Determination of the molecular weight distribution of non-enzymatic browning products formed by roasting of glucose and glycine and studies on their effects on NADPH-cytochrome c-reductase and glutathione-S-transferase in Caco-2 cells

Citation
T. Hofmann et al., Determination of the molecular weight distribution of non-enzymatic browning products formed by roasting of glucose and glycine and studies on their effects on NADPH-cytochrome c-reductase and glutathione-S-transferase in Caco-2 cells, NAHRUNG, 45(3), 2001, pp. 189-194
Citations number
50
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Food Science/Nutrition
Journal title
NAHRUNG-FOOD
ISSN journal
0027-769X → ACNP
Volume
45
Issue
3
Year of publication
2001
Pages
189 - 194
Database
ISI
SICI code
0027-769X(200106)45:3<189:DOTMWD>2.0.ZU;2-Y
Abstract
After thermal treatment of a mixture of glucose and glycine for 2 h at 125 degreesC, about 60% of the starting material was converted into nonsoluble, black pigments, whereas 40% of the mixture was still water-soluble. Dialys is of the latter fraction revealed 30.4% of low molecular weight compounds (LMWs; MW < 10 000 De) and 10.0% high-molecular weight products [HMWs; MW g reater than or equal to 10000 Dal. The water-soluble Maillard reaction prod ucts (MRPs) were separated by gel permeation chromatography and ultrafiltra tion, revealing that 60% of the water-soluble products of the total carbohy drate/amino acid mixture had MWs < 1 000 Da and consisted mainly of non-col oured reaction products. MRPs with MWs between 1000 and 30000 Da were Found in comparatively low yields (about 1.3%). In contrast, about 31.1% of the MRPs exhibited MWs > 30000 Da, amongst which 14.5% showed MWs > 100000 Da, thus indicating an oligomerisation of LMWs to melanoidins under roasting co nditions. To investigate the physiological effects of these MRPs, xenobioti c enzyme activities were analysed in intestinal Caco-2 cells. For Phase-I N ADPH-cytochrome c-reductase, the activity in the presence of the LMW and HM W fraction was decreased by 13% and 22%: respectively. Phase-II glutathione -S-transferase activity decreased by 15% and 18%, respectively, after incub ation with the LMW and the HMW fractions. Considering the different yields, 30% and 10%, respectively, of the LMW and the HMW fractions, the total amo unt of the LMW fraction present in the glucose-glycine mixture is more acti ve in modulating three enzyme activities than that of the HMW fraction.