Fruit sulfiting

It is used to make sulfite paper and other papers, to fumigate fumigant, and to bleach dried fruits. The element is a good insulator. 

Sodium hydrogen sulfite, NaHS03, is a preservative that is used to prevent the discolouration of dried fruit. In aqueous solution, the hydrogen sulfite ion can act as either an acid or a base. Predict whether NaHSOs dissolves to form an acidic solution or a basic solution. (Refer to Appendix E for ionization data.)... 

We have found that HCrOr" in dilute solutions will undergo condensation with hydrogen phosphate, bisulfate, and even hydrochloric acid in water to form these mixed anhydrides like CrSCb-2. We have been able to measure equilibrium constants, and I wondered if this wouldn t prove fruitful in studying such reactions as the oxidation of sulfite with chromate. Sulfite is oxidized to a mixture of dithionate and sulfate. 

It is a common practice to expose many fruits to S02 prior to dehydration. The S02 also extends storage life of raw fruit prior to dehydration. The optimal temperature for exposure to the gas is from 43 to 49VC. Unlike fruit, vegetables are usually dipped in solutions of neutral sulfites and bisulfites. 

Many countries do not allow use of S02 or sulfite salts on meats, fish, piocessed meat and fish products, 01 flesh fruits and vegetables. Where permitted, sulfite is helpful in eliminating black spot formation in shrimp. End-use application of sulfite related compounds as. for example, to prevent discoloration of leafy vegetables on salad bars, is now subject to regulation in the United States. 

Preservatives. Sulfur compounds, such as sulfur dioxide and sodium bisulfite, are used commercially to preserve the color of various food products, such as orange juice, dehydiated fruits and vegetables, such as apricots, carrots, peaches, pears, potatoes, and many odiers. Concentrated sulfur dioxide is used in wine-making to destroy certain bacteria. The color preservation of canned green beans and peas is enhanced by dipping the produce in a sulfite solution prior to canning. In 1986, some of these compounds and uses were put under closer regulation in the United States. 

Federal Register. Sulfiting agents revocation of GRAS status for use on fruits and vegetables intended to be served or sold raw to consumers. 51(131) 25021—25026, 1988. 

Endosulfan [115-29-7] (36) is the adduct of hexachlorocyclopentadiene and l,4-dihydroxy-2-butene which reacts subsequently with SOCl to produce 6>7>8>9>10>10-hexachloro-l,5,5, 6,9,9 -hexahydro-6>9-methano-2,4,3-benzodioxathiepin-3-oxide. The technical product is a brownish solid (mp 70— 100°C, vp 1.3 mPa at 30°C) which consists of about four parts of a-isomer (mp 108°C, cis with regard to the sulfite group) and one part of the p-isomer (mp 206°C, trans with regard to the sulfite group). The a-isomer, which is somewhat more insecticidal, is slowly converted to the more stable p-isomer at high temperature, and both isomers are oxidized slowly to endosulfan sulfate [1031-07-8] (mp 181°C). In acid media, both isomers form endosulfan diol [2157-19-9] (mp 203°C). The rat LDc-s are 43, 18 (oral) and 130, 74 (dermal) mg/kg. Endosulfan is a broad-spectrum insecticide for vegetables, fruits, and row crops. Unlike the other cyclodiene insecticides, it is biodegradable by hydrolysis at the sulfite ester bonds. 

Propaigite [2312-35-8], 2-(/>-/W2-butylphenoxy)cyclohexyl 2-propynyl sulfite (145),is adark oil (d 1.1), is insoluble in water, and hydrolyzes in alkaline solutions. The rat oral LD5Q is 2200 mg/kg. Propargite is a widely used acaricide on fruits, vegetables, and row crops. Oxythioquinox [2439-01-2], 6-methyl-2,3-quinoxalinedithiol cycHc carbonate (146) (mp 172°C, vp 26 fPa at 20°C), is insoluble in water and soluble in organic solvents with rat oral LD5Qs of 1800, 1100 mg/kg. It is used as an acaricide for tree fruits. 

Sulfur dioxide is used for refrigeration and also serves as raw material for the production of sulfuric acid. It is also used as a bleaching agent in the textile and food industries. It is an effective disinfectant and is employed as such for wooden kegs and barrels and brewery apparatus and for the prevention of mold in the drying of fruits. Sulfur dioxide efficiently controls fermentation in the making of wine. It is used in the sulfite process for paper pulp, as a liquid solvent in petroleum refining, and as a raw material in many plants in place of sulfites, bisulfites, or hydrosulfites. 

Histamine may also be released from mastocytes in the gastrointestinal tract induced by aspartame, sodium benzoate, sodium glutamate—which causes Chinese Restaurant Syndrome —and sulfites, which mainly occur in dried fruit and vegetables, marinated vegetables, fruit juices, and low-quality wines (Landete et al., 2005). 

Sulfur dioxide3, sulfite Used as a preservative and antioxidant in wines, dried fruits,... 

Molasses, fruit juice, corns, bagasse, Jerusalem artichockes, cassava, whey, sulfite liquor, saw dust and other wood by-products are used as substrates for alcohol and glycerin production. Starch-based substrates should be first saccharified by amylases prepared from barley, fungi or bacteria. Cellulosic materials must also be chemically or enzymatically hydrolyzed before being used as substrates for alcohol production. Clostridium species contain amylases and are able to convert starch and cellulose directly16). 

Molybdenum plays a role in several enzyme reactions. Some of the molybdenum-containing enzymes are aldehyde oxidase, sulfite oxidase, xanthine dehydrogenase, and xanthine oxidase. This metal is found in cereal grains and legumes leafy vegetables, especially those rich in chlorophyll animal organs and in relatively small amounts, less than 0.1 ppm, in fruits. The molybdenum content of foods is subject to large variations. 

Thiamin is labile to sulfite, which cleaves the methylene bridge. The reaction is slow at acid pH, but rapid above pH 6. Sulfite treatment of dried fruit and other foods results in more or less complete loss of thiamin. 

Sulfur dioxide is used in great quantities in the manufacture of sulfuric acid, sulfurous acid, and" sulfites. It destroys fungi and bacteria, and is used as a preservative in the preparation of dried prunes, apricots, and other fruits. A solution of calcium hydrogen sulfite, Ca(HS03)2, made by reaction of sulfur dioxide and calcium hydroxide. 

Like all sulfites, potassium metabisulfite is not recommended for use in foods that are a source of thiamin, owing to the instability of the vitamin in their presence. Such foods include meat, raw fruits and vegetables, fresh potatoes, and foods that are a source of vitamin B12. A specification for potassium metabisulfite is contained in the Food Chemicals Codex (FCC). 

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