Calcium-ascorbic acid concentration

High concentrations of ascorbic acid in brain can be found in catecholamine-rich regions. However, there is no evidence of a close correlation of catecholamines to ascorbic acid (Mefford et al., 1981). The ascorbic acid concentrations of heart, skeletal muscle, and many other organs of vitamin C-dependent vertebrates decreases rapidly in ascorbic acid deficiency. This observation does not hold true for the brain, which shows a very delayed avitaminosis. This indicates an important role of ascorbic acid in neural metabolism. Since ascorbic acid could be determined mainly in neural synapses, it seems evident that the vitamin participates in neurotransmission. In vitro experiments showed that ascorbic acid initiates the calcium-dependent release of acetylcholine (Pinchasi et al., 1979). 

Nutrients frequently consumed in sub-optimal concentrations by humans are proteins, calcium, non, vitamin A, thiamin (vitamin Bl), riboflavin (vitamin B2) and ascorbic acid (vitamin C). Some of these nutrients occur in higher concentrations in fruit juices than hi other foods. There is experimental evidence that indicates that ascorbic acid of natural origin is apparently superior to that of synthetic origin. 

Disposition in the Body. Less than 5% of ingested oxalic acid is absorbed in healthy adults. About 8 to 40 mg of oxalic acid is normally excreted in the urine daily this is derived mainly from the metabolism of dietary ascorbic acid and glycine with small amounts from dietary oxalic acid and other minor metabolic sources. Calcium oxalate is a major constituent of kidney stones and is frequently found as crystals in freshly-voided urine. In normal subjects concentrations of oxalic acid in blood range from about 1 to 3 pg/ml. Small amounts of oxalate are produced as a metabolite of ethylene glycol. 

Bureau of Water Works, Portland, OR Combined chlorine Sodinm bisnlfite Sodium sulfite Sodium thiosulfate Calcium thiosulfate Ascorbic acid Sodium ascorbate 1% solution Stoichiometric concentrations needed for dechlorination 1.1 8.0 Surface water 300... 

When no dechlorination chemical was added, the dissolved oxygen concentration of the released water decreased from an initial concentration of 11 by less than 0.3 mg/L after traveling 450 ft in one test. When stoichiometric amounts of dechlorination chemicals were added, the DO decreased by 1.18,0.3,0.55, and 0.5 mg/L in the presence of sodium metabisulfite, sodium sulfite, sodium thiosulfate, and calcium thiosulfate, respectively. When twice the stoichiometric amounts of dechlorination chemicals were added, the dissolved oxygen concentration decreased hy 1, 0.9, 0.9, and 0.7 mg/L, respectively, in the presence of these chemicals. With the addition of stoichiometric concentrations of ascorbic acid and sodium ascorbate, the DO of the water increased by 0.3 mg/L, after a travel of 450 ft. When twice the stoichiometric concentrations of these chemicals were used, the DO decreased hy 0.2 mg/L. 

In summary, results indicated that sodium metabisulfite had a greater impact (1.0-1.18 mg/L depletion) on the DO concentrations of the water tested. Sodium sulfite, sodium thiosulfate, and calcium thiosulfate decreased the DO concentration hy 0.3-0.9 mg/L, depending on the amount of dechlorination chemical used. Ascorbic acid and sodium ascorbate had the least impact on the DO of the water tested. 

The initial pH of the hydrant water, prior to chemical addition, was between 8.8 and 9.0. Sodium metabisulfite, at either concentration used, decreased the water pH about 0.8 unit after a travel of 450 ft. After a travel of 450 ft, ascorbic acid decreased the pH of the water by 0.3 and 0.6 unit when stoichiometric and twice the stoichiometric amounts, respectively, were used. The pH decreased by less than 0.1 unit when sodium sulfite, calcium thiosulfate, or sodium ascorbate was used at stoichiometric or twice the stoichiometric amounts. 

When no dechlorination chemical was added, the chlorine concentration decreased from 1.05 to 0.95 mg/L after 1000 feet (Fig. 2). This indicated that only a small amount (0.1 mg/L) of the chloramines dissipated through chlorine demand of paved surfaces. Sodium bisulfite, sodium sulfite, ascorbic acid, and sodium ascorbate neutralized all detectable chlorine to below 0.1 mg/L within 2 ft downstream of the mixing hose (approx 2 s). Sodium thiosulfate neutralized more than 80% of the chlorine within 2 ft. However, chlorine concentrations decreased below 0.1 mg/L (the discharge limit in most states) after about 500 ft (elapsed time 3 min, 2 s). Calcium thiosulfate neutralized 60% of the chlorine within 2 ft and neutralized 90% of the chlorine after 1000 ft (elapsed time 7 min, 10s). 

Binding of iron by dietary fiber is strongly inhibited by ascorbic acid, citrate, cysteine, EDTA or phytate in concentrations as lew as 100 >uMols/Liter (A3). The inhibitors have the common property of being able to form soluble complexes with iron. The decarbox-ylic amino acids and their amides inhibit binding moderately as do lysine and histidine. Other amino acids either do not interfere with binding of iron fiber or do so only weakly. Calcium (as acetate) and phosphate act as moderate inhibitors. The detergents sodium lauryl sulfonate or cetyltrimethylammonium bromide had no effect on iron binding by fiber (A2). 

Negative interferences in the tin(II) chloride reduction method may also be caused by the presence of higher concentrations of iron(III), aluminum, calcium, and chloride [100]. The Fe, Al, and Ca interferences are presumably due to competitive complexation of the phosphate, while that for chloride is probably due to inhibition of the phosphomolybdate reduction. The chloride interference in this method is particularly problematic, especially for the determination of phosphate in marine and estuarine waters, and for this reason, the ascorbic acid reduction method of Murphy and Riley [83] is often favored. 

Furfural was found as the main volatile flavor constituent in the fruit of M. emarginata cultivated in Cuba, which was also found to contain over 150 other volatile constituents among them, aliphatic esters (31%), terpenoids (24%), ketones and aldehydes (15%), and alcohols (13%) made up the major components. Miscellaneous constituents include calcium, iron, and phosphorus in comparable concentrations to those of apple /-malic acid dextrose, fructose, and sucrose evidence of a heat-resistant enzyme (not completely deactivated at 103°C) that breaks down ascorbic acid during storage of pasteurized juice, resulting in carbon dioxide buildup, causing swelling of cans or explosion of bottles. 

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