American Chemical Society, Books and Journals Division
Journal of Agricultural and Food Chemistry vol:46 issue:12 pages:5026-5030
The quantitative and qualitative changes of water-extractable arabinogalactan-peptide (WE-AGP) during a straight dough wheat bread-making process in the flour from two wheat varieties Skirlou and Soissons were investigated. The extractability of WE-AGP remains constant or increases slightly as a result of the bread-making process (increases of 12% for Skirlou and 10% for Soissons). This contrasts with the great increase in extractability of the water-extractable arabinoxylan (WE-AX) (29% for Skirlou and 77% for Soissons of the initially present WE-AX). No changes in arabinose substitution of WE-AX (0.47-0.50 for Skirlou, 0.52-0.54 for Soissons) and WE-AGP (0.66-0.70 for Skirlou, 0.69-0.72 for Soissons) occurred during the bread-making process. In contrast to differences found in molecular weight distribution of WE-AX, no differences in molecular weight distribution of WE-AGP as a result of processing were observed. Apparent molecular weights of 2.4 x 10(4) and 2.2 x 10(4) were found for WE-AGP samples of flour and doughs at different stages of the breadmaking process for Skirlou and Soissons, respectively. The H-1 NMR spectra (300 MHz, D2O, 85 degrees C) of the WE-AGP isolated from flour, dough, and bread fraction were comparable. Taken together, the above data suggest that, unlike what can be observed in gluten agglomeration in dilute systems (Roels, S. P., et al. J. Agric. Food Chem. 1998, 46, 1334-1343), there is no specific interaction between WE-AGP and gluten proteins in a straight dough bread-making process.