, scan rates, number polymerization cycles pH values. Using c...

The electrochemical behavior of ascorbic acid and rutin using a poly(L-arginine)-graphene oxide modified glassy carbon electrode (PLA-GO/GCE) has been studied by cyclic voltammetry and chronoamperometry. The modified electrode succeeds in distinguishing the electrochemical responses of ascorbic acid and rutin in a mixture solution due to its high electron transfer rate and good catalytic abilit...

The inhibiting effect of ascorbic acid, citric acid and sodium chloride on Polyphenoloxidase (PPO) of Golden Delicious apple cubes was studied. Dipping in ascorbic acid (0.2-10 g/L range) and in NaCl (0.2-1 g/L range) solutions for 5 min increases the PPO activiry. Citric acid solutions (0.2-10 g / L range) have little or no inhibition of PPO. A 90-100% PPO inhibition was obtained with a 5 min ...