Relation to Sucrose

Aberg (1949) noted that the fall of ascorbic acid may be arrested in darkened detached leaves if these are floated in sucrose solutions, but he later showed (Aberg, 1953) that similar results could be obtained with other sugars. There is therefore no evidence from this work that sucrose per se had any specific effect on the synthesis of ascorbic acid. Evidence is, however, available which suggests that conditions which promote the synthesis of sucrose appear to favor the synthesis of ascorbic acid. We have already seen that oxygen is necessary for the synthesis of ascorbic acid, and it has been shown to be equally necessary for the synthesis of sucrose (Nelson and Auchincloss, 1933 McCready and Hassid, 1941).  

This relationship is sometimes obscured by the interaction of other factors (Barker and Mapson, 1952), and such evidence implies that the connection between these two substances is not direct. A connection between the level of sucrose and ascorbic acid has also been emphasized in experiments in which detached leaves have been treated with several enzymic poisons (Mapson and Barker, 1948). Ascorbic acid disappears from detached leaves when these are supplied with solutions of iodoacetate, fluoride, or arsenite. In each case the disappearance of ascorbic acid was preceded by a parallel fall of sucrose. It is clearly too soon to speculate 

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In addition to variations in a biofilm s polymer content related to sucrose consumption, bacteria that metabolize salivary urea or dietary arginine also affect biofilm pH. The enzyme urease converts salivary urea to ammonia and carbon dioxide (Sect. 12.1.2),... 

Certainly, the most accurate determination of sucrose loss across any unit process in sugar manufacture would consist of analysis for a marker compound that is an end product of sucrose hydrolysis and monosaccharide degradation, and that could be directly related to sucrose loss. Unfortunately, no likely marker compound has been identified. Preliminary GC-MS analysis of MJ and 3rdS samples from this study indicate that most identifiable compounds (e.g., kestoses) are present in both MJ and 3rdS. 

Starch synthesis is closely related to sucrose synthesis (see Chapters IX and XII). Experiments with isotopically labeled sugars have shown that leaves can form starch from externally supplied glucose, fructose, and sucrose, as well as from several other compounds. Starch is also formed from carbon dioxide during photosynthesis. It was found (78) that when labeled carbon dioxide was fed to leaves, the starch became labeled before the free sugars. Labeled glucose and glucose 1-phosphate did not contribute an... 

The literature in this field is confusing because of a somewhat haphazard method of nomenclature that has arisen historically. This is compounded by some mistakes in structure determination, reported in early papers, and which are occasionally quoted. The first part of this chapter deals with nomenclature and with a brief overview of early work. Subsequent sections deal with the formation and metabolism of di-D-fructose dianhydrides by micro-organisms, and the formation of dihexulose dianhydrides by protonic and thermal activation. In relation to the latter topic, recent conclusions regarding the nature of sucrose caramels are covered. Other sections deal with the effects of di-D-fructose dianhydrides upon the industrial production of sucrose and fructose, and the possible ways in which these compounds might be exploited. An overview of the topic of conformational energies and implications for product distributions is also presented. 

Structurally related to saccharin are the oxathiazinone dioxides (104). Clauss and coworkers synthesized a series of these compounds, and demonstrated that they possess intense sweetness. Acesulfame-K, the potassium salt of 3,4-dihydro-6-methyl-l,2,3-oxathiazin-4-one 2,2-dioxide (104) has a sweetness intensity 130 times that of sucrose. 

Mutans streptococci are the major pathogenic organisms of dental caries in humans. The pathogenicity is closely related to production of extracellular, water-insoluble glucans from sucrose by glucosyltransferase and acid release from various fermentable sugars. Poly(catechin) obtained by HRP catalyst in a phosphate buffer (pH 6) markedly inhibited glucosyltransferase from Streptococcus sorbrinus 6715, whereas the inhibitory effect of catechin for this enzyme was very low. 

A wider problem exists with the possible role of liquid medications in dental caries formation [63], The extent of acid production in the oral cavity is closely related to caries formation. In a study of liquid medication, investigators have observed that medications with sucrose concentrations higher than 15% were able to significantly lower pH there was an inverse relation between sucrose content and a decrease in oral cavity pH [64], In a comparison of sorbitol and sucrose-sweetened liquid iron preparations, only sucrose-containing products produced a significant decrease in oral cavity pH [65],... 

Cavitation bubbles work as nucleation sites of particles. For example, in a supercooled sucrose solution, nucleation of ice crystals induced by cavitation bubbles has been experimentally observed [72], This phenomenon has been called sonocrys-tallization [73]. Although there are some papers on the mechanism of sonocrystal-lization, it has not yet been fully understood [74, 75]. It has been reported that the distribution of crystal size in sonocrystallization is narrower than that without ultrasound [73]. It may be related to the narrower size distribution of sonochemi-cally synthesized particles compared to that without ultrasound [76, 77]. Further studies are required for the mechanism of particle nucleation by ultrasound. 

Early reports on levan are obscured by incomplete descriptions of impure products.2 96 Greig-Smith found that Bacillus levaniformans(1) produced levan from sucrose96" in suitable nutrient solutions, but not from D-glucose, D-fructose, lactose or maltose.966 He therefore assumed that levan could only be formed from the nascent D-fructose and D-glucose resulting from the inversion of sucrose. Hydrolysis of levan yielded D-fructose only, and analysis of levan agreed with the empirical formula (C HiriOi) it was noted that levan was closely related to inulin but was not identical with it. 

Sweetness free, or at least virtually free, from calories establishes the need for intense sweeteners while suitability for diabetics, absence of carcinogenicity with functionality similar to sucrose and related carbohydrates form the basis for application of bulk sweeteners. 

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