Thermal degradation of different crystalline forms of lactose

Solubility and physical properties of sugars in pressurized water

“…There is an increase in lactulose formation as temperature and pressure (from (15 to 120) bar) increases. But, the maximum values obtained are less than 2.3 mg lactulose/g solution, which represents only 0.4% of the 0.981 g lactose/g water at 423 K. The literature also shows that at 423 K, enolization of lactose occurs, resulting in 26% of degradation [34] but a pressure of 4000 bar prevents lactose isomerization at basic pH of 10 and 60°C [35]. Therefore, the use of PW in a dynamic flow high pressure system avoids degradation of lactose.…”

Monosaccharide anhydrides, new markers of toasted oak wood used for ageing wines and distillates

“…The formation of these new compounds can be explained by the thermal degradation of cellulose and hemicelluloses, which is produced during the toasting step. This degradation implies the releasing of their monomers: glucose, mannose and galactose which, under anhydrous conditions, suffer an intramolecular dehydratation by loss of molecules of water originating from MAs (Paez, Martínez-Castro, & Olano, 1987). The presence of MAs in oak wood used in barrelmaking for wine and spirit ageing has not previously been reported.…”

A Raman spectroscopic study of the pyrolysis of lactose and tannins

“…The preferred crystal structure of lactose contains α-lactose monohydrate; the other stable polymorphs of lactose are anhydrous α-lactose and anhydrous β-lactose. [24][25][26][27][28][29][30] As α-lactose monohydrate is needed as a starting point for obtaining any of the other polymorphs and is so far the only polymorph commercially available in its pure form, it is the most prominent subject of research among the crystalline forms of lactose. 27 Another solid form of lactose is amorphous lactose, which features both αand β-lactose molecules.…”

“…24 α-lactose monohydrate decomposes at its melting point of 201 C-202 C, 24 and its most prominent pyrolysis products are various isomers of galactose and glucose, owing to the glycosidic bond being broken during heat treatment. 29 Lactose samples were provided as a powder in the form of α-lactose monohydrate (DAB 9, DM-Markt, Germany).…”

“…The proposed first pyrolysis reactions usually include the hydrolysis of the glycosidic bond between the monosaccharide rings and the elimination of water, which result in the formation of glucose, galactose, and anhydro sugars like levoglucosan or levogalactosan. 29 In this work, only the remaining solid parts of the pyrolyzate were investigated. The samples changed their color from white (untreated lactose powder) to eggshell (annealed to 180 C) to caramel (210 C) to black (227 C and above).…”