Acid foods

Acid foods generally require the simplest equipment for heat preservation. The food can be heated to 100°C and filled hot into suitable containers. The containers are sealed, inverted to sterilize the closure, held at the filling temperature for a short time to ensure that the package is thoroughly heated, and then cooled. Tomato sauces, jellies, fmits, fmit juices (qv), and pickles are routinely preserved in this fashion. 

The effect of various pHs has been well known for some time. Acidic foods such as fmits tend to retard microbial growth and resist certain types of contamination. For this reason, the standards adopted industry-wide have been based on the processing of foods of high acidity (low pH). In the United States, the FDA has regulatory responsibiUty over the preparation, sterilization, and distribution of foods. 

Sulfuric Acid, Food Chemicals Codex, National Academy Press, Washington, D.C., 1981, pp. 317—318. 

Board, P. W. and Elbourne, R. G. P., Pitting Corrosion in Plain Cans Containing Acid Foods , Food Techno ., 19, 1571 (1965) C.A., 64, 2661c Voogel, P., Pit Corrosion of Internally Painted Cargo and Cargo/Ballast Tanks of Oceangoing Crude Oil Tankers , J. Oil Colour Chemists Assoc., 48, 597 (1965)... 

In plain tinplate cans for acid foods, tin provides cathodic protection to steel (3,4). The slow dissolution of tin prevents steel corrosion. Many investigators (5-1I) have defined this mechanism in detail and have shown that the tin dissolution rate is a function of the cathodic activity of the base steel, the steel area exposed through the tin and the tin-iron alloy layers, and the stannous ion concentration. Kamm et al. showed that control of the growth of the tin—iron alloy layer provides a nearly continuous tin-iron alloy layer and improves the corrosion resistance of heavily coated (over 45 X 10"6 in. tin) ETP for mildly acid food products in which tin provides cathodic protection to steel (12). The controlled tin-iron alloy layer reduces the area of steel exposed to the product. ETP with the controlled alloy is designated type K, and since 1964, 75 type K ETP has been used to provide the same protection as 100 ETP provided previously (13). 

The new continuous casting processes, in contrast to ingot cast products, provide tin mill products which are exceptionally clean and formable. The deoxidizing processes required for continuous casting involve either aluminum or silicon killing, which adds aluminum or silicon to the steel. Experience with type D steels indicates that the added aluminum will not cause a corrosion problem. Laubscher and Weyandt (18) have shown that the silicon found in silicon killed, continuous cast, heavily coated ETP will not adversely affect the corrosion performance of plain cans packed with mildly acid food products in which tin usually protects steel. The data on enameled cans is not definitive. Additional published data are required to determine whether or not silicon actually reduces the performance of enameled cans made from enameled, heavily coated, silicon killed, continuous cast ETP. 

Sodium benzoate is used in acidic foods and products to control bacteria, mold, yeasts, and other microbes. It interferes with their ability to make energy. 

Garcia-Viguera, C. and Bridle, R, Influence of structure on colour stability of anthocyanins and flavylium salts with ascorbic acid, Food Chem., 64, 21, 1999. 

Oxidation ol glucose Pd-Bi/C Glulonic acid Food, detergents, pharma... 

Levodopa, a dopamine precursor, is the most effective agent for PD. Patients experience a 40% to 50% improvement in motor function. It is absorbed in the small intestine and peaks in the plasma in 30 to 120 minutes. A stomach with excess acid, food, or anticholinergic medications will delay gastric emptying time and decrease the amount of levodopa absorbed. Antacids decrease stomach acidity and improve levodopa absorption. Levodopa requires active transport by a large, neutral amino acid transporter protein from the small intestine into the plasma and from the plasma across the blood-brain barrier into the brain (Fig. 29-2). Levodopa competes with other amino acids, such as those contained in food, for this transport mechanism. Thus, in advanced disease, adjusting the timing of protein-rich meals in relationship to levodopa doses may be helpful. Levodopa also binds to iron supplements and administration of these should be spaced by at least 2 hours from the levodopa dose.1,8,16,25... 

Bacteria not only attack teeth but can also make people extremely sick. Therefore, canned food must be specially prepared to prevent the growth of bacteria. This is usually done by boiling or steaming. People who can their own food at home, however, do not have the sophisticated machines that food-canning manufacturers have. Even so, there are other methods that home canners can use to preserve their own food and keep their families safe. For example, high heat can be used to kill the bacteria Clostridium botulinum, which causes one deadly form of food poisoning called botulism. Acidic conditions will also kill C. botulinum. Because the bacteria cannot survive at a pH below 4.5, very acidic foods such as tomatoes, pears, and peaches are safe for home canning. 

De Menezes, H. C., The relationship between the state of maturity of raw coffee beans and the isomers of caffeoylquinic acid, Food Chem. 50(3),293, 1994. (CA121 33749w)... 

Why Should You Avoid Acidic Foods When Taking Penicillin ... 

Why should you avoid acidic foods when taking penicillin See p. 178. 

Piper, P., Calderon, C.O., Hatzixanthis, K. and Mollapour, M. (2001) Weak acid adaptation the stress response that confers yeasts with resistance to organic acid food preservatives . 

Vrchovska V, Sousa C, Valentao P, Ferreres F, Pereira JA, Seabra, RM and Andrade PB. 2006. Antioxidative properties of tronchuda cabbage (Brassica oleracea L. var. costata DC) external leaves against DPPH, superoxide radical, hydroxyl radical and hypochlorous acid. Food Chem 98(3) 416-425. 

Luo Y and Barbosa-Canovas GV. 1997. Enzymatic browning and its inhibition in new apple cultivar slices using 4-hexylresorcinol in combination with ascorbic acid. Food Sci Technol Int 3 195-201. 

In bakery products the pH of the product is important for several reasons. Acid foods are normally relatively safe microbiologically as a low pH inhibits the growth of bacteria. Fruit flavoured products such as fruit pie fillings normally have some acid component added to complement the fruit flavour. Where a hydrocolloid is present the pH of the product can be critical in terms of product stability or gelling. A hydrocolloid held at its isoelectric point, i.e. the pH at which there is no net charge, will likely come out of solution. 

A stable foam is likely to have ingredients that are in a low energy state at the air-liquid interface. Substances that fit this description include proteins, emulsifiers some fats and fat components such as diglycerides monoglycerides and fatty acids. Food law uses the term emulsifier and stabiliser to cover the situation where the ingredient is stabilising an emulsion rather than helping to form it. 

It is an anaerobic, gram-positive, spore-forming, rod-shaped bacterium that produces neurotoxins (see C16-A005), especially in low-acid foods. The natural reservoir is soil. It is also found in honey. This is a biosafety level 2 agent. 

Acid dye affinity, 19 759 Acid dyes, 9 184-186, 189-190, 215-216, 226, 243 26 395-396 anthraquinone, 9 301, 327-329 azo, 9 389-394 Acid dyestuffs, 9 223 Acid extractants, 10 750 Acid fixing reactive dyes, 9 478-481 Acid foods, heat preservation of, 12 80 Acid functional polyesters, 10 402 Acid gas constituents, 12 376-378 Acid gases, 10 612-613... 

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