In fruits

D-fructose, C HijOo. Crystallizes in large needles m.p. 102-104 C. The most eommon ketose sugar. Combined with glucose it occurs as sucrose and rafftnose mixed with glucose it is present in fruit juices, honey and other products inulin and levan are built of fructose residues only. In natural products it is always in the furanose form, but it crystallizes in the pyranose form. It is very soluble in... 

Pectin also contains araban and galactan. Il is present in fruits, root vegetables and other plant products, and confers on jams their typical gelling property. Pectin is manufactured as a white powder, soluble in water, and used to assist the setting of jams and jellies, and for numerous other purposes. Low melhoxyl pectins, with under 7% methoxyl, give firmer gels than pectins proper. 

Polysaccharides are macromolecules which make up a large part of the bulk of the vegetable kingdom. Cellulose and starch are, respectively, the first and second most abundant organic compounds in plants. The former is present in leaves and grasses the latter in fruits, stems, and roots. Because of their abundance in nature and because of contemporary interest in renewable resources, there is a great deal of interest in these compounds. Both cellulose and starch are hydrolyzed by acids to D-glucose, the repeat unit in both polymer chains. 

Sample pre-treatment. Novel procedures of electrochemical sample treatment have been proposed to decrease the signal interference with native cholinesterase inhibitors present in fruits and vegetables. Polyphenolic compounds were removed by electrolysis with soluble A1 anode followed by the oxidation of thionic pesticides with electrogenerated chlorine. The procedure proposed makes it possible to decrease the background current and the matrix effect by 80-90%. Thus, the detection limits of about 5 ppb of Pai athion-Methyl and Chloropyrifos-Methyl were obtained in spiked grape juice without any additional sepai ation or pre-concentration stages. 

While there is limited evidence to suggest that consumption of diets high in fruit and vegetables is associated with a reduction in risk of breast cancer, the... 

The study of biochemical natural products has also been aided through the application of two-dimensional GC. In many studies, it has been observed that volatile organic compounds from plants (for example, in fruits) show species-specific distributions in chiral abundances. Observations have shown that related species produce similar compounds, but at differing ratios, and the study of such distributions yields information on speciation and plant genetics. In particular, the determination of hydroxyl fatty acid adducts produced from bacterial processes has been a successful application. In the reported applications, enantiomeric determination of polyhydroxyl alkanoic acids extracted from intracellular regions has been enabled (45). 

M. De Paoli, M. Barbina Taccheo, R. Mondini, A. Pezzoni and A. Valentino, Determination of organophosphoms pesticides in fruits by on-line size-exclusion chi O-matography-flame photometric detection , 7. Chromatogr. 626 145-151 (1992). 

Stein-kem, m. stone (in fruit, in burnt lime), -kitt, m. cement for stone, -klee, m. melilot (Melilotua, esp. M. officinalia) white clover (Trifolium repena). -kohle, /. mineral coal, coal. 

An alkene, sometimes caJled an olefin, is a hydrocarbon that contains a carbon-carbon double bond. Alkenes occur abundantly in nature. Ethylene, for instance, is a plant hormone that induces ripening in fruit, and o-pinene is the major component of turpentine. Life itself would be impossible without such alkenes as /3-carotene, a compound that contains 11 double bonds. An orange pigment responsible for the color of carrots, /3-carotene is a valuable dietary source of vitamin A and is thought to offer some protection against certain types of cancer. 

Fructose is a sugar commonly found in fruit. A sample of fructose,... 

The alcohol in most liqueurs is ethanol, C2H5OH. It is produced by foe fermentation of the glucose in fruit or grain. 

Acids, for example those in fruit juices, catalyze rust formation because they furnish H+(aq) to accept electrons from the iron, causing it to dissolve faster. Oxygen gas is necessary to oxidize Fe+S to Fe2Oa. The presence of water facilitates the migration of Fe+2 from the reaction site. The resulting reduction in Fe+2 concentration allows more to be formed. Support for these ideas comes from the frequent observation that when... 

To illustrate how some filth elements may be detected, measured, and evaluated in fruit and vegetable products, let us consider tomatoes, which are subject to at least three types of depredation worms, flies, and mold. 

Pectinase, protease Aspergillus niger, A. aureus Clarifying agents in fruit juice... 

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