Calcium in milk

Covers, M. J., Termont, D. S., Lapre, J. A., Kleibeuker, J. H., Vonk, R. J., and van der Meer, R. (1996). Calcium in milk products precipitates intestinal fatty adds and secondary bile acids and thus inhibits colonic cytotoxicity in humans. Cancer Res. 56,3270-3275. 

The pH and the concentration of calcium in milk also vary, with consequential effects on the properties of renneted milk gels. The addition of CaCl2 to cheesemilk (0.02%) is widely practised and adjustment and standardization of milk pH by using the acidogen, gluconic acid-5-lactone (GDL), is recommended and commercially practised on a limited scale. 

Nickerson, T. A., Moore, E. E. and Zimmer, A. A. 1964. Spectrophotometric determination of calcium in milk using 2,2 -(ethanediylidene-dinitrilo) diphenol (glyoxal bis (2-hydroxyanil). Anal. Chem. 36, 1676-1677. 

Jaynes, H. 0. and Whitney, R. McL. 1982. Resin-contact time for the determination of protein bound calcium in milk and model systems. J. Dairy Sci. 65, 1074-1083. 

Yamauchi, K., Yoneda, Y., Koga, Y. and Tsugo, T. 1969. Exchangeability of colloidal calcium in milk with soluble calcium. Agr. Biol Chem. 33, 907-914. 

The bioavailability of calcium from dairy foods is considered to be excellent (Schaafsma 1983). Evidence from animal studies suggests that the form of calcium in dairy foods may influence the bioavailability of this mineral (Wong and LaCroix 1980). For example, dairy foods that contain colloidal calcium phosphate or calcium caseinate (e.g., as in Cheddar cheese) appear to be somewhat better sources of calcium than foods that contain ionic calcium (e.g., yogurt, buttermilk). However, calcium in milk and other milk products is of greater bioavailability to humans than calcium found in other food sources. According to Renner (1983), calcium utilization from skim milk powder is 85% compared with 22-74% from vegetables. Dietary fiber in plant cell... 

J. F. van Staden, A. van Rensburg, Simultaneous determination of total and free calcium in milk by flow injection, Analyst, 115 (1990), 605-608. 

Not one of these four traits for organization is evident. This essay begs the question Why construct a graphic organizer and a 1-2-3 map if you don t intend to follow it The student s statements, especially those made about milk, are written in a very arbitrary way information about the calcium in milk is in the last sentence when several sentences earlier, the student informed the reader about the protein in milk. Didn t he remember that his 1-2-3 map was constructed to remind him that he needed to restate his objective It wasn t about milk and calcium. 

The methods involving GBHA have been applied for determining calcium in milk [68], soil, plant material, and natural waters [69], uranium [70], silicate minerals [71], and lithium and barium salts [27]. 

Figure 3.4 Data from 10 measurements of calcium in milk by EDTA titration. The outlier is circled. The solid line is the mean of the data (x) and the dashed line is at x + Gcriticai > where s is the standard deviation of the data and Gcrideal = 2.29, which is the two-tailed G value at a = 0.05.

Table 3.4 Replicate results for the measurement of calcium in milk by two methods...

The probability of the data given that there is no difference between the methods is 0.0275. Therefore we conclude that there is a significant difference in the analytical result obtained with the AAS method of analysis of calcium in milk and the complexo-metric titration method. 

Table 5.2 Calibration of an absorbance method for the analysis of calcium in milk...

W. D. Basson and J. F. van Staden, Direct Determination of Calcium in Milk on a Non-Segmented Continuous Flow System. Analyst, 104 (1979) 419. 

Generally, seaweed contains high ash content indicating appreciable amounts of minerals. Mineral content of seaweed can account for up to 36% of its dry mass and mineral macronutrients include sodium, calcium, magnesium, potassium, chlorine, sulfur, and phosphorus whereas the micronutrients include iodine, iron, zinc, copper, selenium, molybdenum, fluoride, manganese, boron, nickel, and cobalt. Among these minerals, calcium holds 4-7% of dry matter. At 7% calcium, a t) ical daily portion size of seaweed (8 g dry weight) provides 560 mg of calcium which is a considerable amount compared to its recommended daily allowance (800-1000 mg) (Anonymous, 2004). In seaweeds, calcium is available as calcium phosphate, and that is more bioavailable than the form of calcium in milk, which is calcium carbonate. 

The newest studies indicate that calcium in milk may be beneficial. It is thought that calcium helps to neutralize the effect of oxalates, the chemicals that are thought to initiate the formation of kidney stones in some people. Oxalates are in fruits, vegetables, whole grains, and beans. When the foods that contain oxalates are consumed with milk, the calcium in the milk binds with the oxalates, and allows the food to go through the body without absorbing the oxalates. In this manner the risk of kidney stones is reduced. 

The proposed reason for these changes is that the calcium in milk and yoghurt or other dairy products combines with the ciprofloxacin and norfloxacin to produce insoluble chelates. Compare also Quinolones -i-Antacids or Calcium compounds , p.328. 

There seem to be no direct clinical studies with calcium-containing antacids, but a clinically important interaction seems almost a certainty, based on in vitro studies with calcium carbonate, calcium in milk, (see Tetracyclines + Food or Drinks , p.347), dicalcium phosphate, and calcium as an excipient in tetracycline capsules. 

Other potential sources of interference are the sample matrix and the solvent used for making the sample solution. The sample matrix is anything in the sample other than the analyte. In some samples, the matrix is quite complex. Milk, for example, has a matrix that consists of an aqueous phase with suspended fat droplets and suspended micelles of milk protein, minerals, and other components of milk. The determination of calcium in milk presents matrix effects that are not found when determining calcium in drinking water. Sample solutions with high concentrations of salts other than the analyte may physically trap the analyte in particles that are slow to decompose, interfering in the vaporization step and causing interference. Differences in viscosity or surface tension between the standard solutions and the samples, or between different samples, will result in interference. Interference due to viscosity or surface tension occurs in the nebulization process for FAAS... 

Nordbd R (1939) The concentration of ionized magnesium and calcium in milk. J Biol Chem 128 745-757... 

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