Soy Protein Concentrate (SPC) (Alpha 8® IP, 70% protein, 18% dietary fibre, 7% ash, 2% fat; 19.6% total carbohydrates) was purchased from Solae (St. Louis, Missouri, USA). SPC samples were produced using a co-rotating twin-screw extruder (XTS 19, Xtrutech, UK). The screws had a diameter of 19 mm and a Length/Diameter ratio of 25. In the transition zone, a breaker plate was mounted, and using a die adapter, a cooling die was attached. This barrel had an internal geometry of 19 x 7 x 300 mm (W x H x L). The protein powder was fed into the extruder using a volumetric feeder (Brabender Technologie, Utrecht, The Netherlands). Water was fed into the water inlet using a constant-flow pump (Master Flex Easy Load II, Gelsenkirchen, Germany). The pH of the extrudate was adjusted with citric acid (0.35 M for pH 4.2 and 0.025 M for pH 6.5) via the water feed. The final pH of the extrudates sample was measured using a solid-state pH Meter (MetrOhm 949 pH Meter with Spearhead Probe inc. Pt1000 temperature sensor, Herisau, Switzerland). The extruder was segmented into four separate temperature zones, set at 80°C, 120°C, 160°C, and 135°C respectively. The temperature of the cooling water for the cooling die was set at 65°C. The screw speed was set at 350 rpm, and the moisture content was 54% at a throughput of 5 kg/h. A schematic overview can be seen in Fig. .1. To perform a deadstop, first, the extruder was fed with plain tap water and made to run steady-state for at least 15 minutes after which the barrel and cooling die were rapidly cooled and the extruder was switched off. Water pressure was used to expel the ribbon from the cooling die. Extrudate and deadstop SPC ribbon samples were immediately bagged and submerged in ice water. Then samples were stored at -18°C in the freezer.