Quantitative and qualitative study of arabinogalactan-peptide during breadmaking

The quantitative and qualitative changes of water-extractable arabinogalact an-peptide (WE-AGP) during a straight dough wheat bread-making process in t he flour from two wheat varieties Skirlou and Soissons were investigated. T he extractability of WE-AGP remains constant or increases slightly as a res ult of the bread-making process (increases of 12% for Skirlou and 10% for S oissons). This contrasts with the great increase in extractability of the w ater-extractable arabinoxylan (WE-AX) (29% for Skirlou and 77% for Soissons of the initially present WE-AX). No changes in arabinose substitution of W E-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 proce ss. 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. T he 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 abov e 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, 1334-1 343), there is no specific interaction between WE-AGP and gluten proteins i n a straight dough bread-making process.