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Ascorbic acid

About: Ascorbic acid is a research topic. Over the lifetime, 93550 publications have been published within this topic receiving 2526817 citations.


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Journal ArticleDOI
TL;DR: Factors which possibly affect the effectiveness of antioxidant protection under oxygen deprivation as well as under other environmental stresses are presented.

3,562 citations

Book ChapterDOI
TL;DR: The method is about seven times as sensitive as the Fiske–SubbaRow procedure and involves less pipetting, but it is not very satisfactory for determining inorganic phosphate if labile phosphate esters are present in large excess.
Abstract: Publisher Summary This chapter discusses the assay of inorganic phosphate, total phosphate, and phosphatases. The phosphomolybdate complex is reduced by ascorbic acid. The method is about seven times as sensitive as the Fiske–SubbaRow procedure and involves less pipetting. One can easily determine 0.01 micromole of phosphate. Pyrophosphate breaks down about 5% in the method and compounds such as glucose 1-phosphate also break down somewhat, so that the method is not very satisfactory for determining inorganic phosphate if labile phosphate esters are present in large excess. The sample of organic phosphate and a drop of magnesium nitrate solution in a small test tube are taken to dryness by shaking the tube in flame. The ashing procedure is rapid and is good for various biological materials and phosphate esters such as nucleic acid, carbohydrate phosphate esters, viruses, and phospholipids. The assay method of phosphatases for inorganic phosphate can be used as an assay for phosphatases hydrolyzing stable phosphate esters such as glucose-6-phosphate, ribose-5-phosphate, and histidinol phosphate. The enzyme incubation can be stopped with the one ascorbic-molybdate solution thus avoiding an extra pipetting.

3,256 citations

Book ChapterDOI
TL;DR: The ferric reducing/antioxidant power (FRAP) assay is a recently developed, direct test of “total antioxidant power” that facilitates experimental and clinical studies investigating the relationship among antioxidant status, dietary habits, and risk of disease.
Abstract: Publisher Summary This chapter discusses ferric reducing/antioxidant power (FRAP) assay. The ferric reducing/antioxidant power (FRAP) assay is a recently developed, direct test of “total antioxidant power.” The FRAP assay is robust, sensitive, simple, and speedy and facilitates experimental and clinical studies investigating the relationship among antioxidant status, dietary habits, and risk of disease. Measurement of the total antioxidant power of fresh biological fluids—such as blood plasma—can be measured directly; the antioxidant content of various dietary agents can be measured objectively and reproducibly and their potential for improving the antioxidant status of the body investigated and compared. The FRAP assay is also sensitive and analytically precise enough to be used in assessing the bioavailability of antioxidants in dietary agents to help monitor longitudinal changes in antioxidant status associated with an increased intake of dietary antioxidants and to investigate the effects of disease on antioxidant status.

3,037 citations

Journal Article
TL;DR: A human model of gastric carcinogenesis with the following sequential stages: chronic gastritis; atrophy; intestinal metaplasia; and dysplasia, which has been linked with the supply of beta-carotene and with excessive salt intake is provided.
Abstract: Evidence from pathology and epidemiology studies has been provided for a human model of gastric carcinogenesis with the following sequential stages: chronic gastritis; atrophy; intestinal metaplasia; and dysplasia. The initial stages of gastritis and atrophy have been linked to excessive salt intake and infection with Helicobacter pylori. The intermediate stages have been associated with the ingestion of ascorbic acid and nitrate, determinants of intragastric nitrosation. The final stages have been linked with the supply of beta-carotene and with excessive salt intake. Nitrosating agents are candidate carcinogens and could originate in the gastric cavity or in the inflammatory infiltrate.

2,959 citations

Journal ArticleDOI
TL;DR: Thermal processing enhanced the nutritional value of tomatoes by increasing the bioaccessible lycopene content and total antioxidant activity and are against the notion that processed fruits and vegetables have lower nutritional value than fresh produce.
Abstract: Processed fruits and vegetables have been long considered to have lower nutritional value than their fresh commodities due to the loss of vitamin C during processing This research group found vitamin C in apples contributed < 04% of total antioxidant activity, indicating most of the activity comes from the natural combination of phytochemicals This suggests that processed fruits and vegetables may retain their antioxidant activity despite the loss of vitamin C Here it is shown that thermal processing elevated total antioxidant activity and bioaccessible lycopene content in tomatoes and produced no significant changes in the total phenolics and total flavonoids content, although loss of vitamin C was observed The raw tomato had 076 +/- 003 micromol of vitamin C/g of tomato After 2, 15, and 30 min of heating at 88 degrees C, the vitamin C content significantly dropped to 068 +/- 002, 064 +/- 001, and 054 +/- 002 micromol of vitamin C/g of tomato, respectively (p < 001) The raw tomato had 201 +/- 004 mg of trans-lycopene/g of tomato After 2, 15, and 30 min of heating at 88 degrees C, the trans-lycopene content had increased to 311+/- 004, 545 +/- 002, and 532 +/- 005 mg of trans-lycopene/g of tomato (p < 001) The antioxidant activity of raw tomatoes was 413 +/- 036 micromol of vitamin C equiv/g of tomato With heat treatment at 88 degrees C for 2, 15, and 30 min, the total antioxidant activity significantly increased to 529 +/- 026, 553 +/- 024, and 670 +/- 025 micromol of vitamin C equiv/g of tomato, respectively (p < 001) There were no significant changes in either total phenolics or total flavonoids These findings indicate thermal processing enhanced the nutritional value of tomatoes by increasing the bioaccessible lycopene content and total antioxidant activity and are against the notion that processed fruits and vegetables have lower nutritional value than fresh produce This information may have a significant impact on consumers' food selection by increasing their consumption of fruits and vegetables to reduce the risks of chronic diseases

2,738 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,743
20223,598
20212,983
20203,510
20193,754
20183,829