The Thermal Decomposition of Carbohydrates. Part II. The Decomposition of Starch

Radioprotective thermally generated free-radical dextrins

“…Even 2 h heating at 130℃ (annealing) is considered as fairly behavioral and small structural changes which can be noted, resulting from minor ordering of some structural defects in the granules [19,20] . Elevated temperature gradually cancels original semi-crystalline packing of the polysaccharides in granules accompanied by breaking of the glycosidic bonds dehydration and other types of decomposition manifested by evolution of small molecules such as methane, ethane, and carbon dioxide [8] . Some decay of the semicrystalline structure could be observed in powder X-ray diffractograms of cornstarch heated to 230℃ and elevating temperature by further 20℃ clearly led to amorphous product (Figure 1).…”

“…In contrast to radiolysis, thermolysis of starch at 250-300℃ [8,9] results in yellowish to dark brown dextrins called British gums (BG), which contain a considerable, depending on the time and temperature of the starch processing, concentration of stable unpaired spins [10][11][12][13][14] . They are not mutagenic [15] .…”

Resistant Dextrins as Prebiotic

“…There are four major groups of dextrins: maltodextrins produced by hydrolysis of dispersed starch by action of liquifying enzymes such as amylase, degradation products by acid hydrolysis of dispersed starch, cyclodextrins, and pyrodextrins produced by the action of heat alone or in a combination with acid on dry granular starch. On the market pyrodextrins are available in three major varieties: British gums, white dextrins and yellow dextrins [5,105,122].…”

“…In this way, white dextrins are formed. Because (16) bonds are more resistant to hydrolysis than (14) bonds, these last ones undergo transformation into (16) bonds [105].…”

“…The only thing know is that in this process deprotonating of hydroxyl groups at C-2 and C-3 is the first stage. In the presence of oxidating agents atom C-1 of terminal glucose units are being oxidized to carboxyl group [105]. Summing up, as a result of hydrolysis the reductive ends of the starch become glucose cations, which undergo intramolecular dehydration forming (16)-anhydro--D-glucopyranose unit or they take part in formation of intermolecular bonds (transglycolization).…”