Effects of a cross-linking enzyme on the protein composition, mechanical properties, and microstructure of Chinese-style noodles

Flours, representing the three major classes of Canadian wheat used for the production of noodles, were processed into fresh, Chinese-style, yellow alkaline noodles (YAN) with and without (1 w/w, fwb) the cross-linking enzyme transglutaminase (TG). The flours, YAN-TG and YAN + TG were sequentially extracted to remove albumins and globulins, followed by a series of 50% propanol extractions (±4% DTT) and 50% propanol +4% DTT +1% acetic acid to ensure removal of all extractable gliadin and glutenin components. Reverse-phase (RP) HPLC analyses of all propanol extracts were performed and the change in protein composition and distribution reported. Raw YAN, ±TG, were simultaneously evaluated for their fundamental rheological characteristics using ultrasound and stress relaxation testing. Significant changes in the distribution of protein within the various propanol extracts were observed when the flours were processed into YAN ± TG. The amount of unextractable protein increased by as much as ∼3-fold in YAN + TG, and ∼2-fold in YAN-TG, relative to that present in their respective source flour. Significant differences were observed within and between the YAN variety samples for the longitudinal modulus and the tan delta, when processed ±TG. Significant correlations (p = 0.05) were observed between protein composition, ultrasonic and stress relaxation parameters.