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 (3060× g, 10 min, 22 °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.