EVALUATING VITAL WHEAT GLUTEN QUALITY

A simple compression test was developed to evaluate the relative stren gth oi vital wheat gluten. The developed method was reproducible, diff erentiated the glutens by their relative strengths, and correlated hig hly with the gluttens' breadbaking qualities. The compression distance s (relative strengths) of glutens that were lyophilized were intersper sed among those of glutens that were dried commercially. Mild heal tre atment (70 degrees C) decreased gluten solubility but did not alter gl uten strength. More extreme heating (30 min at 80 degrees C or 15 min at 90 degrees C) increased gluten strength. Heating at 70 degrees C wa s sufficient to gelatinize the contaminant starch in the gluten but wa s not severe enough to alter the relative strength of the gluten. Four commercial glutens tested showed starch endotherms, indicating that t hey had not been heated above 70 degrees C. Therefore, the variability among commercial wheat glutens is apparently not caused by heat damag e during drying.