ON THE SPECIFICITY OF DYE TITRATION FOR ASCORBIC ACID

1946 ◽  
Vol 24b (1) ◽  
pp. 37-45 ◽  
Author(s):  
Jules Tuba ◽  
George Hunter ◽  
Helen Ruth Steele
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Room Temperature ◽  
Dehydroascorbic Acid ◽  
Usual Method ◽  
Plant Materials ◽  
Treated Plant

The 2,6-dichlorophenolindophenol method of assay of vitamin C has been critically examined with respect to a number of fresh, boiled, and otherwise treated plant materials. Comparative values are given for ascorbic acid as determined by the usual method, for non-vitamin C reductants, and for dehydroascorbic acid.In the fresh uncooked materials examined, non-vitamin C reductants were not found and only in cabbage, peas, and pigweed leaves did dehydroascorbic exceed 10% of the ascorbic acid value.Boiling produced significant amounts of non-vitamin C reductant in cabbage and peas.In rose hips the dye titration gives an accurate measure of ascorbic acid. The amounts of dehydroascorbic acid and non-vitamin C reductant, even under storage at room temperature for over a year, are insignificant.It is concluded that the 2,6-dichlorophenolindophenol method of assay of vitamin C is highly specific but in the case of certain cooked foodstuffs non-vitamin C dye reductants may, without check by other methods, introduce significant errors.

Effect of Dietary Ascorbate on the Concentration of Tissue Ascorbic Acid, Dehydroascorbic Acid, Ascorbic Sulfate, and Activity of Ascorbic Sulfate Sulfohydrolase in Rainbow Trout (Oncorhynchus mykiss)

1990 ◽  
Vol 47 (8) ◽  
pp. 1518-1525 ◽  
Author(s):  
Konrad Dabrowski ◽  
Reinhard Lackner ◽  
Cristine Doblander
Keyword(s):  
Ascorbic Acid ◽  
Rainbow Trout ◽  
Vitamin C ◽  
Oncorhynchus Mykiss ◽  
Dehydroascorbic Acid ◽  
Control Group ◽  
High Demand ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Dietary Treatments ◽  
Kidney Liver

The concentrations of ascorbic acid in several tissues of rainbow trout (Oncorhynchus mykiss) are significantly influenced by various dietary treatments. Ascorbic acid was taken up readily by erythrocytes, kidney, liver, intestine, spleen, and brain in fish fed an ascorbate supplemented diet (AA group), the concentration being from 1.5 to 14.8-fold higher than in fish fed a diet lacking ascorbate (control group). In fish fed a diet supplemented with an equimolar amount of ascorbic acid in the form of ascorbic sulfate (AS group) the ascorbic acid concentrations in kidney, intestine, and erythrocytes were significantly elevated above those of the control group. Ascorbic sulfate was found in kidney, liver, and intestine of the AS group, but not in other groups. In fish fed a diet devoid of vitamin C the ascorbic acid concentrations in kidney, liver, intestine, and spleen were signficantly lower than in fasting fish over the same period of time (28 d), suggesting a high demand for vitamin C in an actively feeding animal. Salmonid fish are therefore probably unable to utilize ascorbic sulfate sufficiently to prevent the appearance of vitamin C deficiency, and thus resemble scurvy-prone mammals in this respect.

scholarly journals Vitamin C and the Role of Citrus Juices as Functional Food

2009 ◽  
Vol 4 (5) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Nuria Martí ◽  
Pedro Mena ◽  
Jose Antonio Cánovas ◽  
Vicente Micol ◽  
Domingo Saura
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Dehydroascorbic Acid ◽  
Antioxidant Response ◽  
Intestinal Wall ◽  
Processing Temperature ◽  
High Concentration ◽  
Citrus Juices ◽  
Citrus Extract

The literature on the content and stability of vitamin C (ascorbic acid, AA) in citrus juices in relation to industrial practices is reviewed. The role of vitamin C from citrus juices in human diet is also reviewed. Citrus fruits and juices are rich in several types of bioactive compounds. Their antioxidant activity and related benefits derive not only from vitamin C but also from other phytochemicals, mainly flavonoids. During juice processing, temperature and oxygen are the main factors responsible for vitamin C losses. Nonthermal processed juices retain higher levels of vitamin C, but economic factors apparently delay the use of such methods in the citrus industry. Regarding packing material, vitamin C in fruit juice is quite stable when stored in metal or glass containers, whereas juice stored in plastic bottles has a much shorter shelf-life. The limiting step for vitamin C absorption in humans is transcellular active transport across the intestinal wall where AA may be oxidized to dehydroascorbic acid (DHAA), which is easily transported across the cell membrane and immediately reduced back to AA by two major pathways. AA bioavailability in the presence of flavonoids has yielded controversial results. Whereas flavonoids seem to inhibit intestinal absorption of AA, some studies have shown that AA in citrus extract was more available than synthetic ascorbic acid alone. DHAA is reported to possess equivalent biological activity to AA, so recent studies often consider the vitamin C activity in the diet as the sum of AA plus DHAA. However, this claimed equivalence should be carefully reexamined. Humans are one of the few species lacking the enzyme (L-gulonolactone oxidase, GLO) to convert glucose to vitamin C. It has been suggested that this is due to a mutation that provided a survival advantage to early primates, since GLO produces toxic H2O2. Furthermore, the high concentration of AA (and DHAA) in neural tissues could have been the key factor that caused primates (vertebrates with relative big brain) to lose the capacity to synthesize vitamin C. Oxidative damage has many pathological implications in human health, and AA may play a central role in maintaining the metabolic antioxidant response. The abundance of citrus juices in the Mediterranean diet may provide the main dietary source for natural vitamin C.

Determination of Total Vitamin C by Ion Exclusion Chromatography with Electrochemical Detection

1989 ◽  
Vol 72 (4) ◽  
pp. 681-686
Author(s):  
Hie-Joon Kim
Keyword(s):  
Ascorbic Acid ◽  
Sulfuric Acid ◽  
Vitamin C ◽  
Retention Time ◽  
Acid Content ◽  
High Speed ◽  
Reference Electrode ◽  
Dehydroascorbic Acid ◽  
Total Vitamin

Abstract A rapid and sensitive liquid chromatographic method for determination of total vitamin C in foods and beverages is described. Ascorbic acid and dehydroascorbic acid are extracted with sulfuric acid solution, and the dehydroascorbic acid in the extract is reduced to ascorbic acid by dithiothreitol at pH 7. The reduction is complete in 2 min at room temperature. The resulting total ascorbic acid is separated on an anion exclusion/high speed column with 20mM sulfuric acid as eluant and detected amperometrically with a platinum electrode operating at +0.6-0.8 V vs Ag/AgCl reference electrode. Dithiothreitol (retention time, 3.2 min) does not interfere with the separation and detection of ascorbic acid (retention time, 1.3 min). The dehydroascorbic acid content can be estimated as the difference in ascorbic acid content measured with and without reduction by dithiothreitol. The completeness of the reduction was demonstrated by purposely allowing the oxidation of ascorbic acid in the food extract and determining the total vitamin C after reduction. The determinations of vitamin C content in selected foods and beverages were in good agreement with the expected values. Total analysis time for vitamin C is 10 min and the detection limit is 0.1 ng. The method is specific for vitamin C, and interference by other food constituents is minimal.

Automated Fluorometric Method for the Determination of Total Vitamin C in Food Products

1976 ◽  
Vol 59 (6) ◽  
pp. 1244-1250 ◽  
Author(s):  
Ram B Roy ◽  
Aldo Conetta ◽  
Jerry Salpeter
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Dehydroascorbic Acid ◽  
Food Products ◽  
Total Vitamin ◽  
Automated Method ◽  
Highly Sensitive ◽  
Aoac Method ◽  
Analytical System

Abstract A specific microfluorometric method for the determination of ascorbic acid, dehydroascorbic acid, and total vitamin C in food products has been automated. The procedure developed is an adaptation of the official AOAC method (secs. 43.056–43.062), except that N-bromosuccinimide is used instead of Norit to oxidize vitamin C. Ascorbic acid is selectively oxidized by N-bromosuccinimide before other interfering substances that may be present, so this method is a highly sensitive and specific technique with extensive applicability. The proposed automated method is simple, rapid, reliable, and sufficiently sensitive to analyze as little as 2 × 10−3 to 0.1 mg ascorbic acid/ml. Analytical results obtained for ascorbic acid, dehydroascorbic acid, and total vitamin C in a wide variety of food products are reported. The analytical system developed has the capability of analyzing 50 samples/hr.

Liquid Chromatography, Microfluorometry, and Dye-Titration Determination of Vitamin C in Fresh Fruit and Vegetables

1983 ◽  
Vol 66 (6) ◽  
pp. 1377-1379
Author(s):  
Ron B H Wills ◽  
Pushparany Wimalasirl ◽  
Heather Greenfield
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Vitamin C ◽  
Dehydroascorbic Acid ◽  
Fresh Fruit ◽  
Fruit And Vegetables ◽  
End Point ◽  
Liquid Chromatographic ◽  
Good Agreement

Abstract The vitamin C content of several fresh fruit and vegetables was determined by a liquid chromatographic (LC) method which gave simultaneous separate values for ascorbic acid and dehydroascorbic acid (DHA) and by the official AOAC methods of microfluorometry and dye-titration. The levels of ascorbic acid obtained by LC and dye-titration were in good agreement, except for a few colored products where it was difficult to determine the end point of the titration. The combined values for ascorbic acid and DHA obtained by LC and microfluorometry were in agreement for most produce, but for about one-third of the samples, the values obtained by microfluorometry were significantly higher.

scholarly journals Dehydroascorbic acid uptake in a human keratinocyte cell line (HaCaT) is glutathione-independent

2000 ◽  
Vol 345 (3) ◽  
pp. 665-672 ◽  
Author(s):  
Isabella SAVINI ◽  
Sylvie DUFLOT ◽  
Luciana AVIGLIANO
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Reductase Activity ◽  
Thioredoxin Reductase ◽  
Dehydroascorbic Acid ◽  
Reduction Process ◽  
Enzymic Activity ◽  
Glutathione Depletion ◽  
Acid Uptake ◽  
Hacat Cells

Vitamin C plays an important role in neutralizing toxic free radicals formed during oxidative metabolism or UV exposure of human skin. This study was performed to investigate the mechanisms that regulate the homoeostasis of vitamin C in HaCaT cells by identifying the events involved in the transport and in the reduction of dehydroascorbic acid. Dehydroascorbic acid accumulated to a greater extent and faster compared with ascorbic acid; its transport appeared to be mediated by hexose transporters and was entirely distinct from ascorbic acid transport. Dehydroascorbate reductase activity was unaffected by glutathione depletion, although it was sensitive to thiol protein reagents. These observations, as well as the subcellular distribution of this enzymic activity and the cofactor specificity, indicate that thioredoxin reductase and lipoamide dehydrogenase play an important role in this reduction process. HaCaT cells were able to enhance their dehydroascorbic acid reductase activity in response to oxidative stress.

scholarly journals The effect of Commercial Practices on Ascorbic Acid and Dehydroascorbic Acid (Vitamin C) in Milk

1940 ◽  
Vol 23 (11) ◽  
pp. 1131-1141 ◽  
Author(s):  
Warren W. Woessner ◽  
K.G. Weckel ◽  
Henry A. Schuette
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Dehydroascorbic Acid

scholarly journals Valuation of α-Fe2O3@C20H38O11 NC Nano-cellulose Surface Coating on Ascorbic Acid Content of Solanum Lycopersicum Under Storage Conditions

2021 ◽  
Author(s):  
Geetika Guleria ◽  
Dhananjay K. Sharma ◽  
Shweta Thakur ◽  
Poonam Kumari ◽  
Mamta Shandilya ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ascorbic Acid ◽  
Klebsiella Pneumoniae ◽  
Vitamin C ◽  
Room Temperature ◽  
Tomato Fruit ◽  
Coating Material ◽  
Tomato Fruits ◽  
Nano Coating ◽  
Nano Cellulose

Abstract Competence of synthesized α-Fe2O3@C20H38O11 NC nano-cellulose antimicrobial coating material and its real-time application to extend storage life of Tomato (Solanum lycopersicum) variety Solan Lalima (India) was studied. Fe2O3 NPs (nanoparticles) were synthesized using a hydrothermal method, and α-Fe2O3@C20H38O11 NC nanocomposite was developed and characterized using XRay Diffractions (XRD) and Scanning Electron Microscopy (SEM) techniques. α-Fe2O3@C20H38O11 NC nanocomposite, and CE (cellulose) were analysed for their antimicrobial activity against Klebsiella pneumoniae and Staphylococcus aureus bacteria. NC exhibit 11mm, 13mm zone of inhibition against Klebsiella pneumoniae and Staphylococcus aureus respectively. Tomato fruit samples coated with (5%) UC1A, UC2A, and (3%) UC1B, UC2B two different concentrations of α-Fe2O3@C20H38O11 NC nanocomposite and uncoated sample UC1, UC2 stored at room temperature (25±2 ºC) and refrigerator temperature (4 oC) respectively for ascorbic acid (vitamin C) analysis on days 0, 4, 8, 12 and 16. Our study revealed that a 3% concentration of α-Fe2O3@C20H38O11 NC nanocomposite material quite potent in maintaining quality aspects of the tomato fruit by no decline of vitamin C under refrigerator conditions up to 16th day. FTIR analysis of all samples was done to determine the functional groups present in tomato samples after storage. AAS (Atomic Absorption Spectrometer) was used to analyse the content of Fe, and Zn elements in tomato samples. This work revealed that the 3% α-Fe2O3@C20H38O11 NC nano-cellulose antimicrobial nano-coating had maintained the quality of the coated tomato fruits and retards microbial growth during storage time and helpful in increasing the shelf life of tomato under cold storage as well as at room temperature. Coating material had not any significant effect on micronutrients element concentrations in both temperature studies. Synthesised α-Fe2O3@C20H38O11 NC antimicrobial nano-coating material can be used effectively for long storage of tomato fruits and safe for dietary intake of human.

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