scholarly journals Structure of ascorbic acid and its biological function. Determination of the conformation of ascorbic acid and isoascorbic acid by infrared and ultraviolet investigations

1984 ◽  
Vol 138 (3) ◽  
pp. 479-480 ◽  
Author(s):  
Wolfgang LOHMANN ◽  
Detlef PAGEL ◽  
Volker PENKA
Keyword(s):  
Ascorbic Acid ◽  
Biological Function ◽  
Isoascorbic Acid

Determination of ascorbic acid, dehydroascorbic acid, and isoascorbic acid in blood

1986 ◽  
Vol 325 (5) ◽  
pp. 473-475 ◽  
Author(s):  
Jörg Schreiber ◽  
Wolfgang Lohmann ◽  
Dietrich Unverzagt ◽  
Albert Otten
Keyword(s):  
Ascorbic Acid ◽  
Dehydroascorbic Acid ◽  
Isoascorbic Acid

Differential determination of D-isoascorbic acid and L-ascorbic acid in guinea pig organs

1969 ◽  
Vol 47 (4) ◽  
pp. 449-453 ◽  
Author(s):  
Omer Pelletier
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Synthetic Diet ◽  
Isoascorbic Acid

To test the theory that D-isoascorbic acid (IAA) was not retained by the organs of animals, guinea pigs were fed a synthetic diet containing ascorbic acid (AA) plus IAA. The incorporation of IAA and AA was determined by making use of the different rates of osazone formation of oxidized AA and IAA with 2,4-dinitrophenylhydrazine. It was found that the organs of the guinea pigs retained a significant quantity of IAA which replaced a corresponding quantity of AA. The incorporated IAA could, in turn, be replaced by AA when only AA was subsequently given in the diet.

Structure of Ascorbic Acid and Its Biological Function:

1983 ◽  
Vol 38 (11-12) ◽  
pp. 923-925 ◽  
Author(s):  
W. Lohmann ◽  
J. Winzenburg
Keyword(s):  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Spin Label ◽  
Biological Function ◽  
Ph Value ◽  
Chain Structure ◽  
Side Chain ◽  
Artificial Membrane ◽  
Isoascorbic Acid ◽  
Radical State

It could be shown by the reduction of the spin label (1,14) located within DPPC vesicles, that Na-ascorbate and K-isoascorbate can permeate membranes. At physiologic pH value, these two compounds exist as electroneutral radicals with a cyclic side chain structure. Ascorbic acid and isoascorbic acid, on the contrary, can hardly permeate such an artificial membrane. Since the radical will cause lipid peroxidation, it must be modified prior to permeation. This can be done by GSH which changes the radical state but maintains the electroneutral bicyclic configuration

scholarly journals Simultaneous Determination of Ascorbic, Dehydroascorbic, Isoascorbic, and Dehydroisoascorbic Acids in Meat-Based Food Products by Liquid Chromatography with Postcolumn Fluorescence Detection: A Method Extension

1996 ◽  
Vol 79 (3) ◽  
pp. 803-808 ◽  
Author(s):  
M Sher Ali ◽  
Evan T Phillippo
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Food Products ◽  
Grocery Store ◽  
Homogeneous Sample ◽  
Food Processor ◽  
Isoascorbic Acid ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract A simple and rapid liquid chromatographic (LC) method for determining ascorbic, dehydroascorbic, isoascorbic, and dehydroisoascorbic acids in mostly single-component food products was evaluated for use in analysis of multicomponent meatbased food products such as TV dinners. Groundbeef samples were used as blanks for repeatability studies. Samples were fortified with 5,10,20, and 40 ppm of mixed standards of ascorbic acid and isoascorbic acid. Means of 12 recoveries at 4 levels of fortification were 102.5 and 83.5%, respectively, for ascorbic acid and isoascorbic acid, with coefficients of variation of 6.7 and 15.2%, respectively. TV dinner products (21 samples) from a local grocery store were analyzed for vitamin C content. Samples prepared with a commercial food processor and a food grinder were compared. The commercial food processor was more capable than the food grinder in producing a homogeneous sample, which is critical to the method.

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