Indirect Addition

Yeast is propagated at 25-27 °C in a weU-aerated liquid pre-ferment which contains flour, water and some sugar. After a given time, the liquid is blended with the bulk of flour and water and other ingredients and then made into a dough in a mixer. 

For continuous indirect addition of yeast, special liquid starters (sponges) with a pH of 5.0-5.3 are also used with incubation at 38 °C to develop aroma. Such matured fermented sponge is then metered continuously into a kneader which handles the dough. 

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A number of antioxidants have been accepted by the FDA as indirect additives for polymers used in food appHcations. Acceptance is deterrnined by subchronic or chronic toxicity in more than one animal species and by the concentration expected in the diet, based on the amount of the additive extracted from the polymer by typical foods or solvents that simulate food in their extractive effects. Only materials of insignificant risk to the consumer are regulated by the FDA for use in plastics contacted by food stuffs. 

Like alkenes (Sections 7.4 and 7.5), alkynes can be hydrated by either of two methods. Direct addition of water catalyzed by mercury(II) ion yields the Markovnikov product, and indirect addition of water by a hydroboration/ oxidation sequence yields the non-Markovnikov product. 

Substances prohibited from indirect addition to human food through food-contact surfaces Lead solder 29CFR 189.240 FDA 1995... 

FDA. 1995. Substances prohibited from use in human food. Substances prohibited from indirect addition to human food through food-contact surfaces. U.S. Food and Drug Administration. Code of Federal Regulations. 21 CFR 189.240. 

The definition of a food additive in Section 201(s) of the Federal Food, Drug, and Cosmetic Act, as amended ( the Act ) refers to substances whose intended use results directly or indirectly in the substance becoming a component of food. The FDA refers to direct food additives as those added to a food to accomplish an intended effect. Indirect additives are those that unintentionally, though predictably, become components of food. Components of plastic packaging materials that can migrate to food are indirect additives. 

These are good dienophiles. and aryl vinyl sulfones have found use as equivalents of ethylene and ketene through functional modifications of their adducts. However, as the base-induced elimination of a sulfinic acid to yield an olefin occurs only with difficulty, they are not direct precursors of acetylene equivalents, unless suitably modified as in ( )-l-phenyl-sulfonyl-2-trimethylsilyl ethylene (PhS02-CH=CH-TMS). In its cycloadducts the elimination to an alkene is smoothly realized by the fluoride ion. If an alkylation step is previously carried out on the adduct, the overall process realizes an indirect addition of a terminal acetylene, as in the examples given here [533]. 

The use of antioxidants in foods, pharmaceuticals, and animal feeds (direct feed additives), as well as their use in food-contact surfaces (indirect additives) is closely regulated by the governments of several countries. Antioxidants are approved only after extensive extraction, toxicological, and feeding studies. The list is relatively limited. Although antioxidants have been used for several decades and some occur naturally in food substances, intensive lesearch in continuing, pardy accelerated by the growing use of unsaturated oils in numerous food products. 

The plastics industry is mainly concerned with the Bureau of Foods which conducts research and develops standards on the composition, quality, nutrition, and safety of foods, food additives, colors and cosmetics, and conducts research designed to improve the detection, prevention, and control of contamination. The FDA is concerned about indirect additives. Indirect additives are those substances capable of migrating into food from contacting plastic materials. Extensive tests are carried out by the FDA before issuing safety clearance to any plastic... 

In summary, the T-taxol conformation is the only one that is compatible with the EC density and with the intemuclear distances measured by REDOR ss-NMR. The conformation of T-taxol has been used as a template to design novel bridged taxanes. The fact that some of them possess improved bioactivity [89, 90] provides indirect additional evidence that T-taxol represents indeed the bioactive conformation. 

Quaternary ammonium salts of such bases could be prepared only indirectly addition of bromine to l-dimethylamino-4-pentene, followed by removal of hydrogen bromide, afforded—according to the dehydrohalogenation conditions—quaternary ammonium salts (53 or 54) derived from 1,2-dimethyl-d2-pyrroline or l-methyl-2-methy lenepyrrolidine.225... 

Also included in this experiment is a procedure for the analysis of direct and indirect additives in beverages and soft drinks (Sections E-G). This analysis may be substituted for the APC procedure if the instructor desires. High performance LC is a popular approach to analyzing beverages for caffeine, saccharin, benzoate, and other additives. Reverse-phase methods (1-5) like the one described in this experiment have been used to determine caffeine levels in coffee (2,3,5) tea (4), and soft drinks (1,5,6), with most methods including the simultaneous separation and analysis of saccharin and sodium benzoate, with minimal sample preparation required (6). With the... 

An indirect addition converts alkynes to an organozinc compound using a palladium catalyst, which then reacts with allylic halides. " Similarly, the reaction of an alkyne with Ti(0/Pr)4/2 /PrMgCl followed by addition of an alkyne leads to a conjugated diene. 

Protection Agency has promulgated a rule prohibiting the use of nitrites in diethanolamine-containing metal removal fluids for this same reason. Mono-and triethanolamines are listed as potential indirect additives in foods. 

Hydride nucleophiles can give substitution directly, via reversible addition or by an indirect (addition-protonation) mechanism. In the tetrahydronaphtha-lene complex (31), replacement of a methoxy group by hydride gave (32), using LiAlH4 followed by oxidative demetallation [53]. 

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