Buffers in foods

Concentrating phosphoric acid leads to polyphosphoric acid, a mixture of several polymeric species, a good catalyst and dehydrating agent. Polyphosphate salts are used as water softeners in detergents or as buffers in food. Small quantities of elemental phosphorus are used to make matches, and phosphorus halides to prepare specialty chemicals for the pharmaceutical and agrochemical industries. 

Use Baking powders, fertilizers, mineral supplement, stabilizer for plastics, to control pH in malt, glass manufacture, buffer in foods, firming agent. 

Use Medicine (antacid), sequestrant, stabilizer, buffer in foods. 

Uses Organic synthesis biochemical research infusion sol ns. chicken-feed additive nutrient, dietary supplement, buffer in foods and pharmaceuticals flavor modifier, sweetener in foods reduces bitter taste of... 

Citric acid is utilized in a large variety of food and industrial appHcations because of its unique combination of properties. It is used as an acid to adjust pH, a buffer to control or maintain pH, a chelator to form stable complexes with multivalent metal ions, and a dispersing agent to stabilize emulsions and other multiphase systems (see Dispersants). In addition, it has a pleasant, clean, tart taste making it useful in food and beverage products. 

As was indicated, there have not been a large number of publications on the CE analysis of methylxanthines in food systems. Analusis published a method using a 20-mm Borate buffer at pH 9.6 and UV detection at 254 nm and +22 kV applied voltage.41 Samples were diluted and prepared for analysis by filtration and analyzed using free solution electro-... 

A buffer comprises (1) a weak acid and a salt of that acid, (2) a weak base and a salt of that base, or (3) it may contain an acid salt. We define an acid-base buffer as a solution whose pH does not change after adding (small amounts of) a strong acid or base . Sodium ascorbate is a favourite buffer in the food industry. 

Monobasic calcium phosphate is primarily used in fertilizers. It also is used in baking powders as a mineral supplement in food as a buffer for pH control and as a stabilizer for plastics. 

Monobasic sodium phosphate is used in baking powders, acid cleansers, electroplating, as a dry acidulant, and in treating boiler water. It also is a nutrient supplement in food. It is a laboratory reagent used as a buffer. 

AOAC International. (1995). AOAC Method 991.43, Total, Insoluble and Soluble Dietary Fiber in Food—Enzymatic-Gravimetrie Method, MES-TRIS Buffer. Official Methods of Analysis, 16th ed., Gaithersburg, MD. 

Folate is a relatively unstable nutrient processing and storage conditions that promote oxidation are of particular concern since some of the forms of folate found in foods are easily oxidized. The reduced forms of folate (dihydro- and tetrahydrofolate) are oxidized to p-aminobenzoylglutamic acid and pterin-6-carboxylic acid, with a concomitant loss in vitamin activity. 5-Methyl-H4 folate can also be oxidized. Antioxidants (particularly ascorbic acid in the context of milk) can protect folate against destruction. The rate of the oxidative degradation of folate in foods depends on the derivative present and the food itself, particularly its pH, buffering capacity and concentration of catalytic trace elements and antioxidants. 

The TSP interface is widely used for tlie determination of drug residues in foods (86). TSP is typically used with reversed-phase columns and volatile buffers. 

Phosphate buffers are most frequently used to dissolve food proteins because they mostly exist in food systems at neutral pH and because of the strong buffering capacity of phosphate buffers at broad pH ranges. 

Development of fast, accurate, and reproducible high-performance liquid chromatography (HPLC) methods has offset the use of traditional open-column and TLC methods in modern chlorophyll separation and analysis. A number of normal and reversed-phase methods have been developed for analysis of chlorophyll derivatives in food samples (unit F4.4), with octadecyl-bonded stationary phase (C]8) techniques predominating in the literature (Schwartz and Lorenzo, 1990). Inclusion of buffer salts such as ammonium acetate in the mobile phase is often useful, as this provides a proton equilibrium suitable for ionizable chlorophyllides and pheophorbides (Almela et al., 2000). 

Ethoxyquin, a synthetic antioxidant, is not generally allowed for human consumption in foods, but it is being added to animal feed and to fruits as an antiscald agent (94,143). Ethoxyquin is also used in the spice industry to prevent carotenoid loss during postharvest handling. However, ethoxyquin-treated paprika is unacceptable for some markets and some consumers (129). Perfetti et al. (130) described a method for determination of ethoxyquin in paprika and chili powder. Ethoxyquin was extracted from the spice with hexane and partitioned into 0.3 N HC1. After adjusting the solution to pH 13-14, ethoxyquin was extracted into hexane, and the hexane layer was evaporated to dryness. An acetonitrile solution of the residue was then analyzed by reversed-phase HPLC, with detection at 254 nm. The mobile phase was water/acetonitrile with ammonium acetate buffer. Recoveries from samples fortified at 50, 100, and 200 ppm averaged 92%, with a coefficient of variation of 2.3%. The method was applied to a number of commercial samples of paprika and chili powder. Ethoxyquin was found in paprika samples at levels up to 63 ppm and in chili powder samples at levels up to 20 ppm. 

Most of the LC-MS assays for the determination of TCs in food samples were based on a sample homogenization/precipitation with Mcllvaine-EDTA buffer followed by SPE on a C18 cartridge. Only one paper presented a combination of MCAC assay with LC-MS analysis (28) thus, it was reviewed in the previous section. 

Aluminum compounds are used in many diverse and important industrial applications such as alums in water-treatment and alumina in abrasives and furnace linings. They are found in consumer products such as antacids, astringents, buffered aspirin, food additives, and antiperspirants. Powdered aluminum metal is often used in explosives and fireworks. To learn more about the properties and uses of aluminum, see Chapters 3 and 4. 

---