Saccharides caramel

The treatment of sucrose with anhydrous HF89 results in the formation of a complex mixture of pseudooligo- and poly-saccharides up to dp 14, which were detected by fast-atom-bombardment mass spectrometry (FABMS). Some of the smaller products were isolated and identified by comparison with the known compounds prepared86 88 a-D-Fru/-1,2 2,1 -p-D-Fru/j (1), either free or variously glucosylated, was a major product, and this is in accord with the known stability of the compound. The mechanism of formation of the products in the case of sucrose involves preliminary condensation of two fructose residues. The resultant dianhydride is then glucosylated by glucopyranosyl cation.89 The characterization of this type of compound was an important step because it has permitted an increased understanding of the chemical nature of caramels. 

Caramel colors are brown pigments produced by reaction of a saccharide with a browning accelerator. They can be considered a natural material as caramels may be formed in food. Caramels are prepared as food colors by heating a solution of a sugar (commonly glucose or sucrose) with the accelerator. The caramels can be classified as one of four types [1] shown in Table 11.1.1. 

Anhydrosugars can be utilized for the synthesis of some derivatives, such as amino sugars and others. Dehydration is the first step of sugar caramelization. Further heating of dehydrated saccharides results in the formation of three subsequent compounds called caramelan, caramelen, and caramelin (Tomasik et al., 1989) ... 

In strongly acidic media, saccharides produce furan derivatives in a sequence of reactions that are rearrangements and dehydrations followed by cyclization. Similar products are available thermally. Pentoses and hexoses give furan-2-aldehyde and 5-hydroxymethylfuran-2-aldehyde, respectively. Both of these products are responsible for the specific aroma of caramel and burnt sugar. 

There is a concern about harm coming from the free radical character of caramels. However, they were proven (Barabasz et al., 1990) to be nonmutagenic. Thermal processing of saccharides and polysaccharides containing foodstuffs... 

Caramel is the amorphous dark brown coloring material formed by heating saccharides in the presence of selected accelerators. It consists of a mixture of volatile and nonvolatile low-molecular-weight compounds and high molecular compounds. The composition and coloring power of caramel depend on the type of raw material and... 

However, the thermal decomposition of carbohydrates between 250 and 1000 has also been studied, and this aspect is of theoretical and practical interest. In this Chapter, the decomposition of saccharides by heat is discussed in two Sections, devoted respectively to caramelization of saccharides and their pyrolysis above 250°. 

In 1858, in his fundamental work, Gelis described some components (caramelan, caramelen, and caramelin) of caramel from saccharides, and the... 

Other mono- and di-saccharides have also been considered as sources of caramel. "It has been found that molasses may be used, as it already contains compounds analogous to caramel. Although molasses may... 

The observations from the reactions of amino acids with mono- and di-saccharides have been logically employed for caramelization of molasses. A strong color, stable to tannin, sodium chloride, and alcohol was obtained at pH 9 with glycine or L-lysine as the catalyst. ... 

Lactose (98% of purity) was supplied from Fluka, octa-O-acetyl-lactose was synthesized for the purpose of this paper[ ]. The chemical structures of both investigated saccharides are presented in Fig 1. In order to avoid caramellization of lactose (this disaccharide caramelizes relatively easy) the sample was heated very quickly to its melting point and when whole sample was molten it was supercooled very quickly. Isobaric dielectric measurements at ambient pressure were carried out using a Novo-Control GMBH Alpha dielectric spectrometer (10 -10 Hz). The samples were placed between two stainless steel flat electrodes of the capacitor with gap 0.1 mm. The temperature was controlled by the Novo-Control Quattro system, with use a nitrogen-gas cryostat. Temperature stability of the samples was better than 0.1 K... 

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