Optimization of a micro-scale extension test for rehydrated vital wheat gluten

Micro-scale extension tests are useful to assess the viscoelastic properties of rehydrated vital wheat gluten, but currently there is no standardized procedure. Therefore, a default experimental setup was optimized by systematically varying one parameter (hydration time, type of centrifuge, centrifugation speed, centrifugation time, rest period, and test speed) at a time. After data analysis and statistical evaluation taking reproducibility, discrimination of different samples, and duration of analysis into account, the optimized parameters were a hydration time of 5 min, centrifugation (3060x g, 10 min, 22 degrees C, swinging-bucket rotor) in a custom-made Teflon mold, a rest period of 15 min and measurement at a test speed of 3.3 mm/s with the SMS/Kieffer Dough and Gluten Extensibility Rig fitted to a texture analyzer. This optimized method may be used for an international collaborative study to have its performance validated and allow its approval by international standardization organizations. (C) 2016 Elsevier Ltd. All rights reserved.