Solubilisation and characterisation of wheat gluten proteins: correlations between the amount of aggregated proteins and baking quality.

Abstract

AbstractA comparison was made of the effectiveness of various solvents in extracting protein from wheat gluten. The best proved to be 0.055m cetyltrimethyl ammonium bromide‐6m urea‐0.01m acetic acid. When extracts were separated on columns of controlledpore glass, with a nominal exclusion limit of 1.2 × 106 daltons for molecules in the extended form, two peaks were obtained termed F1 and F2. F1 was excluded from the column and contained material which was stable in the absence of reducing agent but was markedly reduced in size in the presence of 2‐mercaptoethanol. SDS‐PAGE showed that F1 was enriched in high molecular weight polypeptides (about 100 000 daltons) and also contained polypeptides with molecular weights in the range 30 000–45 000. F2 consisted almost entirely of polypeptides with molecular weights of less than 50 000. The ratio of F1 :F2 in different varieties varied from 0.1 to 0.58 and this variation was correlated with the NIAB potential breadmaking quality score. However, there did not appear to be any difference between the total amounts of high molecular weight polypeptides in a poor and a good breadmaking variety.